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ABSTRACT |
Katz D. S.4; Merunka V.4; Fantauzzi J. P.4; Hines J. J.1; Mazzie J. P.3; Sadler M.3; Meiner E. M.2; Weston S. R.4 1. Long Island Jewish Medical Center, New Hyde Park, NY; 2. North Shore University Hospital, Manhasset, NY; 3. St. Vincent's Catholic Medical Center, New York, NY; 4. Winthrop–University Hospital, Mineola, NY
Address correspondence to D. Katz (dsk2928{at}pol.net)
Background: To demonstrate the spectrum of presentation of less common, atypical, and rare presentations of appendicitis on CT, and to review in detail the clinical and CT literature on these presentations.
Key Issues: With the increasing use of CT for imaging patients with acute abdominal and pelvic disorders, radiologists need to be familiar with the spectrum of less common and rare presentations of acute appendicitis.
Format: The following presentations of appendicitis on CT will be shown, and the corresponding CT, surgical, and pathologic literature will be reviewed: early appendicitis, tip appendicitis, resolving appendicitis, stump appendicitis, gangrenous appendicitis, appendiceal abscess, extruded appendicolith, free gas related to appendicitis, foreign body appendicitis, barium appendicitis, Amyand's hernia and its variants, left-sided appendicitis, appendicitis secondary to tumor, and appendicitis secondary to adjacent infectious and inflammatory processes.
Teaching Points: Radiologists need to be familiar with the broad spectrum of uncommon, unusual, and rare variants/presentations of appendicitis, as may be identified on CT, and the implications for appropriate patient management.
E157. Is it Appendicitis? Pitfalls in the CT Evaluation of Women with Right Lower Quadrant Pain
Chong L.; Poh A.; Tan A. Changi General Hospital, Singapore
Address correspondence to L. Chong (lrchong{at}pacific.net.sg)
Background: CT has been established as a reliable and highly accurate tool in the diagnosis of acute appendicitis. Nevertheless, numerous imaging pitfalls exist, particularly in women, which may result in the wrong diagnosis. In addition to other bowel pathology (e.g., diverticulitis), acute gynecological disorders such as torsion, endometriosis, ruptured ovarian cyst and tuboovarian abscess may look similar to appendicitis or appendiceal abscess. Conversely, secondary inflammation of the adnexa from an adjacent appendicitis may inadvertently lead the radiologist to the diagnosis of pelvic inflammatory disease. This exhibit demonstrates these and the potential radiological pitfalls, and includes important points for the accurate diagnosis of appendicitis.
Key Issues: 1. To describe and illustrate the CT features of conditions in women that may mimic appendicitis, with an emphasis on acute gynecological disorders. 2. To describe and illustrate examples of appendicitis mimicking acute gynecological disorders. 3. To emphasize the important points for the accurate diagnosis of acute appendicitis.
Format: This will be in the form of a didactic exhibit demonstrating the various pathological processes and imaging pitfalls that may mimic appendicitis on CT.
Teaching Points: 1. Not all right lower quadrant pain in women is due to acute appendicitis. 2. Acute gynecological disorders can mimic appendicitis and vice versa. 3. Rigorous identification and evaluation of the appendix is of paramount importance in every case of suspected appendicitis.
E158. Etiology of Abnormal Appearing Appendices Simulating Appendicitis in Patients with Abdominal Pain
Walsh M. A.; Cohan R. H.; Francis I. R.; Daly C. P.; Caoili E. M. University of Michigan, Ann Arbor, MI
Address correspondence to M. Walsh (walshma{at}med.umich.edu)
Objective: To determine the frequency with which etiologies other than appendicitis are responsible for abnormal appearing appendices on abdominal and pelvic CTs performed on patients with right lower quadrant pain.
Materials and Methods: Of 1361 patients referred for CT with suspected appendicitis, 207 were diagnosed with conditions other than acute appendicitis. Of these, 15 patients with an abnormal appearing appendix on CT subsequently underwent surgery. Final pathologic diagnosis was correlated with imaging findings in these 15 patients.
Results: A number of diseases other than appendicitis were responsible for abnormal appearing appendices, including Crohn's disease (n = 2), ulcerative colitis (n = 1), periappendicitis (n = 1), secondary involvement of the appendix due to serositis (n = 2), fibrous obliteration of the appendix (n = 1), serositis with periappendiceal fat necrosis (n = 1), a fecolith (n = 2) and endometriosis involving the appendix (n = 1). Neoplasia was found in two patients, including appendiceal cystadenoma (n = 1) and carcinoid (n = 1). In two patients no pathologic abnormality was identified in the appendix, despite the abnormal imaging findings.
Conclusion: Diseases other than appendicitis can simulate appendicitis in patients undergoing CT due to right lower quadrant pain.
E159. Multiphasic Examination of the Esophagus: Standard and Supplemental Techniques
Ye B.; Ott D.; Chen M. Wake Forest University Medical School, Winston Salem, NC
Address correspondence to B. Ye (brendaye{at}yahoo.com)
Background: Radiographic examination of the esophagus remains useful in evaluating a wide variety of patient complaints, particularly the symptom of dysphagia. For these complaints, a thorough examination of the pharynx and esophagus is warranted, and radiologists need to maintain their fluoroscopic skills and be familiar with the variety of techniques used to evaluate patients effectively with swallowing difficulties.
Key Issues: At our institution, a multiphasic examination is performed which includes functional and structural evaluation of the pharynx and esophagus. Pharyngeal and esophageal function is assessed by rapid-sequence motion recording and fluoroscopic observation on remote-control equipment. Structural evaluation is done using double-contrast, full-column, and mucosal relief techniques. In addition, supplemental techniques for examining the esophagus are also reviewed; these latter techniques include the use of `iced' barium, solid boluses such as marshmallow portions, assessment for esophageal varices, and approaches for relief of food impaction.
Format: This exhibit will be a didactic and pictorial presentation outlining and illustrating the multiphasic esophageal examination of the pharynx and esophagus as performed at our medical center. A wide variety of pharyngeal and esophageal abnormalities are illustrated and the appropriate techniques for their evaluation and the efficacy of these methods discussed.
Teaching Points: 1. Describe the diagnostic techniques used for radiographic examination of the pharynx and esophagus. 2. Select an appropriate supplemental technique for evaluating specific esophageal problems, such as the indication for use of a marshmallow portion. 3. State the efficacy of the various esophageal techniques for various esophageal disorders.
E160. Normal and Abnormal Appearances of the Jejunum at CT Enterography with Comparison to Barium Exams and Endoscopy
Silva A.2; Hara A.2; Menias C.1 1. Mallinckrodt Institute of Radiology, St. Louis, MO; 2. Mayo Clinic, Scottsdale, AZ
Address correspondence to A. Silva (silva.alvin{at}mayo.edu)
Background: The jejunum is a difficult area to evaluate both radiographically and endoscopically due to its location, tortuosity and dense mucosal fold pattern. Advances in endoscopic, CT and MR technology and new oral contrast agents, however, have improved evaluation and detection of disease in this challenging area.
Key Issues: The purpose of this exhibit is to describe advances in imaging techniques of the small bowel and to present the imaging characteristics of disease specifically in the jejunum, an area where disease is commonly misdiagnosed or overlooked. First, the rationale for various oral contrast and scanning techniques of both CT Enterography (CTE) and MR Enterography (MRE) with correlative imaging will be explained. The variable normal appearance of the jejunum will be demonstrated followed by imaging examples with endoscopic correlation of inflammatory, malignant and vascular diseases involving the jejunum. Examples to be shown include: Celiac disease, Crohn's disease, scleroderma, Henoch-Schonlein purpura, diverticulitis, foreign body perforation, ulcer, intussusception, adenocarcinoma, carcinoid, lymphoma, GIST, metastases, arteriovenous malformation, active hemorrhage, and intramural hematoma. Differential diagnostic characteristics of these disease processes will be discussed.
Format: The format will be primarily didactic with a summary of key points and a self-test at the end. It will start with imaging technique followed by imaging examples separated by pathologic process (inflammatory, malignant and vascular diseases).
Teaching Points: 1. To become familiar with advances in oral contrast and scanning techniques for the small bowel using CTE and MRE. 2. To become familiar with the variable imaging features and enhancement characteristics of the normal jejunum depending on distention and contrast timing. 3. To identify the imaging characteristics of various inflammatory, malignant and vascular disease of the jejunum.
E161. CT Enterography (CTE) for Evaluation of Inflammatory Bowel Disease: How, When, Why?
Rezvani M.; Yaghmai V.; Siddiqi A. J.; Hammond N.; Miller F.; Nikolaidis P. Northwestern University–Feinberg School of Medicine, Chicago, IL
Address correspondence to M. Rezvani (m-rezvani{at}northwestern.edu)
Background: CT enterography (CTE), using VoLumen, a neutral oral contrast agent, and multislice CT, is gaining acceptance as an accurate and efficient imaging method for evaluation of patients with inflammatory bowel disease (IBD). CTE has several distinct advantages over SBFT that will be reviewed in this exhibit.
