This review is devoted to current and emerging techniques in gastrointestinal (GI) imaging. It is divided into three sections focusing on areas that are both interesting and challenging: imaging of the small bowel and appendix, imaging of the colon and rectum and finally liver and pancreas in the upper abdomen.
Gastrointestinal Imaging A Core Review Editors Wendy C Hsu, MD Co-Director, Diagnostic Radiology Residency Teaching Coordinator, Gastrointestinal Imaging Department of Radiology Virginia Mason Medical Center Seattle, Washington Felicia P Cummings, MD Section Chief, General Radiology Department of Radiology Virginia Mason Medical Center Seattle, Washington Acquisitions Editor: Ryan Shaw Product Development Editor: Lauren Pecarich Marketing Manager: Dan Dressler Production Project Manager: David Orzechowski Senior Manufacturing Coordinator: Beth Welsh Design Coordinator: Elaine Kasmer Prepress Vendor: SPi Global Copyright © 2016 by Wolters Kluwer All rights reserved This book is protected by copyright No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews Materials appearing in this book prepared by individuals as part of their official duties as U.S government employees are not covered by the above-mentioned copyright To request permission, please contact Wolters Kluwer at Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103, via email at permissions@lww.com, or via our website at lww.com (products and services) 987654321 Printed in China Library of Congress Cataloging-in-Publication Data Names: Hsu, Wendy C., editor.|Cummings, Felicia P., editor Title: Gastrointestinal imaging : a core review/editors, Wendy C Hsu, Felicia P Cummings Other titles: Gastrointestinal imaging (Hsu)|Core review series Description: Philadelphia : Wolters Kluwer, [2016]|Series: Core review series|Includes bibliographical references and index Identifiers: LCCN 2015039608|ISBN 9781496307187 (alk paper) Subjects:|MESH: Digestive System—radiography—Examination Questions.|Digestive System Diseases— diagnosis—Examination Questions.|Diagnostic Imaging—methods—Examination Questions.|Diagnostic Techniques, Digestive System—Examination Questions Classification: LCC RC804.R6|NLM WI 18.2|DDC 616.3/07572—dc23 LC record available at http://lccn.loc.gov/2015039608 This work is provided “as is,” and the publisher disclaims any and all warranties, express or implied, including any warranties as to accuracy, comprehensiveness, or currency of the content of this work This work is no substitute for individual patient assessment based upon healthcare professionals’ examination of each patient and consideration of, among other things, age, weight, gender, current or prior medical conditions, medication history, laboratory data and other factors unique to the patient The publisher does not provide medical advice or guidance and this work is merely a reference tool Healthcare professionals, and not the publisher, are solely responsible for the use of this work including all medical judgments and for any resulting diagnosis and treatments Given continuous, rapid advances in medical science and health information, independent professional verification of medical diagnoses, indications, appropriate pharmaceutical selections and dosages, and treatment options should be made and healthcare professionals should consult a variety of sources When prescribing medication, healthcare professionals are advised to consult the product information sheet (the manufacturer’s package insert) accompanying each drug to verify, among other things, conditions of use, warnings and side effects and identify any changes in dosage schedule or contraindications, particularly if the medication to be administered is new, infrequently used or has a narrow therapeutic range To the maximum extent permitted under applicable law, no responsibility is assumed by the publisher for any injury and/or damage to persons or property, as a matter of products liability, negligence law or otherwise, or from any reference to or use by any person of this work LWW.com To my husband Alex and my little goofballs Ryan and Derek —WENDY C HSU To David, Nathan, and Cameron who make me happy every day —FELICIA P CUMMINGS Contributors Michael A Cecil, MS, RT (R) (MR) Director of Advanced Imaging Department of Radiology Virginia Mason Medical Center Seattle, Washington Kevin J Chang, MD, FSAR Associate Professor of Diagnostic Imaging The Warren Alpert Medical School of Brown University Director, CT Colonography Department of Diagnostic Imaging Rhode Island Hospital, The Miriam Hospital, Women & Infants Hospital, Rhode Island Medical Imaging Providence, Rhode Island Anil Chauhan, MD Assistant Professor of Radiology University of Pennsylvania School of Medicine Division of Abdominal Imaging Department of Radiology Hospital of the University of Pennsylvania Philadelphia, Pennsylvania Ahmad F Haidary, MD Clinical Assistant Professor Wayne State University Senior Staff Radiologist Abdominal and Cardiovascular Imaging Henry Ford Health System Detroit, Michigan Peter S Liu, MD Staff Radiologist, Abdominal Imaging Imaging Institute Cleveland Clinic Cleveland, Ohio Michael F McNeeley, MD Assistant Professor of Radiology, Body Imaging University of Washington School of Medicine Associate Program Director, Body Imaging Fellowship Associate Program Director, Radiology Residency Co-Director, Image-Guided Body Procedures University of Washington Medical Center Seattle, Washington Mishal Mendiratta-Lala, MD Clinical Assistant Professor University of Michigan School of Medicine Abdominal and Cross-Sectional Interventional Radiology University of Michigan Medical Center Ann Arbor, Michigan Matthew A Morgan, MD Assistant Professor of Clinical Radiology University of Pennsylvania School of Medicine Division of Abdominal Imaging Department of Radiology Hospital of the University of Pennsylvania Philadelphia, Pennsylvania Shuchi K Rodgers, MD Clinical Assistant Professor of Radiology Sidney Kimmel Medical College at Thomas Jefferson University Director of Ultrasound and Body MRI Department of Radiology Einstein Medical Center