$1284 Diagnostic Accuracy of Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Cystic Lesions of the Pancreas Ishaan Kalha, Madhuhar Kaw, Sandeep Singh, Mihir Pad, Deborah Cohen, Jeffrey Morris. Peter Pisters, Jean-Nicolas Vauthey, Jeffrey Lee, Douglas Evans BACKGROUND: Endoscopic ultrasound and fine-needle aspiration (EUS-FNA) has gained wide acceptance as a modality for the diagnosis and staging of pancreatic cancer. EUS-FNA has also recemly been reported to differentiate benign from malignant cystic lesions of the pancreas. The aim of this study is to establish the accuracy of EUS-FNA in diagnosing cystic lesions when compared to surgical pathology. METHOD: We retrospecnvely analyzed all patients who underwent EUS-FNA of a cystic pancreatic lesion from 10/99 - 9/02. A positive FNA result was defined by the presence of adenocarcinoma or mucin; cytology reported as highly suspicious for adenocarcinoma was also considered positive. Cyst fluid CEA levels were defined as consistent with malignancy if greater than 500 units/ml. Cyst fluid amylase levels were defined as consistent with a benign inflammatory pseudocyst if greater than 5000 IU/L. RESULTS: EUS-FNA was performed on 84 patients with a mean age of 58.9 years. 63% were female patients. Fluid and mucnions material was successfully aspirated from the pancreatic cyst in 73 patients. 24 of the 73 patients underwent surgical resection of the pancreas. 15 of the 24 surgical patients were found to have adenocarcinoma or a mucinous neoplasm on final histopathology of the surgical specimen. 14 (93%) of the 15 patients were correctly diagnosed preoperatively by EUS-FNA. 9 of the 24 patients were found to have a nonmalignant diagnosis on final histopathology of the surgical specimen. 3 (30%) were correctly diagnosed either as serous cystadenomas (1) or inflammatory pseudo- cysts (2). 49 of 73 patients did not undergo surgery. EUS-FNA was positive in 21 of these patients; surgery was not performed because of medical co-mothidities, metastatic disease "or local tumor unresectability. Clinical follow-up supported advanced cancer in all 2t patients. EUS-FNA suggested benign disease in 28 of the 49 patients; clinical and radiographic follow-up has failed to demonstrate invasive cancer in any of these 28 patients. CONCLU- SION: EUS-FNA of pancreatic cystic lesions is an accurate technique for the differentiation of benign and malignant disease. It is the diagnostic procedure of choice in those patients who require a cytological diagnosis of malignancy to allow the delivery of chemotherapy or in patients with presumed benign disease (serous cystadenoma or pseudocyst) in whom observation is most appropriate. $1285 Endoscopically Inserted Endoluminai Receiver Coil for High-Resolution MRI of the Pancreas: Initial Results in an Animal Model Smgbert Faiss, Jonathan Lewin, Shenf Nour, Martin Zeitz, Jeffrey Duerk, Frank Wacker Background: In the last few years, magnetic resonance imaging (MRI) of the pancreas has assumed a special role in the diagnosis and staging of pancreatic diseases. The purpose of this study was to assess the feasibihty of high-resolution magnetic resonance imaging of the pancreas through application of an endnscopieally inserted endoluminal magnetic resonance receiver coil. This new diagnostic approach for MRI is comparable to the use of intraductal ultrasound which also yields a higher spatial resolution in comparison to conventional endoscopic ultrasound when used in the pancreatic duct. Method: A 0.032-inch internal magnetic resonance imaging receiver coil was endnscopically inserted into the pancreatic duct in four pigs using the biopsy channel of the duodenoseope in order to obtain high- resolution magnetic resonance images using T1- and T2 weighted sequences. Results: The pig anatomy prevented the usual transoral approach, however, transgastric access allowed the endoscopic transpapillary insertion of a receiver coil into the pancreatic duct in all animals without the need for sphincterotomy. The small swine pancreas could then be visuahzed by magnetic resonance imaging with a 0.3x0.3-mm in-plane resolution. Conclu- sion: High-resolution pancreas magnetic resonance imaging is feasible using an endoscopi- cally inserted endoluminal receiver coil. The smaller stomach and larger pancreatic duct diameter in humans will