Key Issues: 1. Review of CTE technique and protocol. 2. Review of optimal image interpretation methodology (combination of axial, MPR and MIP images). 3. Examples of cases where CTE offers additional important information over SBFT (e.g., evaluation of overlapped bowel loops, assessment of disease activity, evaluation of extent of disease, extraintestinal findings relevant to management of IBD). 4. A brief discussion of limitations of CTE will also be included.
Format: The format is didactic. The temporal organization of the exhibit will lead the reader through study indications, patient preparation, image acquisition and interpretation.
Teaching Points: 1. CTE is an efficient method for comprehensive evaluation of patients with IBD. 2. CTE offers several advantages over SBFT that make it the ideal primary method for diagnosing IBD and its complications.
E162. Multislice CT Enterography (CTE): Spectrum of Findings in Crohn's Disease
Yaghmai V.; Rezvani M.; Hammond N.; Siddiqi A. J.; Miller F.; Nikolaidis P. Northwestern University - Feinberg School of Medicine, Chicago, IL
Address correspondence to V. Yaghmai (v-yaghmai{at}northwestern.edu)
Background: CT enterography is a noninvasive and sensitive method of examining the gastrointestinal tract. It has distinct advantages over the small bowel follow through (SBFT) examination. We present our experience with this imaging technique when evaluating patients with Crohn's disease.
Key Issues: The spectrum of intestinal as well as extraintestinal findings in CTE of patients with Crohn's disease will be discussed. These include both acute as well as chronic manifestations of Crohn's including acute mucosal inflammation and mural stratification, transmural ulceration, strictures, fistulas, sinus tracts, abscess formation, submucosal and mesenteric fat deposition, and lymphadenopathy. Comparison with SBFT studies will be made in order to demonstrate the advantages of CTE. Imaging techniques and pitfalls will also be discussed.
Format: The format is didactic. The exhibit will be organized according to the pathologic findings in Crohn's disease.
Teaching Points: CTE using neutral oral contrast material is a simple and comprehensive method of evaluating both the intestinal and extraintestinal manifestations of Crohn's disease. CTE should be the initial imaging modality of choice for evaluation of these patients.
E163. MR Enterography of Small Bowel Crohn's Disease–Spectrum of Findings
Lee W.; Seale M.; Kalade A.; Smith P.; Lui B.; Taylor A.; Desmond P. St. Vincent's Hospital, University of Melbourne, Fitzroy, Australia
Address correspondence to W. Lee (leewk33{at}hotmail.com)
Background: Crohn's disease is a chronic noncaseating granulomatous inflammatory condition of the bowel that predominantly affects young adults. The small bowel, especially the terminal ileum, is the most commonly involved. Crohn's disease is characterized by episodes of acute exacerbation and remission. Clinical indices, such as Crohn's disease activity index, have been developed to provide an estimate of the severity of disease. Imaging has an important role in detecting small bowel disease, assessing its extent and identifying associated complications. Many of the commonly used current radiologic techniques to assess small bowel Crohn's disease involve ionizing radiation. The cumulative radiation dose to these young patients is a concern. Current state-of-the-art MR techniques allow small bowel imaging with minimal artifact and relatively good resolution, but without ionizing radiation.
Key Issues: A search of the authors' institutional database for cases of small bowel Crohn's detected at MR enterography from March 2005 to September 2006 was performed. Transmural abnormalities (linear ulcers, mural thickening, skip lesions and pseudodiverticula), extramural abnormalities (sinus tracts, fistula, abscess, phlegmon, fibrofatty proliferation, mesenteric hypervascularity and mesenteric adenopathy) and extraenteric manifestations are shown in a pictorial review.
Format: A didactic pictorial review illustrating the spectrum of findings of small bowel Crohn's disease at MR enterography is presented.
Teaching Points: 1. To appreciate the strengths and weaknesses of the MR sequences commonly used to assess small bowel. 2. To be familiar with the MR enterography appearances of small bowel Crohn's disease.
E164. MRI of the Small Bowel: Techniques, Applications and Limitations
Sebastian S.; Lauenstein T.; Martin D. Emory University School of Medicine, Atlanta, GA
Address correspondence to S. Sebastian (Sunit.Sebastian{at}emoryhealthcare.org)
Background: The small bowel follow-through examination is widely accepted as the primary imaging method for small bowel investigation. The introduction of fast magnetic resonance imaging (MRI) sequences has evoked an increasing interest in the use of MRI for small bowel evaluation. Inherent advantages of small bowel evaluation include lack of ionizing radiation and the ability to provide additional extraluminal information. Moreover, excellent soft tissue contrast and direct multiplanar reformations further enhance the diagnostic capabilities of MRI for small bowel diseases.
Key Issues: In this exhibit we will use suitable illustrations, images and video clips to: 1] Review the current techniques and clinical applications of MRI for the evaluation of patients with a spectrum of small bowel diseases. 2] Address limitations of MRI evaluation of the small bowel. 3] Summarize advantages/disadvantages of MRI vs. conventional techniques
Format: 1. Introduction 2. Clinical indications 3. Protocols 4. MR Enteroclysis 5. Advantages, disadvantages and importance of each technique
Teaching Points: 1. Clinical indications, advantages and limitations of MRI imaging of the small bowel with the help of suitable tables, illustrations, images and video clips. 2. The current status of MRI of the small bowel imaging with advantages and disadvantages relative to computed tomography and other imaging techniques.
E165. Pseudomembranous Colitis: Etiology, Pathology, and Imaging
Ye B.; Ott D.; Oliphant M.; Chen M. Wake Forest University Medical School, Winston-Salem, NC
Address correspondence to B. Ye (brendaye{at}yahoo.com)
Background: Pseudomembranous colitis is an important colonic inflammatory disease. Because the cause is often specific, the condition can be treated; imaging findings may mimic other forms of colitis. Pseudomembranous colitis is being diagnosed with increasing frequency and the majority of cases in recent decades are associated with antibiotic exposure; however, the disorder may resemble other acute colonic and intestinal diseases making early recognition and differential diagnosis crucial.
Key Issues: Pseudomembranous colitis is typically an antibiotic related colonic inflammation due to overgrowth of Clostridium diffi cile. The toxin released by this organism causes mucosal inflammation, necrosis, and pseudomembranes. The etiology and pathology of this disease is discussed in detail and the newest research into its current understanding reviewed. Pseudomembranous colitis can be detected on endoscopic, contrast enema, and cross-sectional imaging examinations. Plain films of the abdomen may also suggest the disease, but CT imaging has been particularly useful in its diagnosis and in determining the extent of colonic involvement. The imaging findings on CT scanning are emphasized since this examination is often used early in patients with suspected acute abdominal presentations.
Format: This exhibit will be a didactic and pictorial presentation of pseudomembranous colitis discussing the etiology and pathology of the disease and illustrating the multiple imaging features with an emphasis on CT examination. In addition, other colonic conditions which may mimic this colitis will also be reviewed and illustrated to demonstrate the usefulness of imaging in the differential diagnosis of patients with acute colonic problems.
Teaching Points: 1. Acquire an updated understanding of the etiology and pathology of pseudomembranous colitis. 2. Describe the types of imaging used in evaluating this disease and the findings that suggest the presence of pseudomembranous and other types of colitis. 3. Identify the differential considerations on imaging evaluation between pseudomembranous colitis and other similar disorders.
E166. The Role of CT in the Diagnosis of Pseudomembranous Colitis
Lipstein H.; Medina A.; Chermak R. Mt. Sinai Medical Center, Miami Beach, FL
Address correspondence to H. Lipstein (hlipstei{at}msmc.com)
Background: Pseudomembranous colitis is a commonly occurring complication of antibiotic therapy. A potentially life-threatening disease with overall mortality rates reported between 1.1–3.5%, pseudomembranous colitis is a rising cause of clinical concern in the inpatient setting. Caused by the production of large amounts of toxin A and B by the gram positive bacillus, Clostridium diffi cile, the resulting colitis is the fourth most common nosocomial disorder reported to the CDC. Patients who are at greatest risk for developing this condition include: the elderly, those in the ICU, uremic patients, patients who have undergone recent surgery, especially abdominal surgery and cancer patients. The diagnosis of C. diffi cile colitis is made by stool assay for Toxin B. Although this is a highly sensitive test (95% sensitivity), it requires two days for diagnosis. A quicker, albeit less sensitive alternative is an ELISA assay for Toxin A, with a 75–85% sensitivity. Visualizing the yellow plaques on proctosigmoidoscopy or colonoscopy is definitive, however these studies are contraindicated in severe cases. C. diffi cile colitis has a wide spectrum of presenting symptoms ranging from mild diarrhea to an acute abdomen and sepsis-like picture. Given the varied clinical picture, the role of the radiologist is becoming increasingly important in the early detection. CT, although not specific, may be the first indication of the disease. Several findings are suggestive of the condition and therefore the radiologist may be essential in preventing unnecessary interventions and progression to fatal complications.
Key Issues: The CT findings that are more suggestive of C. diffi cile colitis, including marked wall thickening and edema, relative paucity of pericolonic fat stranding in relation to the degree of bowel inflammation, "the target sign," " the accordian sign," and ascites will be presented.