Philadelphia, Pennsylvania Claire K Sandstrom, MD Assistant Professor University of Washington School of Medicine Emergency and Trauma Radiology Harborview Medical Center Seattle, Washington Drew A Torigian, MD, MA, FSAR Associate Professor of Radiology University of Pennsylvania School of Medicine Clinical Director, Medical Image Processing Group (MIPG) Department of Radiology Hospital of the University of Pennsylvania Philadelphia, Pennsylvania Series Foreword This volume in the Core Review Series, Gastrointestinal Imaging: A Core Review by Dr Wendy Hsu and Dr Felicia Cummings covers the vast field of gastrointestinal imaging in a manner that I am confident will serve as a useful guide for residents to assess their knowledge and review of the material in a question-style format that is similar to the ABR Core examination Dr Wendy Hsu and Dr Felicia Cummings have succeeded in producing a book that exemplifies the philosophy and goals of the Core Review Series They have done a meticulous job in covering many key topics, providing quality images, and detailed answer explanations The multiple-choice questions have been divided logically into chapters so as to make it easy for learners to work on particular topics as needed Each question has a corresponding answer with a thorough explanation of not only why a particular answer option is correct but also why the other answer options are incorrect There are also suggested readings provided for each question for those who want to delve more deeply into a specific subject This format is also useful for radiologists preparing for Maintenance of Certification (MOC) The intent of the Core Review Series is to provide the resident, fellow, or practicing physician a review of the important conceptual, factual, and practical aspects of a subject by providing approximately 300 multiple-choice questions, in a format similar to the ABR Core examination The Core Review Series is not intended to be exhaustive but to provide material likely to be tested on the ABR Core exam and that would be required in clinical practice As Series Editor of the Core Review Series, I have had the great pleasure to work with many outstanding individuals across the country who contributed to the series This series represents countless hours of work and involvement by so many that it could not have come together without their participation It has been very gratifying to see the growing popularity and positive feedback the authors of the Core Review Series have received from many reviews I would like to congratulate Dr Wendy Hsu, Dr Felicia Cummings, and their contributors for a superb job in covering the daunting topic of gastrointestinal radiology in a way that is both concise and easy to follow I believe Gastrointestinal Imaging: A Core Review will serve as an excellent resource for residents during their board preparation and a valuable reference for fellows and practicing radiologists Biren A Shah, MD, FACR Series Editor Preface With the new Core Examination in radiology, the American Board of Radiology is given a chance to take a critical look at resident education and reshape the nature of board preparation Understanding that image interpretation lies at the heart of radiology, the new examination is designed to be “image rich” with approximately 80% of the questions associated with images As with the former written examination, the new exam will continue to test the knowledge base of the resident, with about 40% of the questions testing factual information The remaining 60% of the questions are directed toward higher level analysis including clinical management, such as was emphasized during the former oral boards examination In this text, we present over 300 core review questions organized according to the sections established in the ABR study guide These feature images from the best cases in our teaching files across multiple modalities Included are both multiple choice and extended matching questions Physics questions emphasize common issues encountered in real practice The answers aim to address key teaching points and to expand the discussion with related examples when relevant Explanations are provided for incorrect answers that may still seem plausible after the correct answer is given The variety of organs, diversity of diseases and treatments, and spectrum of imaging modalities involved in gastrointestinal radiology are both daunting and fascinating Every day on a busy body imaging service brings forth a number of “great” cases: an unusual finding, a satisfyingly classical presentation, and an answer to a clinical mystery This subspecialty is anything but boring or routine We are fortunate at our institution to have an impressive group of clinical colleagues who supply us with a bounty of interesting cases Their expertise and appreciation form the basis for a most rewarding collaboration We are thankful to our contributors who assisted us with the challenging task of capturing the pathologic spectrum of diseases And of course, we are indebted to our residents whose questions keep us on our toes and make us better radiologists It is in recognition of their hard work and enthusiasm that we have decided to create this book They represent our educational legacy, and we wish them successful and fulfilling careers We hope that you will find this volume a rich and rewarding experience for the boards and beyond Wendy C Hsu Felicia P Cummings Acknowledgments With gratitude to Biren Shah and Lauren Pecarich for their advice and assistance Answer C.Diffuse calcifications, seen throughout the pancreas in this case, are specific for chronic pancreatitis Chronic alcohol consumption accounts for 70% to 90% of cases of chronic pancreatitis in developed countries Less common causes are chronic biliary tract disease, hereditary pancreatitis, cystic fibrosis, hyperlipidemia, hypercalcemia (most commonly hyperparathyroidism), medications, and pancreas divisum Chronic pancreatitis, thought to be an entity distinct from acute pancreatitis, is a disease of prolonged inflammation leading to fibrosis and gland dysfunction