Abstracts

defined by the presence of any LN !2 cm away from the celiac axis with classicsonographic features of size O1.0 cm, round, and hypoechoic with distinctmargins. Positive LN detection by PET-CT was defined by positive imaging by bothmodalities. Results: During the study period, 93 esophageal cancer patientsunderwent EUS; 34 also underwent dilation. 27 (79%) dilatations were successful.10/27 patients were excluded (no PET-CT). Of the remaining 17 patients, 12patients had both a negative EUS and PET-CT, 4 had a positive EUS and negativePET-CT, and 1 had a negative EUS and a positive PET-CT. In this cohort of patientswith both EUS and PET-CT, and the negative predictive value for PET-CT was only75%. Conclusion: PET-CT has a poor NPV and therefore a negative PET-CT does noteliminate the need for esophageal dilatation to assess celiac lymph nodes duringEUS for esophageal cancer staging. Larger prospective studies comparing EUS andPET-CT are needed to determine the true accuracy of both staging modalities.

M1460

Endoscopic Ultrasound (EUS) Identifies Ampullary Masses

Suitable for Endoscopic Ampullectomy (EA)Jason Conway, Sarba Kundu, John A. Evans, John Baillie, John H. Gilliam,Girish MishraBackground: EUS has become an important adjunct to ERCP for determining themost appropriate management of ampullary masses (endoscopic vs limited surgicalresection vs Whipple procedure). Aim: To determine the accuracy of EUS inidentifying ampullary lesions suitable for EA. Results: Majority of pts presented withjaundice (24%), abdominal pain (24%) or were asymptomatic (24%). Based on EUSstaging, resection was endoscopic (nZ6), localized surgical resection (nZ8) orextensive resection (Whipple procedure) (nZ13). Histopathology showed 13adenomas � high grade dysplasia(48%), 12 adenocarcinomas (adenoCA) (44%) and2 inflammatory ampullary tissue (8%). All adenoCAs were found in pts having theWhipple procedure. EUS was highly sensitive for staging T1 ampullary masses butperformed poorly distinguishing T2 from T3 lesions (Table 1). Conclusion: EUS ishighly accurate for identifying pts with T1 ampullary adenomas, avoiding the needfor aggressive surgery (Whipple procedure). Ampullary masses confined to themucosa and submucosa are suitable for endoscopic and localized surgicalampullectomy. Invasive adenoCAs should be treated with Whipple procedure: all inthis study were. Distinguishing T2 from T3 lesions was a challenge, however.

EUS performance (Table 1)

T Stage Sensitivity Specificity Kappa Accuracy

AB248 GAST

ROINTESTINAL E NDOSCOPY Vol ume 69, No.

T1

100% 40% 0.46 77.8% T2 0% 91.3% -0.11 77.8% T3 25% 95.7% 0.26 85.2%

M1461

Natural History of Intraductal Papillary Mucinous Neoplasms

(IPMNs) Based On Followed Contast-Enhanced EUS (CE-EUS)

Findings: Focusing On Malignant Alteration and Development of

Ductal Cancer of the PancreasEizaburo Ohno, Yoshiki Hirooka, Akihiro Itoh, Hiroki Kawashima,Toshifumi Kasugai, Takuya Ishikawa, Hiroshi Matsubara, Ryoji Miyahara,Yoshiaki Katano, Naoki Ohmiya, Yasumasa Niwa, Hidemi GotoBackground: Intraductal papillary mucinous neoplasms (IPMNs) of the pancreasvary from hyperplasia to invasive cancer pathologically, and the management ofIPMN has been controversial. We reported the usefulness of EUS for diagnosis ofmural nodules of IPMNs (‘‘Annals of Surgery’’ in-press). The purpose of thisretrospective study is to verify our diagnostic strategy and to elucidate the naturalcourse of long-term followed cases by evaluating serial changes of mural nodules inCE-EUS findings. Patients and Methods: Two hundred twenty-nine patients withIPMNs were examined by CE-EUS as the initial study since January, 2001. Ourindications for resection were as follows: the case of main-duct type, existence ofmural nodule with blood flow signal in CE-EUS (regardless of the nodule size) andcoexistence of ductal cancer cases. As to the follow-up cases (patient refusal ofoperation, mural nodule lacking color signals and under our operative indications,and so on.), EUS and/or CT was performed every 6 months. We retrospectivelyreviewed 148 cases followed over 6 months. We assessed carcinogenic rate ofIPMNs and investigated the relationship between the morphological changes ofmural nodules by CE-EUS and the histological changes. We defined carcinogenicrate as the summation of development of ductal carcinoma cases and malignantalteration cases of IPMN. Results: Median follow-up term was 25.4months (6-116months). Coexistence of ductal carcinoma developed in 2 of 143 (1.4%). Thosetwo cases were inoperable. Three-year and 5-year carcinogenic rate was,respectively, 8.7% and 18.3%. As to thirty patients (21%) resected in the follow-upperiod, the sizes of mural nodule on CE-EUS findings (confirmed by pathologicalfindings) in the cases of malignant IPMNs were significantly larger (4.51 � 0.69mm/

5 : 2009

yr vs 1.93 � 0.60mm/yr [pZ0.009]). Initial appearance of mural nodules wereobserved in 13cases. There were 10 with adenoma, 3 with carcinoma in situ andthere was no invasive carcinoma derived from IPMN. Conclusion: As to our follow-up study, carcinogenic rate of IPMNs was not infrequent. Enlargement oroccurrence of mural nodules may be a useful indicator to determine the timing ofsurgical treatment. Our diagnostic strategy was appropriate because there were noinvasive cases pathologically in newly occurrence cases. In conclusion, CE-EUS isa very useful diagnostic method for follow-up.