Format: The presentation will be in didactic format. Examples of each of the radiologic signs will be discussed and demonstrated along with pathologic correlation. In addition, examples of other colitides for comparison will be presented.
Teaching Points: 1. Understanding the role of CT in the diagnosis of pseudomembranous colitis. 2. Upon completion, the viewer will have a better grasp of the CT findings suggestive of C. diffi cile colitis, and a better ability to differentiate pseudomembranous colitis from other colitides.
E167. The Effect of Polyp Size, Polyp Morphology, and Diagnostic Confidence on Positive Predictive Value at Screening CT Colonography
Prout T. M.; Pickhardt P. J.; Kim D. H. University of Wisconsin Hospital and Clinics, Madison, WI
Address correspondence to T. Prout (TProut{at}uwhealth.org)
Objective: To evaluate factors affecting positive predictive value
(PPV) for polyps 
6 mm detected at screening CT colonography (CTC).
Materials and Methods: 397 (12.8%) of 3112 consecutive patients
undergoing CTC screening at a single institution were prospectively called
positive for polyps 6 mm, consisting of 542 total lesions. 244 patients
with 363 CTC-detected lesions were evaluated at subsequent optical colonoscopy
(OC); the remaining 179 polyps (all 6–9 mm) in 153 patients enrolled in
short-term CTC surveillance were necessarily excluded from analysis. PPV was
derived from OC findings: CTC true positive = matched polyp at OC; false
positive = not found at OC. PPVs were further analyzed in terms of the
prospective CTC polyp size (6–9 mm and 10 mm), morphology
(pedunculated, sessile, and flat), and diagnostic confidence of the CTC
finding (3 = most confident, 1 = least confident).
Results: The overall PPV for CTC-detected lesions 6 was 88.4%
(321/363). PPV according to size was 87.8% (173/197) for 6–9 mm lesions
and 89.1% (148/166) for lesions 10 mm (p = 0.667). PPV according
to morphology was 94.3% (66/70) for pedunculated, 91.1% (215/236) for sessile,
69.2% (36/52) for flat lesions. Of note, combined sessile and pedunculated
morphology more often yielded a matching lesion at OC than flat lesions (91.8%
[281/306] vs. 69.2% [36/52]; p < 0.001). PPV according to
diagnostic confidence was 91.5% (258/282) for most confidence (score of 3),
88.1% (52/59) for intermediate confidence (score of 2), and 57.1% (8/14) for
least confidence (score of 1). Of note, combined level 3 and 2 confidence more
often yielded a matching neoplasm at OC than level-1 confidence lesions (90.1%
[310/341] vs. 57.1% [8/14]; p < 0.001).
Conclusion: High concordance for CTC-detected lesions at
subsequent OC results in an overall PPV of nearly 90% for our CTC screening
program. Increased diagnostic confidence and a pedunculated or sessile polyp
morphology correlate with a higher likelihood of finding a matching polyp at
OC, whereas polyp size (6–9 mm vs. 10 mm) had surprisingly little
effect on PPV.
E168. MR Colonography: Ecce Signum (Behold the Proof)
Sebastian S.; Lauenstein T.; Martin D. Emory University School of Medicine, Atlanta, GA
Address correspondence to S. Sebastian (Sunit.Sebastian{at}emoryhealthcare.org)
Background: Magnetic resonance colonography (MRC) is one of the two methods used for performing virtual colonoscopy, the other being CT colonography. There are widely accepted indications for MRC and its use is slowly growing in clinical practice for the evaluation of the large bowel. MRC is increasingly being propagated as a screening tool, due to its inherent advantages like noninvasiveness of the technique and the lack of ionizing radiation. Moreover, MR colonography is a feasible and useful method for evaluating the entire colon in patients with an incomplete conventional colonoscopy. Recent papers have proven that MRC has high diagnostic accuracy and outstanding patient acceptance. However, in spite of all its advantages MRC is still available only in select specialized centers.
Key Issues: This educational exhibit will describe in detail the technical requirements for MR colonography. Several images and video clips will be used to explain the advantages, disadvantages and limitations of the technique. The impact of fecal tagging concepts is discussed
Format: Didactic, interactive content organization 1. Introduction 2. Clinical indications 3. Protocols 4. Advantages, disadvantages and importance 5. Clinical outcomes 6. Future improvements in fecal tagging strategies
Teaching Points: This exhibit will review: 1. Various technical requirements for MR colonoscopy and methods of data acquisition and image interpretation with the help of several illustrations, figures and video clips. 2. Advantages, drawbacks and artifacts related to MR colonoscopy. 3. Probable future improvements in fecal tagging strategies to avoid bowel cleansing.
E169. Diverticulitis: Common and Uncommon Manifestations of a Common Disease in Oncology Patients
Verma R.; Iyer R. B.; Silverman P. M.; Dunnington J. S.; Charnsangavej C.; DuBrow R. A. MD Anderson Cancer Center, Houston, TX
Address correspondence to R. Verma (Rajiv.Verma{at}di.mdacc.tmc.edu)
Background: Diverticulitis is a common inflammatory condition of bowel, which predominantly affects the sigmoid colon. In the appropriate clinical setting, CT features are diagnostic. In oncology patients, diverticulitis may present specific diagnostic challenges. History of prior surgeries, masking effect of steroids, immunocompromised status and presence of adjacent malignancy often present dramatic imaging appearances with possible lack of clinical signs and symptoms.
Key Issues: Unusual CT findings of diverticulitis in oncology patients may include: atypical locations such as small bowel or other colonic sites; atypical distribution of free air in the peritoneum, retroperitoneum or both; fistulae to various sites.
Format: Interactive display of different imaging studies which will describe the spectrum of imaging findings that may be encountered in oncology patients with diverticulitis. Discussion will include epidemiology and pathophysiology as well as relation with different malignancies like leukemias, lymphomas and bowel malignancies. In addition a discussion of imaging protocols, role of CT, diagnostic features and techniques in CT as well as the role of alternative imaging modalities will be included. Specific clinical and diagnostic issues in diagnosis and management of diverticulitis in oncology patients will also be discussed.
Teaching Points: 1. Recognizing unusual presentations in patients with known malignancy. 2. Unusual distribution of air collections in patients with perforation. 3. Differential diagnosis of inflammatory conditions in oncology patients with similar presentations like typhlitis, appendicitis. 4. Importance of clinical history and presentation, in narrowing the differential diagnosis.
E170. Imaging Manifestations of Meckel's Diverticulum
Elsayes K. M. 2; Harvin H. J.1; Menias C. O.1; Francis I. R. 21. Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO.; 2. University of Michigan Health Center, Ann Arbor, MI
Address correspondence to K. Elsayes (kelsayes{at}med.umich.edu)
Background: Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract. It is seen in 2% of the population, and it is caused by failure of the omphalomesenteric duct to regress. The point of attachment of a Meckel's diverticulum to the bowel varies. Most (75%) Meckel's diverticula are found within 100 cm of the ileocecal valve. Meckel's diverticulum occurs with equal frequency in both sexes, but symptoms from complications are more common in male patients. Meckel's diverticula are typically asymptomatic and usually are found incidentally, with a lifetime risk of complications reported as being 4%–40%. Heterotopic gastric and pancreatic mucosa are frequently found histologically within the diverticula of symptomatic patients. The most common complications are hemorrhage from peptic ulcer-ation, small intestinal obstruction, and diverticulitis. The purpose of this exhibit is to familiarize the radiologist with the current imaging of Meckel's diverticulum as well as its presenting complications. The spectrum of diagnostic findings on various imaging modalities will be reviewed.
Key Issues: 1. Embryology and anatomy. 2. Imaging findings and utility of various imaging modalities; plain radiographic examination, conventional barium studies, ultrasonography, computed tomography, angiography and scintigraphy. 3. Imaging of complications of Meckel's diverticulum; hemorrhage, bowel obstruction, enterolith formation, inflammation, neoplasm and perforation.
Format: Organizational structure (by embryology, by imaging techniques, findings and complications).
Teaching Points: 1) To describe the anatomy and embryology of Meckel's diverticulum. 2) To review the utility of various imaging modalities for diagnosing Meckel's diverticulum. 3) To illustrate the imaging findings of Meckel's diverticulum and its complications.
E171. The Ins and Outs of Intussusception
Cook H. J.; Tao H. The University of Ottawa, Ottawa, Canada
Address correspondence to H. Cook (bcook002{at}sympatico.ca)
Background: Intussusception occurs when a proximal bowel segment (intussusceptum) telescopes or invaginates into a distal bowel segment (intussuscipiens). It is the second most common abdominal emergency in the pediatric population, but a rare cause of abdominal emergency in adults. The etiology of intussusception varies not only by patient age but bowel location involved. Approximately two-thirds of adult cases occur in the small bowel where the etiology is more commonly benign, whereas the etiology in the large bowel is more commonly malignant. Intussusception as an incidental finding is now more frequently encountered with the advent of cross-sectional imaging. This raises the question of what to do with the incidentally encountered intussusception. The concept of self-limiting intussusception has been introduced. Studies have looked at characteristics to differentiate self-limiting from non self-limiting intussusception requiring surgery for bowel compromise.