Focal or diffuse pancreatic calcifications are present in half of patients, visible on CT and occasionally on radiographs as shown on the following image from a different patient (arrows) References: Miller FH, Kepke AL, Balthazar EJ Chapter 97: Pancreatitis In: Gore RM, Levine MS (eds) Textbook of gastrointestinal radiology, 4th ed Philadelphia, PA: Elsevier/Saunders, 2015:1809–1837 Steer ML, Waxman I, Freedman S Chronic pancreatitis N Engl J Med 1995;332(22):1482–1490 Answer D.Imaging findings are consistent with pancreatic ductal adenocarcinoma (PDA) There is a mass (arrows) at the junction of the body and the tail of the pancreas obstructing the duct and causing tail atrophy Classically, it is best seen as a hypoenhancing area on the arterial phase (image on the bottom left) Enhancement progressively increases on later phases as expected with desmoplastic (fibrosing) lesions This hypoenhancement may initially resemble a cystic or necrotic component; however, venous phase shows subsequent solid enhancement, and there is no T2 hyperintensity to indicate fluid The tumor has occluded the splenic vein, which normally runs along the posterior margin of the pancreas Because the normal pancreas is intrinsically T1 hyperintense, most pancreatic pathology manifests as T1 hypointensity, as seen with this tumor The tail is also abnormally T1 hypointense due to atrophy from the ductal obstruction PDA is a highly aggressive malignancy arising from the ductal epithelium and accounts for 90% of all pancreatic malignancies Two-thirds are located in the pancreatic head, which can result in the double-duct sign of both pancreatic and biliary ductal dilation Prognosis is poor, with 75% of patients unresectable at diagnosis and a 5-year survival rate of 5% for all stages combined Serum CA19-9 level may be elevated and helpful in assessing response to treatment References: Boland GWL, Halpert RD Gastrointestinal imaging: the requisites, 4th ed Philadelphia, PA: Elsevier/Saunders, 2014:358– 363 Low G, Panu A, Millo N, Leen E Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas Radiographics 2011;31(4):993–1015 7a Answer D 7b Answer B 7c Answer D.This patient has direct CT evidence of laceration (white arrow) at the head–neck junction of the pancreas There are indirect signs including fluid tracking between the splenic vein and pancreas as well as fluid in the right anterior pararenal space When laceration is evident on CT, the next question is whether the main pancreatic duct is intact or injured, as this will determine the appropriate treatment On CT, the pancreatic duct is not well seen in relation to the laceration ERCP can help identify ductal injury and can be performed before, during, or after surgical exploration Complex surgery such as Whipple procedure is considered only when severe parenchymal and ductal disruption is found ERCP in this case reveals contrast extravasation (black arrow) from the duct at the level of the pancreatic head–neck junction consistent with pancreatic duct injury While the other answer choices in question 7b could result in contrast collections on ERCP, they are not correct Acinarization is from overpressurization during injection and is usually more diffuse and ill defined The bile ducts and vessels are not opacified on the ERCP, so the image is not diagnostic for either a bile leak or pseudoaneurysm When the main pancreatic duct is disrupted, surgery is almost always indicated Rarely is stenting alone successful External or percutaneous surgical drainage is usually adequate for side-branch ductal injury Pancreatic injury is typically caused by blunt trauma compressing the pancreas against the vertebral column, especially motor vehicle accidents in adults and bicycle handlebar accidents in children The pancreatic body is the portion of the pancreas injured in two-thirds of cases Pancreatic trauma can be difficult to detect, and the injured pancreas may appear normal on CT in 20% to 40% of patients imaged within 12 hours of trauma Serum amylase is often elevated after blunt pancreatic trauma but is nonspecific and may also be elevated in salivary gland, duodenal, and hepatic injuries It is a more reliable indicator of pancreatic injury if persistently elevated or rising but does not indicate the severity of injury Pancreatic injuries are also difficult to detect on ultrasound, and sonographic findings of post-traumatic edema overlap with those of acute pancreatitis References: Debi U, Kaur R, Prasad KK, et al Pancreatic trauma: a concise review World J Gastroenterol 2013;19:9003–9011 Dreizin D, Bordegaray M, Tirada N, et al Evaluating blunt pancreatic trauma at whole body CT: current practices and future directions Emerg Radiol 2013;20:517–527 Linsenmaier U, Wirth S, Reiser M, et al Diagnosis and classification of pancreatic and duodenal injuries in emergency radiology Radiographics 2008;28(6):1591–1602 Rekhi S, Anderson SW, Rhea JT, et al Imaging of blunt pancreatic trauma Emerg Radiol 2010;17:13–19 Answer B.The findings in this case are characteristic for groove (paraduodenal) pancreatitis There is a crescent of inflammatory fat stranding (arrow) identified in the groove between the pancreatic head and duodenum The pancreatic parenchyma appears normal, and there is also no evidence of inflammation of the body or tail No ductal dilation is identified The duodenum is thickened (arrowheads), with submucosal edema seen as low density deep to the thin layer of enhancing mucosa In some cases of groove pancreatitis, there may be cyst formation in the groove or in the thickened duodenal wall There is little to no retroperitoneal fluid, in contradistinction to interstitial edematous pancreatitis (IEP) Groove pancreatitis is an uncommon form of chronic pancreatitis This patient’s groove pancreatitis, as well as the diffuse hepatic steatosis seen on these images, were thought to be alcohol-related Definitive diagnosis may be difficult due to variable clinical, laboratory, and imaging features Serum lipase level can be normal or only slightly elevated In the segmental form, there is involvement of the pancreatic