M1462

The Yield of Endoscopic Ultrasonography for Determining An

Etiology in Patients with Idiopathic Acute PancreatitisBrian R. Boulay, Stuart R. Gordon, Timothy B. GardnerAims: Although Endoscopic Ultrasound (EUS) is often used as part of theevaluation of idiopathic acute pancreatitis, the success of the technique atidentifying a disease etiology is unknown. We aimed to determine the rate at whichEUS evaluation changed the diagnosis or management of patients with acuteidiopathic pancreatitis. Methods: We retrospectively identified all patientssequentially referred to our medical center between March 1997 and July 2008 forEUS evaluation of acute or recurrent acute idiopathic pancreatitis. The etiology ofacute pancreatitis was not known at the time of each EUS examination, despite anextensive outpatient work-up including cross-sectional imaging. All EUS examswere performed by expert endosonographers. Patient charts were abstracted bytwo reviewers for baseline patient characteristics, previous evaluation ofpancreatitis, findings on EUS exam, and subsequent management. Results: Out of3375 sequential EUS exams performed at our medical center, 110 patientsunderwent EUS specifically for evaluation of acute or recurrent acute idiopathicpancreatitis. The mean patient age was 51 years (range 10-88) and 63% were female.71 (35%) patients had experienced multiple episodes of pancreatitis with a mean offour previous attacks. Nineteen patients (17%) had EUS findings which identifieda disease etiology or changed patient management. Of these, 11 patients hadfindings of choledocholithiasis or microlithiasis, indicating a biliary source ofpancreatitis. 3 patients (16%) had evidence of a dilated common bile duct withoutan intraluminal filling defect and underwent biliary sphincterotomy for presumedpapillary stenosis. Additional findings included cystic neoplasms of the pancreas intwo patients, islet cell tumor of the pancreas in one patient, inflammatory strictureof the pancreatic duct in one patient and one patient with pancreas divisum. 22patients (20%) were diagnosed with chronic pancreatitis based on EUS criteria,although no etiology was determined in this group. None of these patients hadbeen previously diagnosed with chronic pancreatitis. Conclusions: EUSexamination determined an etiology of disease in 17% of patients undergoingevaluation for acute or recurrent acute idiopathic pancreatitis. Given the oftensignificant challenges in identifying a cause of disease in this patient population,EUS does increase the diagnostic yield in some patients. All patients with recurrentpancreatitis should therefore undergo EUS evaluation before being labeled withidiopathic disease.

M1463

Risk of Malignancy in Patients with Isolated Dilation of Common

Bile Duct and Without CBD Stones On Abdominal ImagingAmith V. Reddy, Naveen B. Krishna, Jeremy A. Hartman, ChristopherD. Mehan, Banke AgarwalBackground: Isolated dilation of common bile duct (with normal sized pancreaticduct) is frequently noted on abdominal US/CT/MRI. Further diagnostic evaluationof these patients is often determined by the presence of abnormal LFTs andobstructive jaundice. We investigated the prevalence of malignancy in thesepatients and made comparison based on abnormal LFTs and jaundice. Patients andMethods: From our prospectively maintained database, we identified 86 patientswho underwent EUS for evaluation of dilated CBD (R7 mm) noted on US/CT/MRIscans. Patients with CBD stones or an identifiable mass lesion on imaging were notincluded. Obstructive jaundice was defined by presence of serum bilirubin O1.0mg/ml that was predominantly conjugated. LFTs were considered abnormal if therewere elevated alkaline phosphatase levels with or without increase in transaminaseslevels. The final diagnosis was based on surgical pathology or clinical follow up ofR12 months. Results: The mean age of 86 study patients (57 female) was 62.6 �13.9 years. 31 patients had jaundice (group A), 23 patients had abnormal LFTs(group B) and 32 patients had normal LFTs (group C). 54 patients had associatedabdominal pain and 14 patients had weight lossO10 lbs. The mean size of CBD andfinal diagnosis are summarized in figure 1. There were 4 patients with false negativediagnosis: in 2 patients no focal mass lesion was noted by EUS and in other twopatients a focal mass lesion was noted pressing on the common bile duct but thecytology failed to diagnose malignancy. EUS-FNA had 95.4% overall accuracy (87.1%in jaundice group), 63.6% sensitivity, 100% specificity, 100% PPV and 83.4% NPV fordiagnosing malignancy in this group. Conclusions: Among the patients with isolateddilation of CBD and without identifiable stones on US/CT/MRI, the risk ofmalignancy is significant only in patients with associated obstructive jaundice and isquite low even in patients with abnormal LFTs but without jaundice. EUS-FNA canbe helpful in further diagnostic work-up of these patients.

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