Key Issues: Approximately twenty cases of intussusception were reviewed for clinical presentation, length of intussusception, lead point, and outcome (surgical vs. nonsurgical management). The cases will be used to highlight the etiology, anatomy, and imaging features of intussusception. The cases will demonstrate characteristics of self-limiting vs. non self-limiting intussusception as presented in the literature.
Format: The exhibit will be in a self-paced, interactive format, with an interactive quiz to highlight the key teaching points. Images from the reviewed cases will demonstrate the etiologies, pathophysiology, multimodality imaging appearances and characteristics suggesting self-limiting vs. non self-limiting intussusception. Many of the cases include multiple imaging modalities to highlight the spectrum of imaging appearances. Follow-up on each case will be provided to correlate with imaging characteristics.
Teaching Points: The pathophysiology of intussusception. The reader will gain an understanding of the bowel wall layers involved in the intussusceptum and intussuscipiens. The most common lead points based on bowel segment involved. The characteristic radiographic, fluoroscopic barium study, CT and ultrasonographic imaging appearances of intussusception. The imaging characteristics that help differentiate self-limiting vs. non self-limiting intussusception.
E172. Magnetic Resonance Imaging of the Gall Bladder; Spectrum of Abnormalities
Elsayes K. M.2; Oliveira E. P.1; Narra V. R.1; El-Merhi F.3; Brown J. J.1 1. Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO.; 2. University of Michigan Health Center, Ann Arbor, MI; 3. University of Texas Health Center, San Antonio, TX
Address correspondence to K. Elsayes (kelsayes{at}med.umich.edu)
Background: The gallbladder is affected by a variety of pathologic conditions that are often associated with nonspecific signs and symptoms. Imaging plays an important role in determining the nature of the pathologic condition and in guiding appropriate therapy. Real-time ultrasonography is the most widely used diagnostic study for the gallbladder and the primary screening examination of choice. CT or MRI is often used for further evaluation when clinical questions persist after ultrasonography has been performed. MRI of the gallbladder typically includes a set of MR cholangiopancreatography (MRCP) pulse sequences. Understanding the patterns of various disease manifestations on MRI and MRCP is the key to make an accurate diagnosis. This exhibit discusses techniques for optimizing MR imaging of the gallbladder and describes the MRI features of several of the more important disease processes that involve the gallbladder.
Key Issues: 1. MR Technique. 2. Pathology and imaging findings of various gallbladder diseases such as; congenital (agenesis and duplication), inflammatory (acute, hemorrhagic, chronic and xanthogranulomatous cholecystitis), benign tumors (polyps, cystadenoma and adenomyomatosis), malignant tumors (carcinoma, lymphoma) and miscellaneous (cholelithiasis, Mirizzi syndrome).
Format: Organizational structure (by anatomy, MR imaging technique, pathology and imaging findings)
Teaching Points: 1. To describe the MR imaging features of various gall bladder diseases. 2. To review the utility of MR imaging technique in diagnosis and characterization of various gall bladder pathologies.
E173. Rectal Cancer: Local Staging Using Combined Pelvic Phased-Array and Endorectal Coil MRI
Radwan S. M.3; Salem H.1; Ziada S.2; Rizk H.31. Faculty of Medicine, Cairo University, Cairo, Egypt; 2. Faculty of Medicine, Alazhar Univeristy, Cairo, Egypt; 3. Theodor Bilharz Research Institute, Giza, Egypt
Address correspondence to S. Radwan (shradwan{at}hotmail.com)
Objective: We evaluate the role of MR imaging using pelvic phased array coil alone and both pelvic phased array and endorectal coils in the diagnosis and staging of rectal carcinoma.
Materials and Methods: This study was approved by our institutional review board for human investigation. 50 consecutive patients (30 men and 20 women) with primary rectal cancer were examined with either pelvic alone or pelvic and endorectal MRI for the preoperative evaluation of tumor extent. The results of examinations were compared with the histology of resected specimens. The sensitivity, specificity and accuracy of combined endorectal and pelvic MRI and pelvic MRI alone in identifying the depth of tumor penetration and the number of regional lymph nodes were calculated.
Results: Considering T3 staging, our study showed that MRI is 92% accurate while, it was 94% accurate in the assessment of pelvic organ infiltration (T4). The overall accuracy for T staging was 90%. Also in the assessment of perirectal lymph node enlargement MRI was proved to have high accuracy, (86%) as compared to the postoperative pathological results. On comparing the results of the two different techniques used in this work, we found no significant difference in relation to the postoperative pathological data.
Conclusion: Our results demonstrate that MRI, with both endorectal and pelvic phased array coils together or with pelvic phased array alone, offers high-resolution images of the entire mesorectum and allows for an accurate staging of rectal cancer. Visualization of the different layers of the rectal wall is improved with the use of the endorectal and pelvic phased array coils together, compared with the pelvic phased array coil alone. Thus we can conclude that MRI is of high value in establishing the best treatment strategy for rectum cancer patients.
E174. MR Imaging of Fistula in Ano
Knechtges P. M.; Willatt J. M.; Weadock W. University of Michigan Health Systems, Ann Arbor, MI
Address correspondence to P. Knechtges (knechtge{at}med.umich.edu)
Background: Fistula in ano is an abnormal communication between the anal canal and the perianal skin. Perianal abscess and fistula in ano are thought to be the acute and chronic manifestations of the same disease process. Fistula in ano arises either from a cryptoglandular process, or from an inflammatory process such as Crohn's disease. The cryptoglandular hypothesis states that infection begins in the perianal glands and crypts and extends into the muscular wall of the anal sphincters to cause an anorectal abscess. This anorectal abscess either drains spontaneously or is treated surgically. Occasionally, a granulation tissue lined tract is left behind forming a fistula in ano. This fistula in ano causes recurrent symptoms. Treatment of fistula-in-ano is typically surgical. Some fistulas recur despite surgical intervention. Recurrence is typically due to infection. Advances in imaging, in particular with MRI, have been shown to characterize fistulas and the associated abscesses and tracts more accurately than examination under anesthesia. Information from preoperative MRI can be used to determine the surgical approach and reduce postoperative recurrence, especially in complicated cases.
Key Issues: MRI provides excellent contrast resolution enabling the reader to see the anatomy not only of the anal canal, but also of active and fibrotic fistulous tracts. An understanding of anal canal anatomy is essential for the evaluation and the subsequent classification of anal fistulae. An appropriate MR imaging technique, i.e. choice of imaging coils, MR sequences, and imaging planes, is also critical for the imaging of fistulae in ano.
Format: 1. An interactive tutorial on the anatomy of the anal canal on MRI followed by an interactive quiz on the anatomy in different imaging planes. 2. An interactive tutorial on the classification of fistula in ano followed by an interactive quiz. 3. A tutorial on the optimization of MRI technique followed by an interactive quiz.
Teaching Points: 1. The importance of preoperative imaging to reduce postoperative recurrence of fistula in ano. 2. The normal MRI anatomy of the anal canal. 3. The classification of fistula in ano for operative planning. 4. Optimization of MRI technique for evaluation of fistula in ano.
E175. Gallbladder Pathology Demonstrated by MDCT— A Pictorial Review
Eschbach K. A.; Siegel S. Maine Medical Center, Portland, ME
Address correspondence to K. Eschbach (eschbk{at}mmc.org)
Background: Traditionally, gallbladder pathology has been under diagnosed on CT. The increasing availability of multidetector row CT (MDCT) has led to an enhanced role for CT in imaging of the biliary system. Until now, ultrasound, nuclear medicine scintigraphy, endoscopic retrograde cholangiopancreatography (ERCP), oral cholecystography and Magnetic Resonance Cholangiopancreatography (MRCP) have all been used to evaluate for gallbladder pathology. The purpose of this exhibit is to present the CT features of a wide variety of pathologically proven gallbladder pathology.
Key Issues: This program is rich in images and diverse in content. Topics include, but are not limited to entities such as acute cholecystitis and its complications, the various presentations of adenomyomatosis, gallstone ileus, choledocholithiasis, porcelain gallbladder, gallbladder changes secondary to hepatitis, gallbladder carcinoma, cholangiocarcinoma and metastatic disease to the gallbladder. Each case shown will be accompanied by a detailed description of imaging findings. Awareness of the manifestations of gallbladder disease on MDCT will assist in a confident diagnosis.
Format: This didactic exhibit will be shown in a case presentation format. Annotated MDCT images will display a broad range of gallbladder pathology previously diagnosed by other modalities.
Teaching Points: Teaching points of this exhibit include; 1) Increased reader familiarity with the MDCT features of a wide spectrum of gallbladder pathology. 2) Increased ability to detect gallbladder pathology on CT will lead to increased sensitivity of detection. 3) Increased detection will lead to improved patient care.