head, and features can overlap with pancreatic or ampullary neoplasms Enlargement of the pancreatic head may be seen in these cases, causing pancreaticobiliary ductal dilation Groove pancreatitis is strongly associated with heavy alcohol use but underlying pathophysiology is unclear Treatment is generally conservative There is no diverticulum in the vicinity of the duodenal wall thickening to indicate duodenal diverticulitis No ampullary mass is shown to indicate ampullary carcinoma Intraductal papillary mucinous neoplasm would be seen as a cyst within the pancreas and/or a dilated main pancreatic duct A duodenitis (not an answer choice) with or without a duodenal ulcer may be the cause of duodenal wall thickening and surrounding fat stranding, but duodenal ulcers are uncommonly postbulbar unless there is an environment of hyperacidity such in the setting of Zollinger-Ellison syndrome References: Perez-Johnston R, Sainani NI, Sahani DV Imaging of chronic pancreatitis (including groove and autoimmune pancreatitis) Radiol Clin North Am 2012;50(3):447–466 Raman SP, Salaria SN, Hruban RH, et al Groove pancreatitis: spectrum of imaging findings and radiologypathology correlation AJR Am J Roentgenol 2013;201:W29–W39 Answer B.This serous microcystic cystadenoma consists of a cluster of multiple small cysts separated by fibrous septae, consistent with the polycystic pattern There is also a calcified stellate central scar, which is occasionally seen in these lesions These are typically seen in the elderly population, in women more than men Serous microcystic cystadenomas can be morphologically classified into three patterns: The polycystic pattern as seen in this case shows >6 cysts that are each 90% of cases and calcium in >50% On CT, fat within the lesion would be very low in density at 180 degrees of vessel circumference) of the SMA or celiac artery is usually considered unresectable, while “abutment” (tumor contact ≤ 180 degrees of vessel circumference) is borderline resectable Fewer than a quarter of patients have potentially resectable disease at presentation Patients with borderline resectable disease may undergo neoadjuvant chemoradiation to attempt down-staging prior to resection Involvement of short segments of the main portal vein and SMV may also be borderline resectable if amenable to venous reconstruction, but more extensive involvement of these veins or occlusion may be unresectable Splenic artery and splenic vein involvement are resectable References: Coy DL, Heeter ZR Pancreas In: Lin E, Coy DL, Kanne JP (eds) Body CT: the essentials New York, NY: McGraw-Hill, 2015:131–147 Tamm EP, Balachandran A, Bhosale PR, et al Imaging of pancreatic adenocarcinoma: update on staging/resectability Radiol Clin North Am 2012;50(3):407–428 17 Answer A.Annular pancreas is an uncommon congenital anomaly The annular pancreas shown is radiologically complete, with visualization of circumferential pancreatic tissue (arrows) surrounding the duodenum If a portion of parenchyma is thinned and not visible on CT, the annular pancreas is radiologically incomplete and may be more difficult to diagnose However, ERCP and MRCP could confirm an encircling duct The normal duodenum surrounded by pancreatic tissue may be mistaken for a pancreatic head neoplasm, but tracing the course of the duodenum should reveal duodenal continuity In childhood, annular pancreas most frequently presents with duodenal obstruction In adults, annular pancreas can be found incidentally, but if symptomatic, adults most commonly present with pancreatitis In normal development, the ventral anlage passes from right to left behind the descending duodenum to fuse with the dorsal anlage, forming the uncinate process and inferior pancreatic head Abnormal migration can result in annular pancreas Treatment of symptomatic patients is surgical References: Borghei P, Sokhandon F, Shirkhoda A, et al Anomalies, anatomic variants, and sources of diagnostic pitfalls in pancreatic imaging Radiology 2013;266(1):28–36 Sandrasegaran K, Patel A, Fogel EL, et al Annular pancreas in adults AJR Am J Roentgenol 2009;193(2):455– 460 18 Answer B.MRCP with T2W coronal MIP and axial thin-section images shows a dark, well-defined filling defect (white arrow) within the main duct in the pancreatic body There is upstream dilation of the main duct and side branches with abrupt transition at the level of filling defect Findings are consistent with an obstructing ductal stone in the setting of chronic pancreatitis (CP) The stone is visible as a calcification on the fluoroscopic scout image obtained at the time of ERCP (black arrow) The most common finding in CP is dilation of the main duct and/or side branches, which is seen in two-thirds of patients Ductal dilation is caused by strictures and stone formation in CP Although parenchymal calcifications are difficult to detect on MRI, intraductal stones are well demonstrated as dark foci due to the brightness of the surrounding ductal fluid on T2W images Other features of CP include gland atrophy, pseudocysts, pseudoaneurysm, and splenic vein thrombosis CP in the head may cause biliary as well as pancreatic ductal dilation, resulting in the double-duct sign Amylase-rich ascites or pleural fluid may be the sequela of pseudocyst rupture or fistulization Treatment of obstructing ductal strictures and stones may improve chronic pain Endoscopic techniques include stenting and lithotripsy Surgery with pancreaticojejunostomy or partial resection may be indicated in refractory cases of CP CP is associated with an increased risk of developing ductal adenocarcinoma, and pancreatic biopsy should be performed if there is concern for a coexisting malignancy Aside from strictures and stones in CP, differential diagnosis of main duct dilation includes neoplasms such as pancreatic ductal adenocarcinoma (PDA) and intrapapillary mucinous cystic neoplasm (IPMN) PDA, neuroendocrine tumor, or metastasis may present as a mass that obstructs the duct Filling defects representing mucinous debris or nodular tumor are occasionally seen in the duct in patients with IPMN However, in