facilitate the procedure in its climcal application $1286 The Usefulness of 18FDG-PET scan in determination of treatment response in pancreatic cancer Seung Min Bang, Hye Won Chung, Seung Woo Park, Jae Bock Chung, Jin Kynng Kang, Mi Jni Yoon, Jong Doo Lee, Si Young Song Background: Concurrent chemoradiotherapy or chemotherapy is a mainstream of therapy for locally advanced unresectable pancreatic cacner. For the evaluation of treatment response, helical CT scan is considered as a standard method. However, consideringsevere desmoplastie reaction in pancreatic cancer and radiation effect of increased fibronogenesis, it may not be adequate to use CT scan for the treatment evaluation and also to detect the small metastatic lesion. Aims: We investigate the usefulness of 18FDG-PET for determining treatment response after concurrent chemoradiotherapy, and for detecting an early metastatic lesion. Methods and Materials: From Jan. 1999 to Oct. 2002, 14 patients of pancreatic adenocarcinoma, who underwent concurrent chemoradiotherapy and 1 patient received chemotherapy alone, were included for this study. 18FDG-PET scan was performed before and after the treatment. In all patients, abdominal CT scan and 18FDG-PET scan were performed simuhaneouly. The 18FDG-PET scan was analysed visually and semiqnantitatively using standard uptake value (SUV). Results: Among the 15 patients, only 3 cases (200%) were identical results with both follow-up CT and PET scan in determining the treatment response. With CT scan, the treatment responses were partial response@R) in 3 cases, stable disease(SD) in 8 cases, progressive dtsease(PD) in 4 cases. In contrary, with PET scan, PR in 6 cases: SD in 1 case, PD in 8 cases. All the clinical benefit responses such as pain and weight gain were matched with the results of PET. Furthermore. with follow-up PET scan, early liver metastasis were found in 2 cases and peritoneal seeding and distant lymph node metastasis in 2 cases. respectively, which were not detected with foUow-up dynamic CT scan. Conclusions: 18FDG- PET scan is very useful imaging method in determining the response evaluation after chemora- diotberapy and detecting the early metastasis. $1287 Usefulness of Contrast-Enhanced Coded Phase-lnversion Harmonic Ultrasonography for Differential Diagnosis of Pancreatic Diseases and Evaluation of Chemotherapy Masayuki Kitano, Yonichirou Suetomi, Kiyoshi Maekawa, Hiroka Sakamoto, Ryousuke Nakaoka, Toshihiko Kawasaki, Masatoshi Kudo BACKGROUND: Coded phase-inversion harmonic ultrasonography is a newly available sonographie technique, which is based on a combination of phase-inversion harmonics and coded technology. With the use of a gaiactose-hased sonographic contrast agent, Levowst ~, it clearly depicts vessels in pancreatic tumors. In the present study, we observed the vaseulaniy of pancreatic tumors by means of this techmque and investigated its usefulness for differential diagnosis and evaluation of chemotherapy. METHODS: Forty-five patients with pancreatic tumors underwent contrast-enhanced coded phase-inversion harmonic ultrasonography (CE- US) and contrast-enhanced dynamic computed tomography (CE-CT). CE-US was performed by the use of a GE LOGIQ 9 Series umt (General Electric Medical Systems, Milwaukee. Wl). Levo~.st | (400mg/ml) was injected intravenously as a bolus, When the first microbubble signal appeared in the tumor, images of the ideal scanning plane were displayed in a real- time cominuons fashion and in interval-dday scanning. Nine patients with pancreatic ductal cancers who received chemotherapy with gemcitabnie underwent CE-US once in a month and CE-CT once in 2 months in order to evaluate its effect in terms of tumor size and vascularity. RESULTS: Most pancreatic ductal cancers manifested hypovascular tumors and the other tumors did the isovaseular or the hypervaseular on CE-US. The vascularity of tumors obtained by CE-US was closely correlated with that obtained by CE-CT. Values for sensitivity and specificity in diagnosing pancreatic ductal cancers on CE-US were 86% and 100%, respectively Several fine vessels were observed in 68 % of the hypovascular cancers, although they were relatively sparse to the surrounding pancreatic tissue, The tumor responded to the chemotherapy in 6 of 9 patients treated with gemcitabine. The margin of the 6 