E176. Current Imaging Approach to Biliary Malignancies
Anderson S. W.; Rho E.; Soto J. Boston University Medical Center, Boston, MA
Address correspondence to S. Anderson (stephan.anderson{at}bmc.org)
Background: With the implementation of 64MDCT technology and its increasing use in various clinical applications, biliary pathologies are often initially visualized by CT. As 64MDCT affords the ability to generate isotropic datasets, these techniques offer an unprecedented ability to identify and characterize biliary pathology. Specifically, 64MDCT offers a powerful diagnostic tool in the evaluation of biliary malignancies. In light of these advances, the role of MRI is evolving but MRI remains an exquisitely powerful tool in fully characterizing and staging biliary malignancies.
Key Issues: This exhibit will highlight imaging features of biliary malignancies using both 64MDCT and MRI techniques. The current use of 64 MDCT technology and its application to biliary imaging will be discussed. This includes protocol issues specific to biliary imaging. Additionally, advanced postprocessing techniques such as multiplanar reformations and minimum intensity projections, techniques particularly suited to the evaluation of biliary pathology, are detailed. This exhibit will discuss the current applications of MRI to the evaluation of biliary pathology, particularly biliary malignancies. The current use of MRCP in characterizing biliary malignancies is discussed.
Format: This exhibit will be a didactic presentation organized into discussion and illustration of issues specific to biliary malignancies. This is followed by discussion and illustration of issues specific to 64MDCT and MRI in their approach to biliary pathology, specifically biliary malignancy.
Teaching Points: 1. Issues specific to biliary malignancies are detailed including description of staging. 2. 64MDCT technology affords the ability to identify and characterize biliary malignancy. 3. Postprocessing techniques such as MPR and MinIP applications are crucial in biliary imaging. 4. MRI retains a crucial role in the noninvasive evaluation of biliary malignancy.
E177. Imaging of Fatty Hepatic Masses and Processes
Shah K.; Myers D. T. Henry Ford Hospital, Detroit, MI
Address correspondence to K. Shah (kshah_md{at}hotmail.com)
Background: Identifying the presence of macroscopic fat or intracellular lipid within a hepatic mass provides a key diagnostic clue. Although the differential diagnosis of hepatic lesions is broad, the presence of fat is a feature that allows the radiologist to narrow this list particularly when combined with other imaging features. Multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI) both provide techniques for the detection of macroscopic and intracellular fat. With multiple illustrated examples, this exhibit will demonstrate modality specific techniques and the salient imaging features that aid the radiologist in arriving at specific diagnoses for fat containing hepatic masses and processes.
Key Issues: Low density lesions on CT, in the range of -40 to -100 Hounsfield units, allow for relative easy detection of macroscopic fat. However, either due to small size of fat components or the fact that the lipid is predominantly intracellular, CT may not demonstrate convincing evidence to indicate the presence of fat. MR imaging can confirm the presence of fat with chemical shift imaging with in-phase and out-of-phase gradient echo sequences and fat suppression techniques. During in-phase imaging, water and lipid signals are additive. During out of phase imaging, the appropriate selection of echo time allows for differing relative contributions of fat and water signal allowing one to detect a drop in signal intensity in tissues containing intracellular fat. Fat suppression techniques may be more useful in the detection of macroscopic fat. We will demonstrate with numerous examples the heterogeneous group of fatty neoplasms and disease processes including, but not limited to, hepatocellular carcinoma, hepatic adenoma, focal nodular hyperplasia, hepatic angiomyolipomas, hepatic lipomas, and focal and geographic fatty change. Through these examples, the CT criteria and MRI techniques utilized including opposed phase imaging and selective fat suppression will be explained.
Format: We will utilize a didactic based approach with numerous CT and MR case illustrations to describe CT criteria and MRI technique for detecting fat containing lesions. These examples will highlight the features that allow radiologists to arrive at an accurate diagnosis.
Teaching Points: 1) Imaging techniques for fatty neoplasms and disease processes of the liver. 2) Salient imaging findings in CT and MR to characterize fat containing hepatic neoplasms. 3) Pattern of findings in steatosis of the liver.
E178. Evaluation of Cirrhosis and Chronic Hepatitis with Diffusion Weighted MRI
Fan X. C.1; Hussain H. K.1; Adusumilli S.1; Marrero J. A.2; Chenevert T. L.1 1. University of Michigan Department of Radiology, Ann Arbor, MI; 2. University of Michigan Internal Medicine Department, Ann Arbor, MI
Address correspondence to X. Fan (xfan{at}umich.edu)
Objective: Liver histology is considered the gold standard for establishing the severity of hepatic fibrosis. Currently, there is no imaging test that allows reliable detection of early cirrhosis. Diffusion weighted MRI and measurement of the apparent diffusion coefficient (ADC) allows quantification of microscopic molecular motion of water and may be useful in the evaluation of liver fibrosis. We obtained liver ADC measurements in patients with cirrhosis, chronic hepatitis, and normal livers, with the goal of utilization of the ADC measurements to differentiate cirrhosis from chronic hepatitis, and ultimately staging hepatic fibrosis.
Materials and Methods: 91 patients were imaged on a GE 1.5-T Excite spectrometer using a torso-phased-array coil. Following the acquisition of our routine precontrast sequences, diffusion-weighted imaging (DWI) was performed during suspended respiration using single shot echoplanar imaging with isotropic diffusion weighting (TR/TE 6,000/62.5 msec, 40 x 40 cm FOV, 128 x 128 matrix size, 10mm slice thickness, b values of 0 and 500 s/mm2, 24 sec breath-hold). ADC maps were generated using vendor-provided software (FuncTool 2, GEMS). Cirrhosis was determined by histology and clinical/imaging features. Chronic hepatitis was determined by viral titer, liver function test and/or liver biopsy.
Results: A total of 91 patients were imaged (56 with cirrhosis, 12 with chronic hepatitis, and 23 with normal liver). The mean ADC and standard deviation for patients with cirrhosis was (1.15 ± 0.12) x 10-3 mm2/s, for patients with chronic hepatitis was (1.26 ± 0.14) x 10-3 mm2/s, and for normal liver was (1.47 ± 0.16) x 10-3 mm2/s. The liver ADC values were lower in patients with cirrhosis compared with chronic hepatitis (p = 0.032), and significantly lower than normal livers (p = 4.6 x 10-10). Liver ADC values in patients with chronic hepatitis without cirrhosis were higher than in cirrhosis but lower than in normal livers (p = 0.0005).
Conclusion: Our data show that the ADC value of the cirrhotic liver is lower than that of chronic hepatitis, and both are significantly lower than that of the normal liver. Although there is some overlap, the ADC value difference between cirrhosis and chronic hepatitis is statistically significant (p < 0.05), indicating that diffusion weighted MRI and evaluation of ADC value may have a role to play in differentiating cirrhosis from chronic hepatitis.
E179. The Preoperative Liver: A Pictorial Review of a Spectrum of Findings On Computed Tomography of the Abdomen Following Portal Vein Embolization
Gonzalez-De Luna M. A.; Madoff D. C.; Szklaruk J. MD Anderson Cancer Center, Houston, TX
Address correspondence to M. Gonzalez-De Luna (moongonzo{at}yahoo.com)
Background: At least 20% volume of a liver remnant is required to minimize postoperative morbidity and in some cases mortality following hepatic resection (40% in cirrhotic livers). Portal vein embolization (PVE) was developed as a means to induce hypertrophy of the nonresected liver remnant. The introduction of PVE has permitted the inclusion of patients who otherwise may not be considered surgical candidates due to high morbidity of surgical resection. As this procedure becomes more common, familiarity with the spectrum of findings in the preoperative computed tomographic (CT) abdominal examination is essential. The purpose of this study is to present the spectrum of findings in the preoperative CT evaluation of the abdomen following PVE.
Key Issues: The CT examination of the abdomen with and without administration of contrast of patients who have undergone PVE will be presented. The images will include examples of a spectrum of imaging findings in the preoperative CT examination following the PVE procedure. Among the examples to be demonstrated include: hypertrophy of the liver remnant, atrophy of the embolized segments, periportal adenopathy, perfusion abnormalities, portal vein thrombus, subcapsular hematoma, misplaced coils, portal hypertension and infarction.
Format: This interactive exhibit will review the clinical background and present examples of the imaging features in the preoperative liver in patients who have undergone PVE. The attendant will select from a master menu among the following two topics: (a) PVE - clinical background, (b) List of imaging findings. Upon selection of topic (a) a brief presentation on the technique and applications of PVE will be presented. Upon selection of topic (b) a second menu will list the various findings that may be encountered in the CT of the abdomen exam following PVE. The attendant will then click on the finding and a hyperlink will demonstrate the finding seen on the CT examination. A brief explanation of the pathophysiology and clinical significance of the findings will also be presented.
Teaching Points: The attendant will be able to identify imaging features found on the CT abdomen evaluation following portal vein embolization. The attendant will learn the clinical implications and pathophysiology of imaging findings following PVE. The attendant will be familiar with the indications, technique, and applications of PVE.