the cases of tumor or debris, filling defects are typically not as dark as the signal voids associated with calculi References: Miller FH, Kepke AL, Balthazar EJ Pancreatitis In: Gore RM, Levine MS (eds) Textbook of gastrointestinal radiology, 4th ed Philadelphia, PA: Elsevier/Saunders, 2015:1809–1837 Perez-Johnston R, Sainani NI, Sahani DV Imaging of chronic pancreatitis (including groove and autoimmune pancreatitis) Radiol Clin North Am 2012;50(3):447–466 19a Answer B 19b Answer D.The images shown are a contrast-enhanced CT, gradient-echo T1W in-phase MRI, and gradientecho T1W out-of-phase MRI There is mild hypoattenuation of the pancreatic head on CT On the MR images, there is signal loss on the out-of-phase image (long arrows) compared to the in-phase image This is consistent with microscopic lipid due to focal fatty infiltration, a benign incidental finding in this young patient Comparison with muscle (short arrows) as an internal reference may be helpful when signal loss is more subtle On the inphase image, the pancreatic head is brighter than muscle On the out-of-phase image, the pancreatic head is slightly darker than muscle Fatty infiltration can be more prominent in the anterior pancreatic head, attributed to histologic differences between the embryologic dorsal and ventral pancreas On CT, the hypoenhancing area of fatty infiltration can be mistaken for a pancreatic head adenocarcinoma, but the upstream pancreas (not shown) should be normal without ductal dilation or parenchymal atrophy A lipoma is composed of macroscopic fat, which would lose signal on fat-saturated images, not on outof-phase images Fat- and water-bound protons precess at slightly different frequencies, and their phase shifts can be manipulated to detect microscopic lipid on the T1W GRE in-phase and out-of-phase sequences A pixel that contains a combination of fat- and water-bound protons, such as a pixel within a mass containing microscopic lipid, loses signal during the out-of-phase images (acquired at a TE of about 2.4 msec in a 1.5 tesla magnet) compared to the in-phase images (acquired at a TE of about 4.8 msec) This also occurs as fat–water interfaces, producing the characteristic dark lines of the “India ink,” or “etching,” artifact around the organs surrounded by fat on the outof-phase images No fat saturation has been applied, so macroscopic fat as seen in the mesentery and retroperitoneum remains bright on both sequences These MR images have been performed without contrast, yet artifactual high signal intensity can be seen in the aorta and IVC on some images due to the “entry phenomenon” on gradient-echo sequences Flowing blood moving into the imaging volume is inherently bright on gradient-echo sequences and should not be mistaken for intravascular gadolinium Signal in the IVC will be brightest on the inferior slices of the abdomen as shown here with unsaturated protons coming from below The signal in the aorta will be brightest on the superior slices of the abdomen with the unsaturated protons coming from above References: Duncan SM, Amrhein TJ Chapter 7: Chemical shift type artifact In: Mangrum WI, Christianson KL, Duncan SM, et al (eds) Duke review of MRI principles: case review series Philadelphia, PA: Mosby, 2012:99–110 Kim HJ, Byun JH, Park SH, et al Focal fatty replacement of the pancreas: usefulness of chemical shift MRI AJR Am J Roentgenol 2007;188(2):429–432 Pokharel SS, Macura KJ, Kamel IR, et al Current MR imaging lipid detection techniques for diagnosis of lesions in the abdomen and pelvis Radiographics 2013;33(3):681–702 20 Answer 1C; 2A; 3E; 4B.Pancreatic surgeries may be performed for malignant and benign pathology Pancreatic resection procedures performed for tumor removal include the following: Whipple procedure: Resection of the pancreatic head and part of the duodenum with Roux-en-Y reconstruction Anastomoses are created as follows: from the pancreatic duct and bile duct to the afferent limb; from the stomach (or postpyloric duodenum) to the efferent limb of the jejunum; and from the afferent to efferent limbs of the jejunum to form the common channel Distal pancreatectomy: Removal of the upstream pancreas, usually with splenectomy because of common blood supply from the splenic artery The remaining pancreatic head and neck are oversewn Central pancreatectomy: Removal of a segment of the midpancreas, usually performed for nonaggressive tumors The pancreatic tail is anastomosed to a jejunal loop or the stomach Enucleation: In rare cases, a small, low-grade, peripherally located tumor may be removed while preserving the remainder of the pancreatic tissue Surgery for chronic pancreatitis is performed to improve duct drainage and relieve intractable pain Procedures include the following: Puestow procedure: The dilated pancreatic duct is longitudinally opened from the uncinate process to the tail Ductal calculi are removed The pancreatic duct is anastomosed to the jejunum with a long side-to-side pancreaticojejunostomy Beger procedure: Duodenum-sparing pancreatic head resection, usually to treat head-dominant chronic pancreatitis Frey procedure: Excavation of the pancreatic head preserving the common bile duct, followed by a Puestow procedure Necrosectomy: Debridement of necrotic or infected tissue in necrotizing pancreatitis Pseudocyst derivation: A pseudocyst is internally drained by creating a connection to the stomach or small bowel This can be performed endoscopically, percutaneously, or surgically References: Morgan DE Imaging after pancreatic surgery Radiol Clin North Am 2012;50(3):529–545 Yamauchi FI, Ortega CD, Blasbalg R, et al Multidetector CT evaluation of the postoperative pancreas Radiographics 2012;32(3):743–764 21a Answer C.The pancreas is diffusely enlarged with poorly defined margins, peripancreatic inflammation, and peripancreatic collections The pancreatic body and tail show lack of enhancement, consistent with necrotizing pancreatitis with acute necrotic collection Density of 50% gland necrosis (6 points) for CT severity index (CTSI) of 10 The CTSI score ranges from to 10 as a sum of points