tumors was unclear on the fundamental B-mode ultrasonography, while CE-US clearly depicted the margin of the 6 tumors and enabled to measure the tumor size. The reduction of the tumor size measured on CE-US (21 -+ 14 %) as well as CE-CT (13 _+ 6 %) was closely correlated with the reduction of tumor markers such as CA19-9 and CEA. Gemcitabine decreased the amount of tumor vessels in 4 of 6 tumors on CE-US, CONCLUSION: CE- US may play a pivotal role in differential diagnosis of pancreatic tumors and evaluating the effect of chemotherapy in terms of the tumor size and vascularity S1288 Occlusion of Pancreatic Stents: Quantitative Measurement of Sludge Composition and Analysis of Affecting Factors Hongjun Zhang, Tat-Kin Tsang, Willis Parsons, Christy Jack, Jeremy Law, Michael Goldberg Background &Aims: Pancreatic stenting has been increasingly used in various pancreatic disorders, such as ductal obstruction, pancreatitis, and symptomatm pancreas divisum However, stents have to be removed or replaced due to occlusion. Little is known regarding the mechanism of occlusion of pancreatic stents. In order to elucidate the contributing affecting factors and mechanism of pancreatic stent occlusion, we collected the occluded pancreatic stents from patients, and analyzed the composition in the sludge by infrared spectroscopy Methods: 69 occluded pancreatic stents were used in this study. Each stem was cut into 0.5 to lcm segments and carefully observed and the information regarding the occlusion of srents was recorded. The correlations between stem patency and parameters such as stem length, diameter and reasons for stenting were analyzed. Part of the sludge was used to quantify the main chemical compositions by infrared spectroscopy, including protein, cholesterol, calcium carbonate, calcutta phosphate, calcium palmitate and calcium bflimbinate. DNA content in the sludge was also measured using a spectrophotometer. Results: Visual examination showed that most stems were fully occluded with whitish sludge. The average duration time of pancreatic stems is 100.13 days. The results of multivariate analysis demonstrated that the reasons for stentnig, stem length and diameter were not significant factors afl~:cting the patency of stems. The sludge contained a large of amount of protein, which o'n average accounted for 55.5% of dry weight, but average content of total calcium salts in the sludge was only 6.1~ of dry weight Measurement of the DNA content indirectly reflected a minus proportion of bacteria or tissue composition in sludge. Conclusions: The high protein and low calcium salt content ni the sludge of pancreatic stems implies that the mechanism of occlusion in pancreatic stems differs from that of biliary stems Approaches for management of normal or abnormal protein precipitation in pancreatic juice need to be considered in order to prolong the potency of pancreatic stems. $1289 Colorectal Mucosal Histamine Release by Mucosa Oxygenation Compared with Oral Provocation and Established Clinical Tests Martin Raithel, Michael Weidenhiller, Reinhard Abel, Holger Tuchbreiter, Sandra Winterkamp, Norbert Donhauser, Eckhart Hahn It is still very difficult for the gastroenterologist to diagnose gastrointestinal food allergy, since accurate diagnostic criteria for allergy of the gut are lacking~ skin tests and serum IgE detection may fail to detect symptomatic food a|lergy and blinded food challenge procedures are unpopular and both time consuming and cost intensive Materials and Methods: 19 patients suffering from GMA confirmed by blinded oral provocanon were investigated by history, skin puck tests, serum lgE detection and colorectal mucosal histamine release by ex vivo mucosa oxygenation. Intact tissue particles were incubated/stimulated in an oxygenated culture with different food antigens for 30 minutes. Specimens challenged with anti-lgE and without any stimulus served as positive and negative controls. Mucosal histamine release (% of total biopsy histamine content) was considered successful (positive), when the rate of histamine release from biopsies in response to antigens reached more than twice that of the spontaneous release. Histamine measurement was performed by radioimmunoassay. Results: The median (range) of spontaneous histamine release from colorectal mucosa was AGA Abstracts A-188