E180. Various Focal Hepatic Lesions with Delayed Contrast Enhancement on CT and MR Imaging
Lee Y.; Oh S.; Jung S.; Jung G.; Rha S.; Byun J.; Lee J. Kangnam St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea
Address correspondence to Y. Lee (yjleerad{at}catholic.ac.kr)
Background: Dynamic pattern of contrast enhancement is very important for differential diagnosis of focal hepatic lesions. When a focal hepatic lesion shows early arterial enhancement and delayed washout, it is not difficult to diagnose hepatocellular carcinoma. However, delayed contrast enhancement with/without arterial enhancement may lead to diagnostic dilemma, since a wide variety of tumorous or nontumorous conditions can be included in differential diagnosis; hemangioma, cholangiocarcinoma, metastatic tumors, sclerosing hepatocellular carcinoma, hepatocholangiocarcinoma, inflammatory pseudotumor, hepatic abscess and epithelioid hemangioendothelioma.
Key Issues: We will illustrate imaging findings of dynamic CT or MR of the liver.
Format: We will use a didactic format structured by pathology.
Teaching Points: Knowledge of various focal hepatic lesion with delayed contrast enhancement allows appropriate differential diagnosis of focal hepatic lesions.
E181. Atypical Hemangiomas with Minimal Peripheral Enhancement among Small Hepatic Hemangiomas on Multidetector-row CT: Incidence and Clinical Significance
Choi J.; Ahn K.; Hwang K.; Lee J.; Lee C.; Park C. Korea University Guro Hospital, Seoul, South Korea
Address correspondence to J. Choi (mutzin{at}empal.com)
Objective: Small minimally-enhancing hypodense nodules are not infrequently encountered in daily practice after introduction of multidetector-row CT (MDCT) due to its high resolution. The diagnostic dilemma arises especially when patients have underlying malignancy. Is this a benign nodule or a metastatic nodule? To our experience many of these nodules are small minimally-enhancing hepatic hemangiomas. These atypical hemangiomas have been known to be very infrequent. The purpose of the study is to assess the incidence of hepatic hemangiomas with minimal peripheral enhancement among small hemangiomas on MDCT and to find the CT features to help make differential diagnosis.
Materials and Methods: Images of 123 hepatic hemangiomas in 90 patients were retrospectively reviewed. All hemangiomas were diagnosed on 16-channel MDCT or MRI according to the pathognomonic imaging findings or no interval change on follow-up imaging over 6 months or longer. Of 123 hemangiomas, 90 small hemangiomas less than 2.0 cm in 67 patients were included in this study. The mean size of small hemangiomas was 1.3 cm (range: 0.5–2.0 cm). Small hemangiomas were classified into 3 groups according to the enhancement patterns: (1) homogeneous enhancement during the arterial and delayed phases (homogeneous enhancement), (2) arterial peripheral globular enhancement with gradual fill-in (centripetal enhancement), and (3) minimal peripheral enhancement with persistent central hypovascularity during the arterial and delayed phases (minimal peripheral enhancement).
Results: Among 90 small hemangiomas, 11 hemangiomas showed homogeneous enhancement; 58 hemangiomas showed centripetal enhancement; 21 hemangiomas showed minimal peripheral enhancement. The incidence of hemangiomas with minimal peripheral enhancement was 23.3%, higher than that of homogeneously enhancing small hemangiomas, 12.2%. Although most part of hemangiomas with minimal peripheral enhancement remains hypodense on the delayed images, they revealed a tiny peripheral globular enhancing portion.
Conclusion: Hemangiomas with minimal peripheral enhancement are not infrequently encountered among small hepatic hemangiomas on MDCT. Tiny delayed enhancing portion at the periphery of a small hypodense nodule can be a differential diagnosis point of hemangiomas with minimal peripheral enhancement from other tumors. Awareness of relatively high incidence and CT feature of hemangiomas with minimal peripheral enhancement may be helpful in differential diagnosis for minimally enhancing small hepatic nodules.
E183. Two Case Reports of Anomalous Hepatic Venous Drainage with a Review of the Normal Development of the Hepatic Venous System
Nguyen R.; Zollinger L.; Akram S.; Corey D.; University of Utah, Salt Lake City, UT
Address correspondence to R. Nguyen (richard.nguyen{at}hsc.utah.edu)
Background: We present two cases of anomalous hepatic venous drainage which were both subclinical. These anomalous hepatic drainage systems have been discussed in the literature and with increasing hepatic surgeries and transjugular intrahepatic portosystemic shunts, the prior knowledge of these variants likely would impact treatment and interventional planning. With current multidetector CT cross-sectional imaging as well as with MRI, these anatomic variations can be accurately depicted.
Key Issues: We will discuss the normal development of the hepatic venous system and compare this to the two case reports of variant anatomy. Imaging findings from the two case reports are from multidetector contrast-enhanced CT scans with multiplanar reformations.
Format: The format of our exhibit will be didactic with an introduction of the two case reports at our institution. This will be followed by a discussion of the imaging findings. Finally, a review of the literature will be discussed with graphical demonstration of the normal hepatic venous development and comparison with the case reports we present.
Teaching Points: We hope to provide a comprehensive review of the normal hepatic venous development and discuss imaging options to better serve referring services in patients that may undergo surgical or other interventional procedures with these anatomic variants.
E184. The MRI Appearance of Hepatic Lesions Following Radiofrequency Ablation
Kowal D. J.; Wable S. Albert Einstein Medical Center, Philadelphia, PA
Address correspondence to D. Kowal (kowald{at}einstein.edu)
Background: Radiofrequency ablation (RFA) has become an increasingly utilized treatment for unresectable hepatic tumors. Many radiologists who are not routinely exposed to this procedure are often unaware of the typical postprocedure MRI appearance of ablated lesions.
Key Issues: A small series of MRI examinations of the liver in patient's status-post RFA were reviewed, and characteristic findings of ablated hepatic lesions were identified. The imaging time after ablation ranged from approximately 2 weeks to 3 years. On T1-weighted images, the ablated lesions are isointense to hyperintense. A hypointense rim is often present. Older lesions tend to demonstrate a more uniform hyperintensity on T1-weighted images. On T2-weighted images, the lesions are usually hypointense with a hyperintense rim. This hyperintense rim may represent edema, and it can persist for 4-12 months after ablation. A T2-hypointense rim was present in a single lesion approximately 3 years after ablation, which suggests development of a fibrous capsule. On the post-gadolinium images, there is often faint peripheral enhancement on the immediate and 1-minute images. However, peripheral enhancement is not always present, and this finding is therefore not a time sensitive feature. The degree of rim enhancement may also depend upon both the extent of liver disease in the host, and the extent of ablation. Also, the presence of the T2-hyperintense rim is not always associated with peripheral enhancement. Successfully ablated lesions are completely devoid of internal enhancement. Smaller RFA lesions tend to become less apparent on subsequent examinations, whereas larger lesions tend to persist. Finally, it is increasingly common to visualize the RFA tract, which will demonstrate signal characteristics similar to the ablated lesion.
Format: This educational exhibit will be organized with a didactic approach, with images highlighting the aforementioned imaging characteristics of RFA lesions. Information detailing the time interval between ablation and MR imaging will be provided.
Teaching Points: A lesion with a surrounding rim demonstrating T1-hypointensity and T2-hyperintensity, when present, is a strong indicator of a previous RFA, but this appearance cannot accurately determine the age of the ablation. However, peripheral T2-hyperintensity suggests a more recent RFA, as it likely represents edema or edema and reactive changes. Gadolinium enhancement within the lesion remains the most reliable predictor of residual viable tumor.
E185. Computed Tomography Evaluation of Auxiliary Partial Orthotopic Liver Transplantation in the Pediatric Population.
Bloomer C. W.; Kato T.; Casillas J. Jackson Memorial Hospital/University of Miami, Miami, FL
Address correspondence to C. Bloomer (cbloomer{at}um-jmh.org)
Background: Auxiliary partial orthotopic liver transplantation (APOLT), a new procedure in this country, was created as a temporary measure in the setting of fulminant hepatic failure and noncirrhotic metabolic liver disease: this procedure replaces enzymes and liver function without complete removal of the native liver. Typically a left hepatic lobectomy is performed and the donor left lobe is orthotopically placed. Theoretically, when the acute liver failure has resolved, weaning of the immunotherapy would allow the patient's native liver to slowly resume its productivity while the transplanted liver lobe slowly involutes. In the pediatric population this is particularly imperative as the side effects of immunosuppression can be significant and quality of life detrimentally affected. A unique series of pediatric APOLTs is presented here, with serial CT image findings and clinical and pathologic correlation.
Key Issues: An internal review of computed tomography (CT) studies was performed. Pediatric cases, aging from 14 months to 9 years of age (1 female), 6 months to 10 years posttransplantation were imaged as part of their routine care posttransplantation. A review of CTs from the peri-posttransplantation period and up to 10 years posttransplantation is presented. Liver function tests (LFTs) were reviewed. Comparison of LFTs, CT and outcome is discussed.
Format: Didactic: The exhibit will be a case review with retrospective analysis of imaging findings and outcomes.
Teaching Points: A full discussion on APOLT: indication, technique and outcomes will be discussed along with management of the pediatric APOLT patient. Imaging indications, characteristics and predictive features will be discussed. Discussion on how to recognize and describe these interesting findings is presented. Correlation with LFTs and CT findings will be presented. Knowledge of the surgical technique of auxiliary partial orthotopic liver transplantation (APOLT) and awareness of the normal CT appearance permit early detection of complications and may prevent misdiagnosis.