derived from the two categories of inflammation and necrosis Scores of to indicate mild disease with little morbidity Scores of to indicate moderate disease Scores of to 10 indicate severe disease with morbidity of >90% and mortality of 17% Balthazar CT Severity Index for Acute Pancreatitis References: Coy DL, Heeter ZR Pancreas In: Lin E, Coy DL, Kanne JP (eds) Body CT: the essentials New York, NY: McGraw-Hill, 2015:131–147 Shyu JY, Sainani NI, Sahni VA, et al Necrotizing pancreatitis: diagnosis, imaging, and intervention Radiographics 2014;34(5):1218–1239 21c Answer B.The acute necrotic collection has developed a thin wall > weeks later and is now described as walled-off necrosis The revised Atlanta criteria for acute pancreatitis redefined collections by time after onset and the presence or absence of necrosis All of the following collections could be further classified as sterile or infected Revised Atlanta Classification of Fluid Collections in Acute Pancreatitis* * Any collection may be either sterile or infected References: Brand M, Götz A, Zeman F, et al Acute necrotizing pancreatitis: laboratory, clinical, and imaging findings as predictors of patient outcome AJR Am J Roentgenol 2014;202(6):1215–1231 Thoeni RF The revised Atlanta classification of acute pancreatitis: its importance for the radiologist and its effect on treatment Radiology 2012;262(3):751–764 22 Answer A.The patient is status post a Whipple procedure The arrows point to a normal-appearing afferent limb at the level of the pancreaticojejunostomy After resection of the pancreatic head and duodenum, the afferent limb of the jejunum is pulled up to the region of the porta hepatis, and anastomoses are performed with the biliary and pancreatic ducts For this reason, it is also called the biliopancreatic limb The blind end of this limb may be demarcated by a staple line, as seen here near the stomach Tubular morphology with thin jejunal folds identifies this as a normal segment of the bowel Occasionally, a decompressed afferent limb may be mistaken for a recurrent mass or an abscess in the porta hepatis The CT below is from the same asymptomatic patient on a different date showing a decompressed normal afferent limb (arrows) The gallbladder is resected has been resected as part of the Whipple procedure and is not present on this image Common complications after Whipple procedure are delayed gastric emptying, wound infection, abscess, hemorrhage, anastomotic leak, peritonitis, and pancreatitis Dilation of the limb may indicate afferent loop syndrome The cause of afferent loop syndrome may be benign or malignant and may or may not be visible on CT References: Morgan DE Imaging after pancreatic surgery Radiol Clin North Am 2012;50(3):529–545 Yamauchi FI, Ortega CD, Blasbalg R, et al Multidetector CT evaluation of the postoperative pancreas Radiographics 2012;32(3):743–764 23a Answer A.This case shows pancreas divisum with the dorsal duct crossing the common bile duct (CBD) toward the minor papilla rather than converging with the CBD at the major papilla The following axial CT image of the pancreatic head in a different patient demonstrates the classic ductal configuration of pancreas divisum, with the duct of Santorini (white arrow) visible as a prominent duct coursing anterior to the common bile duct (black arrowhead) toward the minor papilla On ERCP in another patient, cannulation and contrast injection via the major papilla reveal the characteristic short branching duct (arrows) within the uncinate process that does not communicate with the main duct Pancreas divisum is the most common congenital pancreatic anomaly, found in about 10% of the population There is a failure of fusion of dorsal and ventral pancreatic tissue and ducts As a result, the dorsal pancreatic duct drains most of the pancreatic glandular parenchyma via the accessory duct of Santorini and minor papilla Pancreas divisum is thought to be associated with an increased risk for pancreatitis References: Bret PM, Reinhold C, Taourel P, et al Pancreas divisum: evaluation with MR cholangiopancreatography Radiology 1996;199(1):99– 103 Borghei P, Sokhandon F, Shirkhoda A, et al Anomalies, anatomic variants, and sources of diagnostic pitfalls in pancreatic imaging Radiology 2013;266(1):28–36 23b Answer B.There is focal cystic dilation of the accessory duct of Santorini in the region of the minor papilla consistent with a Santorinicele A Santorinicele may develop due to ductal wall weakness and obstructive physiology in pancreas divisum Divisum exposes the accessory duct to an abnormally increased volume of pancreatic secretions, which may not be adequately drained by the minor papilla While pancreas divisum may be asymptomatic, a subset of patients suffers recurrent bouts of acute pancreatitis due to the obstructive physiology A Santorinicele can contribute to this episodic obstruction Endoscopic sphincterotomy has been found to diminish the Santorinicele, improve flow through the minor papilla, and decrease clinical symptoms Side-branch intraductal papillary mucinous neoplasms are, by definition, within a side branch, not the main duct None of the incorrect answer choices are centered on the duct of Santorini References: Manfredi R, Costamagna G, Brizi MG, et al Pancreas divisum and “santorinicele”: diagnosis with dynamic MR cholangiopancreatography with secretin stimulation Radiology 2000;217(2):403–408 Shirkoda A, Borghei P, Gore RM Chapter 96: Anomalies and anatomic variations of the pancreas In: Gore RM, Levine MS (eds) Textbook of gastrointestinal radiology, 4th ed Philadelphia, PA: Elsevier/Saunders, 2015:1800–1808 24 Answer B.Synthetic secretin may be administered intravenously during MRCP or ERCP to improve distention of the pancreatic ducts Secretin is a hormone normally produced by the duodenum in response to acid, stimulating the pancreas to produce bicarbonate-rich fluid and increasing the tonicity of the sphincter of Oddi A dynamic series of T2W images are obtained over time after secretin injection Structural abnormalities of the duct including strictures, stones, normal variants, and leaks may be better visualized with the improved duct distention after secretin injection Secretin injection also allows semiquantitative assessment of exocrine function, for example, in patients with chronic pancreatitis A greater increase in duodenal fluid volume after secretin injection indicates better preservation of exocrine function After a small test dose, secretin is administered slowly over minute Side effects are uncommon but up to 5% may experience nausea, flushing, and pain Acute pancreatitis is a contraindication Sincalide is the pharmacologic form of cholecystokinin (CCK), which may be infused during Tc-99 m IDA hepatobiliary studies CCK is produced by the duodenum and primarily causes gallbladder contraction facilitating the transit of bile into the duodenum after a fatty meal Sincalide is used after hour if bowel activity is not seen Subsequent bowel activity would indicate normal variation in bile transit rather than true ductal obstruction Sincalide administration also allows for calculation of gallbladder ejection fraction when chronic cholecystitis is suspected Glucagon has a hypotonic effect on bowel and may be administered subcutaneously or intravenously prior to selected gastrointestinal imaging exams at some institutions It decreases bowel spasm, improving distention and patient comfort during double-contrast upper GI, barium enema, CT enterography, and CT colonography Glucagon also decreases bowel motion artifacts on MR enterography Glucagon and insulin are produced by the islet cells of the pancreas to regulate blood glucose levels Glucagon increases and insulin decreases blood glucose References: Sanyal R, Stevens T, Novak E, et al Secretin-enhanced MRCP: review of technique and application with proposal for quantification of exocrine function AJR Am J Roentgenol 2012;198(1):124–132 Tirkes T, Sandrasegaran K, Sanyal R, et al Secretin-enhanced MR cholangiopancreatography: spectrum of findings Radiographics 2013;33(7):1889–1906 25a Answer D.This is a case of autoimmune pancreatitis (AIP) with the classic peripheral halo surrounding the gland AIP is an immune-mediated chronic pancreatitis The three patterns of involvement on imaging are described as diffuse, focal, or multifocal The diffuse pattern is associated with the classic features of AIP, including a peripheral halo as seen in this case, or gland enlargement with effacement of the fatty interstices for a “sausage” appearance as shown in a different patient below Image courtesy of Dr Priya Bhosale, Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX The focal and multifocal patterns of involvement may have mass-like appearance mimicking neoplasm If fibrosis is prominent, delayed enhancement is seen, making distinction from pancreatic ductal adenocarcinoma difficult The halo, if fibrotic, may also demonstrate delayed enhancement MRCP and ERCP reveal a single or multiple long strictures with little to no upstream ductal dilation The common bile duct may be narrowed, causing obstructive jaundice AIP is notably steroid responsive, and findings are potentially reversible with steroid treatment The other answer choices not present with the well-circumscribed halo associated with AIP The pancreas in this case enhances without evidence of necrotizing pancreatitis Lymphoma may present as hypovascular masses or diffuse involvement of the gland with little or no ductal dilation Associated lymphadenopathy may be identified Lymphoma diffusely infiltrating the gland effaces the normal fatty interstices of the gland and may mimic the sausage appearance of AIP However, in the case shown for this question, the parenchymal architecture is relatively well preserved with no evidence of an infiltrating neoplasm References: Khandelwal A, Shanbhogue AK, Takahashi N, et al Recent advances in the diagnosis and management of autoimmune pancreatitis AJR Am J Roentgenol 2014;202(5):1007–1021 Perez-Johnston R, Sainani NI, Sahani DV Imaging of chronic pancreatitis (including groove and autoimmune pancreatitis) Radiol Clin North Am 2012;50(3):447–466 25b Answer A.Autoimmune pancreatitis (AIP) is associated with elevated levels of serum IgG4 Serum IgG4 level >140 mg/dL has been found to be highly sensitive and specific for the diagnosis of AIP, with about 90% accuracy IgG4 may be found in the tissue at FNA/biopsy as well AIP patients may have a lymphoplasmacytic infiltrate of CD4- or CD8-positive lymphocytes and IgG4-positive plasma cells Two types of AIP have been described Type AIP is far more common and accounts for >80% of cases in the United States, with the typical patient >50 years old and male Type AIP is one of the potential manifestations of a multisystemic IgG4-related fibroinflammatory disease Sixty percent of patients with AIP exhibit extrapancreatic signs at presentation Extrapancreatic involvement may include conditions such as retroperitoneal fibrosis, sclerosing cholangitis, sclerosing mesenteritis, orbital pseudotumor, or Riedel thyroiditis Biliary stricturing may resemble primary sclerosing cholangitis Relapse of type AIP occurs often after steroid treatment Type AIP is seen in younger patients with a lower prevalence of IgG4 elevation The pancreas is typically the only organ involved, although there is an association with inflammatory bowel disease in 30% After steroid treatment, type AIP rarely relapses The three patterns of involvement of the pancreas (focal, multifocal, and diffuse) discussed in the previous answer can be seen in both type and type AIP Regarding the other answer choices, CRP (C-reactive protein) is a general indicator of infection or inflammation without specificity for AIP CA19-9 may be elevated in patients with pancreatic and biliary ductal adenocarcinoma, in which case levels can be used to track the disease However, sensitivity and specificity of CA19-9 for malignancy are limited Chromogranin A is a marker associated with neuroendocrine tumors References: Khandelwal A, Shanbhogue AK, Takahashi N, et al Recent advances in the diagnosis and management of autoimmune pancreatitis AJR Am J Roentgenol 2014;202(5):1007–1021 