E186. Radiological and Clinical Findings of Vascular Complications Following Living Donor Liver Transplantation: Review and Update in Knowledge with Experience of 728 Cases
Kim K.; Lee S.; Kwon H.; Kim S.; Lee S.; Lee M. Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
Address correspondence to K. Kim (kimkw{at}amc.seoul.kr)
Background: Although basically the same, there are some differences between orthotopic liver transplantation from cadaveric donor (OLT) and living donor liver transplantation (LDLT), regarding the surgical procedures and the prevalence of vascular complications. Therefore, it is important for a radiologist to be updated about various radiological and clinical findings in patients with vascular complications following LDLT.
Key Issues: 1. Surgical procedures and type of vascular complications of LDLT. 2. Radiological and clinical findings of vascular complications following LDLT a. Hepatic artery: stenosis/thrombosis, dissection, pseudoaneurysm, arteriovenous fistula, arterial steal syndrome, reconstitution after subclinical stenosis. b. Portal vein: stenosis/thrombosis, bidirectional or reversed portal flow, persistent portal hypertension. c. Hepatic vein: stenosis/thrombosis, pre- and postanastomotic outflow obstruction.
Format: Didactic, organized by disease category.
Teaching Points: 1. To discuss the differences between OLT and LDLT, regarding the surgical procedures and the type of vascular complications. 2. To review and update in knowledge about radiological and clinical findings of vascular complications following LDLT.
E187. Ultrasound Imaging of Posttransplant Liver Complications with Multimodality Correlation
Baccei S.; Han R.; Doherty F. Tufts - New England Medical Center, Boston, MA
Address correspondence to S. Baccei (sbaccei{at}tufts-nemc.org)
Background: Imaging plays an essential role both in detecting and characterizing post liver transplant complications but also serves to provide appropriate therapeutic guidance related to the medical and surgical interventions that follow. Our institution has performed nearly 700 orthotopic liver transplantations between January 1, 1988 and July 31, 2006 to compliment the roughly 79,000 performed within the United States between the same time period. As transplantation becomes an increasingly common treatment for both severe acute liver failure and end stage chronic liver disease immediate postop evaluation and subsequent follow-up relies heavily on ultrasound for a fast, safe, and relatively inexpensive yet powerful diagnostic tool.
Key Issues: Nearly half of both symptomatic and asymptomatic post liver transplant complications are unrelated to rejection. Consequently, because ultrasound is relatively inexpensive, readily accessible, and lacks ionizing radiation, it is often the first modality utilized for detecting abnormalities other than rejection. We include primary ultrasound images with multimodality correlation illustrating arterial and venous stenosis of the transplant and recipient vasculature; pseudoaneurysm; acute/subacute arterial and venous thrombosis; postoperative transplant edema; bileoma; pneumobilia; postop hepatitis and liver abscess; Budd-Chiari Syndrome; fluid collections; and hematomas.
Format: This exhibit employs high quality, original ultrasound images in a didactic manner to illustrate the various complications and pathologies listed above. Multimodality correlation with current literature review describing the abnormality further supports each topic. A description of the pathology presented in each image with commentary relating to image acquisition, impact on patient management, and ultimate outcome are included.
Teaching Points: The purpose of this exhibit is to provide an image based demonstration of the complications following orthotopic liver transplantation using original high quality ultrasound images with multimodality correlation. A thorough understanding of the ultrasound appearance and early recognition of these abnormalities narrows the diagnostic possibilities and guides the subsequent imaging and therapy. The various cases presented in this exhibit will reinforce the appearance and significance of post liver transplant complications.
E188. Ultrasound in the Diagnosis and Follow-up of Hepatic Artery Thrombosis after Liver Transplantation in Adults: Early Versus Late Thrombosis
Horrow M. M.; Chaudhri Y.; Reich D.; Manzarbeitia C. Albert Einstein Medical Center, Philadelphia, PA
Address correspondence to M. Horrow (horrowm{at}einstein.edu)
Background: Hepatic artery thrombosis (HAT) after liver transplantation is an uncommon, but potentially devastating complication. Immediate HAT within one week of transplantation is typically treated with surgical revascularization and may result in significant hepatic necrosis. Delayed HAT may have a more indolent course, often with biliary abnormalities because the bile ducts derive their blood supply from the hepatic artery. Doppler ultrasound is the screening modality of choice for HAT with confirmation by angiography, CTA or MRA. Doppler and gray scale ultrasound may show significantly different findings in immediate and late HAT.
Key Issues: This exhibit will demonstrate cases of immediate and late HAT with Doppler and gray scale ultrasound, using angiography, CT, and cholangiography as complementary procedures. In our hands, Doppler ultrasound is 100% sensitive for HAT in the immediate period, but decreases in sensitivity in the late period because of interval development of collaterals. Examples of true positive and false negative Doppler studies will be demonstrated with a discussion of how subtle changes in appearance of the waveforms can still indicate HAT. The gray-scale findings of hepatic necrosis, and biliary abnormalities with biliary dilatation, sludge, strictures, bilomas and abscess will be demonstrated, with correlative imaging. We will highlight the findings in a cohort of our patients who are long term survivors with HAT.
Format: This is a didactic exhibit, demonstrating: 1. The components of a normal post transplant Doppler exam, 2. Examples of Doppler and gray scale imaging of immediate HAT with angiographic and CT correlation, 3. Examples of late HAT with true positive and false negative studies with correlative imaging. Biliary complications include biloma and abscess and cases will highlight the often subtle findings of biliary dilatation and sludge on ultrasound as well as slight changes in hepatic artery waveforms as the only sign of HAT.
Teaching Points: 1. Doppler ultrasound is extremely sensitive for HAT in the immediate period based upon lack of arterial flow. 2. Ultrasound becomes less sensitive for HAT as the interval between transplantation and ultrasound increases. 3. Arterial collaterals can develop in adults after HAT and are detectable by ultrasound 4. Biliary dilatation can be quite subtle on ultrasound because sludge may fill the ducts. 5. Biliary abnormalities should prompt further imaging for HAT even when ultrasound shows arterial flow to the liver.
E189. Various Complications in Living Liver Donors After Partial Liver Harvest: An Illustrative Radiologic Review
Kwon H.; Kim K.; Kim M.; Lee M.; Lee S. Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
Address correspondence to H. Kwon (hjkwon{at}amc.seoul.kr)
Background: Attributed to the shortage of cadaveric donors, living donor liver transplantation (LDLT) has been widely accepted as an alternative method for patients with end-stage liver disease. Especially in many Asian countries where cadaveric organ harvesting is limited, it has become the only realistic option to overcome the organ shortage and, therefore, has been rapidly implemented and expanded. However, despite the overwhelming benefit of LDLT for critically ill patients with end-stage liver disease, it should not undermine the concern for the safety of the healthy living donors. Although a paucity of data exists regarding the complications and relative safety of the procedure, several reports claim donors' deaths after living liver donation in the United States and Europe. Risks to the donor include those associated with invasive presurgical testing, surgical procedures, and postoperative care. Some complications may become fatal if the diagnosis and treatment are delayed. Thus, an early detection of postoperative complication is of utmost importance for a timely intervention, and meticulous clinical and radiological surveillance is mandatory for living liver donors in their postoperative period. CT usually plays a key role in detection of serious postoperative complications.
Key Issues: In this exhibit, we present an illustrative overview of various types of partial liver harvesting in living liver donation along with usual postoperative findings on multidetector-row CT (MDCT) and discuss MDCT findings of various postoperative complications in living liver donors. We categorized the complications into (1) postoperative bleeding: 1) subcapsular hematoma associated with preoperative percutaneous biopsy, 2) adrenal hemorrhage, 3) massive peritoneal bleeding with dislodgement of hemoclip, 4) peritoneal or retroperitoneal hemorrhage; (2) biliary complication: 1) biloma from persistent bile leak, 2) bile duct stricture; (3) vascular complication: 1) hepatic vein thrombosis, 2) portal vein stenosis/thrombosis, 3) caudate lobe ischemia/infarction; (4) gastrointestinal complication: 1) adhesive band ileus, 2) gastric outlet or duodenal obstruction, 3) incisional hernia; (5) miscellaneous: deep vein thrombosis-pulmonary embolism.
Format: Didactic, by pathophysiology.
Teaching Points: To gain a perspective on the surgical procedures and normal postoperative MDCT findings in living liver donors. To review MDCT findings of various complications in living liver donors following right or left lobectomy.
E190. Infectious Diseases of Liver—CT and MR Imaging Patterns
Batra K.1; Chhabra A.1; Bhoot V.2; Mithaiwala R.2; Esposito F.2; Mohsen N.1 1. Drexel University College of Medicine, Philadelphia, PA; 2. Mercy Catholic Medical Center, Philadelphia, PA
Address correspondence to K. Batra (kirandnb{at}yahoo.com)
Background: The increasing number of susceptible hosts, immigrant population, hepatitis and HIV patients and use of interventional radiology related procedures have likely contributed to a variety of infectious conditions of liver. With frequent use of abdominal CT and MRI for evaluation of liver lesions, we have encountered a number of these lesions and an attempt has been made to distinguish them based on their imaging appearances and available clinical information.