Perez-Johnston R, Sainani NI, Sahani DV Imaging of chronic pancreatitis (including groove and autoimmune pancreatitis) Radiol Clin North Am 2012;50(3):447–466 26 Answer D.Collections related to pancreatitis may require drainage if determined to be symptomatic The CT scan revealed a pseudocyst near the pancreatic tail which was thought to be contributing to the patient’s symptoms of pain and weight loss In this case endoscopic pseudocyst derivation was performed with placement of stents allowing drainage of cyst contents into the stomach If percutaneous drainage is performed, CT is preferred over transabdominal ultrasound for guidance because bowel and other surrounding critical structures are better visualized and avoided A multidisciplinary approach including a combination of percutaneous, endoscopic, and surgical techniques may be required for adequate management Surgery is considered if less invasive approaches are unsuccessful The natural course of most acute peripancreatic fluid collections (APFCs) is spontaneous resolution, and drainage is not required in most cases Patients with necrosis are at higher risk of infection, with walled-off necrosis more likely to be infected than pseudocysts An infected collection is associated with high morbidity and requires drainage Unfortunately, CT does not reliably distinguish sterile from infected collections Fewer than 25% of infected collections in patients with pancreatitis contain gas The presence of gas in a collection is highly suspicious for infection, although occasionally gas may also be seen if the collection has fistulized to bowel Fineneedle aspiration may be required to diagnose infection Asymptomatic sterile collections may not require intervention References: Coy DL, Heeter ZR Pancreas In: Lin E, Coy DL, Kanne JP (eds) Body CT: the essentials New York, NY: McGraw-Hill, 2015:131–147 Shyu JY, Sainani NI, Sahni VA, et al Necrotizing pancreatitis: diagnosis, imaging, and intervention Radiographics 2014;34(5):1218–1239 27 Answer C.This mass in the pancreatic body enhances on arterial phase greater than venous phase, consistent with a hypervascular neoplasm The left kidney has been resected (The tail is extending into the nephrectomy site.) Renal cell carcinoma (RCC) is the most common metastasis to the pancreas and often appears as a hypervascular mass RCC accounts for 30% of metastases to the pancreas, followed by lung cancer Breast, colorectal, and melanoma metastases are also seen Metastases to the pancreas represent 2% to 5% of pancreatic malignancies, with variable appearance They can present as a solitary mass, multiple masses, or diffuse infiltration The duct may be normal or obstructed, whereas pancreatic ductal adenocarcinoma being desmoplastic tends to cause duct obstruction even if the tumor is small Patients can be asymptomatic or exhibit nonspecific symptoms such as pain or weight loss While most other metastases develop within years of primary tumor diagnosis, RCC metastases typically arise to 12 years after initial presentation The main differential diagnosis for this solitary hypervascular mass is a pancreatic neuroendocrine tumor Melanoma metastasis and small cell lung cancer (considered a neuroendocrine tumor) may be hypervascular but are less common in the pancreas than RCC Lymphoma and most other metastases are hypovascular Secondary involvement of the pancreas in lymphoma is seen in up to 30% of patients with extensive non-Hodgkin lymphoma and is more common than primary pancreatic lymphoma References: Klein KA, Stephens DH, Welch TJ CT characteristics of metastatic disease of the pancreas Radiographics 1998;18(2):369–378 Low G, Panu A, Millo N, Leen E Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas Radiographics 2011;31(4):993–1015 28a Answer C 28b Answer D.Contrast-enhanced axial CT shows a collection in the region of the pancreatic head Its density is greater than that of simple fluid, and centrally, there is a well-circumscribed round focus of enhancement similar to aortic density Findings likely represent a pseudoaneurysm with surrounding hemorrhage, and angiography is the most appropriate next step in this hemodynamically-stable patient Selective superior mesenteric arteriogram demonstrates a round, smoothly-marginated vascular blush arising from a branch of the vessel which correlates with the CT enhancement, confirming a pseudoaneurysm Treatment is embolization Regarding vascular blushes, dynamic imaging can distinguish pseudoaneurysm (which demonstrates washout) from active hemorrhage (which grows and disperses) Severe acute pancreatitis can be complicated by vascular abnormalities secondary to enzymatic digestion or infection of the vascular wall Pseudoaneurysms occur in up to 10% of patients with acute pancreatitis The arteries most commonly affected are the splenic artery (40%) and gastroduodenal artery (30%) The hepatic, superior mesenteric, and left gastric arteries may also be affected Thrombosis is another vascular complication of pancreatitis Splenic vein thrombosis seen in 10% to 40% of patients with acute pancreatitis, and thrombosis of the portal vein may also occur References: Balthazar EJ Acute pancreatitis: assessment of severity with clinical and CT evaluation Radiology 2002;223:603–613 Merkle EM, Görich J Imaging of acute pancreatitis Eur Radiol 2002;12:1979–1992 O’Conner O, Buckley JM, Maher MM Imaging of the complications of acute pancreatitis AJR Am J Roentgenol 2011;197:w375–w381 ... findings in 27 patients Dysphagia 2003 ;18 (1) :9 15 Foltz C, Strum W Images in clinical medicine Epiphrenic diverticulum N Engl J Med 2 014 ;3 71( 26):2 510 11 Answer D.The barium esophagram demonstrates... clinicopathologic findings Am J Surg Pathol 20 01; 25(9) :11 80 11 87 Bleshman MH, Banner MP, Johnson RC, et al The inflammatory esophagogastric polyp and fold Radiology 19 78 ;12 8(3):589–593 Answer C.Right anterior... among patients with Barrett’s esophagus N Engl J Med 2 011 ;365 (15 ) :13 75 13 83 Rustgi AK, El-Serag HB Esophageal carcinoma N Engl J Med 2 014 ;3 71( 26):2499–2509 6 Answer C.The finding is a fixed, thickened