Key Issues: 1. Review of the use of CT and MR imaging in the evaluation of common and uncommon liver infections. 2. Demonstration of key imaging features of various liver infections such as, viral hepatitis, hematogeneous and biliary pyogenic, tubercular, fungal, echinococcal and amebic abscesses with relevant case examples.
Format: The exhibit will be in a quiz format with summary map for approach to liver infections in the last couple of slides.
Teaching Points: 1. Learn to differentiate appearances of liver infections from tumors on the basis of imaging findings and the available clinical information. 2. Learn the aunt minnie CT and MRI patterns of various common and uncommon infectious diseases of liver. 3. Formulate an approach to come to a reasonable differential and even definitive diagnosis in some cases.
E191. Infection in the Liver: Typical and Atypical Imaging Manifestations
Volpacchio M. M.; Maury M.; Cura A.; Baltazar A. Hospital de Clinicas Jose de San Martin, Buenos Aires, Argentina
Address correspondence to M. Volpacchio (mvolpacchio{at}gmail.com)
Background: The liver is a common site of infectious processes both as the primary focus and also as a target of systemic infections. Clinical manifestations and laboratory findings are often nonspecific. Therefore, imaging evaluation has a prominent role to establish the presence of an infection process as well as the site and extent of involvement. On occasion, it also allows the establishment of a confident etiologic diagnosis. Different diagnostic modalities also help to guide various diagnostic and therapeutic procedures. In this educational exhibit we intend to illustrate typical and atypical imaging manifestations of various focal and diffuse infections in the liver including bacterial, viral, mycotic y parasitic etiologies as well as its complications, with emphasis on clues which may assist in suggesting a specific diagnosis when possible.
Key Issues: This exhibit will describe common and uncommon infectious diseases of diverse etiologies and their typical and atypical manifestations on imaging studies. References to the pathophysiology and morphologic basis of the findings will be included. All classic imaging modalities will be shown with an emphasis on CT.
Format: The format is didactic. We will use a format similar to a pictorial essay. It will be structured by pathology as well as etiologic agent.
Teaching Points: The viewer will have the opportunity to see the various imaging manifestations of infectious process in the liver, its complications and differential diagnosis in an educational format which will show typical as well as atypical findings.
E192. Mesenteric Masses and Their Differentiating Characteristics
Jati A.2; Ji H.1; Ramaiya N.1 1. Dana Farber Cancer Institute, Boston, MA; 2. VA Medical Center, West Roxbury, MA
Address correspondence to A. Jati (anupmajati{at}yahoo.com)
Background: Mesentery is a peritoneal reflection which consists of two fused layers and creates a potential subperitoneal space for the spread of pathology. It may be involved by inflammatory, infectious or neoplastic conditions as well as congenital anomalies. Mesenteric lesions can be cystic or solid. Mesentery is commonly involved by metastatic process; primary tumors of mesentery are less common. Congenital lesions of the mesentery are rare but it is important to differentiate them from other mesenteric tumors since it may play a vital role in management. Also it is difficult to biopsy the mesenteric masses as they may lie deep to the vital structures.
Key Issues: In this exhibit we present various case examples to illustrate the imaging findings and differential points between various mesenteric lesions like lymphangioma, enteric duplication cyst, enteric cyst, mesothelial cyst, pseudocyst, mesenteric teratoma, mesothelioma, pseudomyxoma, tuberculosis, fibrosing mesenteritis, fibromatosis, carcinoids, metastases, lymphoma, etc. We will also show correlation with other imaging modalities such as PET, if available.
Format: Didactic
Teaching Points: 1. Demonstrate CT pattern of mesenteric lesions. 2. Characterize major differential by solid and cystic mesenteric lesions. 3. Identify main radiologic features of various congenital, benign and malignant mesenteric lesions.
E193. Primary Mesenteric Neoplasms: CT, MR and Angiographic Appearances
Okada M.3; Iida E.3; Nakashima Y.3; Matsunaga N.3; Takano K.1; Miura G.2 1. Iwakuni Medical Center, Iwakuni, Japan; 2. Onoda City Hospital, Sanyo-Onoda, Japan; 3. Yamaguchi University School of Medicine, Ube, Japan
Address correspondence to M. Okada (radokada{at}yamaguchi-u.ac.jp)
Background: Primary neoplasms arising from the mesentery are extremely rare and are usually of mesenchymal origin. The majority of these tumors are histologically benign. However, the mesentery is one of the major avenues for the dissemination or lymphatic spread of tumor of abdominal and retroperitoneal cavity and the majority of the mesenteric tumors are usually these secondary tumors. Primary mesenteric neoplasms are divided into two groups; cystic and solid lesions. Cystic mesenteric neoplasms include cystic lymphangioma, mesenteric cyst, cyst adenoma (adenocarcinoma), cystic mesothelioma, and generally occur in children and young adults. Solid mesenteric neoplasms include hematogenous neoplasms (lymphoma, plasmacytoma), stromal cell tumors (gastrointestinal stromal tumor, neurofibroma), desmoid tumor, lipoma or liposarcoma. Patients with mesenteric neoplasms usually present with nonspecific symptoms of abdominal pain, weight loss, a palpable mass, or diarrhea. Hematoma and inflammation of the small or large bowel, including mesenteritis or diverticulitis, are also recognized as mesenteric masses and gynecologic tumor, such as a solid ovarian tumor, is sometimes difficult to be distinguished from a mesenteric tumor.
Key Issues: CT is a valuable method for displaying mesenteric tumors and useful for preoperatively assessing the relationship of the mesenteric masses to major abdominal vessels. Magnetic resonance (MR) imaging has the good resolution of tissue characterization and can identify a wider array of specific tissues. Lipid, fluid, hemorrhage, smooth muscle, fibrosis, solid malignant tissue, and hydrated soft tissue (including edema and mucin) have typical MR imaging properties. Consideration of the tissue composition of various pathologic processes in the mesenteric masses can narrow the differential diagnosis. Selective angiography is useful to detect the origin of the tumor.
Format: The characteristic findings of various mesenteric tumors depicted on CT, MRI and angiography are correlated with pathological finding.
Teaching Points: To know the various mesenteric tumors and these characteristic findings on CT, MRI and angiography. To discuss the important aspects of the differential diagnosis of primary mesenteric tumors from secondary mesenteric neoplasms, inflammatory pseudotumor or huge gynecologic tumor as well as potential pitfalls.
E194. Superior Mesenteric Artery Syndrome
Stafford K.; Miller R. I. University of Florida Shands Jacksonville, Jacksonville, FL
Address correspondence to K. Stafford (kscmd{at}msn.com)
Background: Superior mesenteric artery (SMA) syndrome is a rare but well recognized clinical entity occurring most often in women of asthenic body habitus. The syndrome is produced by compression of the third portion of the duodenum against the aorta by the SMA resulting in chronic, intermittent, or acute complete or partial duodenal obstruction. Normally, the SMA forms an angle of approximately 45° (range, 38–56°) with the abdominal aorta, and the third part of the duodenum crosses posterior and inferior to the origin of the SMA, between the SMA and aorta. If this angle is decreased for any reason it produces compression of the third part of the duodenum, resulting in SMA syndrome. The most common presenting age is 10–30 years and symptoms include epigastric pain, nausea, vomiting (bilious or partially digested food), postprandial pain, early satiety, or possibly subacute small-bowel obstruction. Relief of symptoms normally occurs when the patient is in the left lateral decubitus, prone, or knee-to-chest position while eating. Etiologies which decrease the angle of the SMA with the aorta include: thin body build, exaggerated lumbar lordosis, abdominal wall laxity, depletion of the mesenteric fat due to catabolic states such as cancer, surgery, burns, or psychiatric problems, or severe injuries, such as head trauma, leading to prolonged bed rest. Initial treatment is usually conservative and is geared toward adequate nutrition and proper post prandial positioning. Surgical measures such as duodenojejunostomy and laparoscopic surgery with lysis of the ligament of Treitz and mobilization of the duodenum have been used. Recognized diagnostic imaging includes upper GI series, CT scanning, MRA, and abdominal ultrasonography.
Key Issues: Small bowel follow through and upper GI studies show incomplete distention and filling defects, respectively, involving the third portion of the duodenum. Contrast fills this region with erect patient positioning. CT and MRA of the abdomen demonstrate dilatation of the proximal duodenum to the level of the SMA artery which produces extrinsic compression upon this portion of small bowel.
Format: Didactic format organized chiefly by the imaging findings in the various modalities used in this study including fluoroscopy, CT, and MRA.
Teaching Points: 1. Be able to recognize the signs and symptoms of SMA syndrome. 2. Understand which diagnostic tests can and should be used for diagnosis. 3. Be able to aid clinicians by recommending appropriate treatment options.
E195. Pancreatic Cancer Staging in the Era of Vein Reconstruction Surgery: What the Surgeon Wants to Know
Sandrasegaran K.; Patel A.; Rydberg J.; Tann M.; Maglinte
