mean age, 53 years; range, 18-78 years) with resecable endocrine pancreatic tumors under-went presurgical dynamic CT perfusions. Data were analysed to calculate tumor and normalpancreatic blood flow, blood volume, mean transit time and permeability surface. CT perfu-sion parameters were compared with following histopathological parameters of resectedspecimens: intratumoral microvascular density, WHO classification, tumor size, tumor prolif-eration index, hormonal profile and occurrence of metastasis. Spearman's correlation coeffi-cient was used to correlate perfusion values with microvascular density and Mann-Whitneytests was used for the other radiologic-pathologic association. Results: 28 patients (77.8 %)were finaly included in the study; eight were excluded because of artifacts that were notcompatible with perfusion postprocessing. High correlation (r = 0.620, p < 0.001) wasobserved between tumor blood flow and intratumoral microvascular density. Blood flowwas significantly higher (p = 0.02) in the group of benign tumors than in the groups ofindeterminate prognosis or well differentiated carcinomas. Blood flow was significantly higherin tumors with proliferation index ≤ 2 % (p = 0.005) and without histological signs ofangioinvasion (p = 0.008). Tumors measuring less than 2 cm had higher blood flow (p <0.001) and shorter mean transit time (p = 0.03). Mean transit time was longer in tumorswith lymph nodes or liver metastasis (p = 0.02; p = 0.05). The sensitivity and specificityof blood flow (threshold value = 82 mL/100g/min) in identifying well-differentiated endocrinecarcinomas was 40 % and 80 % respectively. Conclusion: Results suggest that CT perfusionis feasible in Pancreatic Endocrine Tumors and allows to evaluate tumor angiogenesis bypredicting microvascular density. CT perfusion measurements are related to the main histop-ronostic factors, such as the proliferation index and the WHO classification.

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Comparative Performance Assessment of Gastroenterologist and Radiologist inthe Detection of Polyps in CT Colonography with Two Different PreparationsKoichi Nagata, Tomohiko Okawa, Akihiro Honma, Shungo Endo, Shin-ei Kudo, HiroyukiYoshida

PURPOSE: This prospective study compared the performance of a gastroenterologist withthat of a radiologist in the detection of polyps in 64-slice multidetector CT colonographyimages of patients who underwent two types of preparations. METHODS: Forty patientswith a positive fecal occult blood test or a bright red blood per rectum were randomlyallocated to either a same-day-preparation group (n=20) or a reduced-bowel-preparationgroup (n=20). The same-day preparation consisted of administration of 2L polyethyleneglycol solution in the morning of CT scanning with 20ml of water-soluble sodium/meglumine-diatrizoate contrast-medium (Gastrografin) for fecal tagging. No dietary restriction wasapplied. The reduced-bowel preparation consisted of oral administration of Gastrografin ateach low-fiber meal for 3 days prior to the CT scanning. Patients received a total of 45mlcontrast medium during the 3 days, and 10ml of Sodium picosulfate solution before thenight of the CT scanning. In both groups, optical colonoscopy was performed after the CTscanning and was used as the references standard. CT images were reviewed by a board-certified gastroenterologist (KN) and a board-certified radiologist (TO) for finding polyps≧6mm, and their per-polyp sensitivities and false positive findings were calculated basedon the reference standard. RESULTS: In the same-day-preparation group, optical colonoscopyfound 8 carcinomas/adenomas ≧10mm and 11 adenomatous/hyperplastic polyps that were6-9mm in size. In the reduced-bowel-preparation group, 4 carcinoma/adenomas≧10mm and7 adenomatous/hyperplastic polyps 6-9mm in size were confirmed by optical colonoscopy. InCT colonography of the same-day-preparation group, per-polyp sensitivities of the gastroen-terologist and the radiologist were 91% and 73%, respectively, for 6-9mm polyps. Per-polypsensitivities of the gastroenterologist and the radiologist in the reduced-bowel-preparationgroup were 86% and 86%, respectively, for 6-9mm polyps. In both preparation groups,sensitivities of the two readers were 100% for polyps ≧10mm. In same-day-preparationgroup, false positive findings per patient for the gastroenterologist and the radiologist were0.15 and 0.1, respectively, while those of reduced-bowel-preparation group were 0.3 and0.2, respectively. CONCLUSIONS: Both gastroenterologist and radiologist were able to detectpolyps ≧10mm at 100% sensitivity in both preparations, while the gastroenterologist foundmore medium-size polyps. CT colonography with reduced-bowel preparation had less sensit-ivity for medium-size polyps and generated more false positive than the same-day preparation.

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Detection of Cholangiocarcinoma In-Vivo Using Miniprobe-Based ConfocalMicroscopyAlexander Meining, Eckart Frimberger, Valentin Becker, Stefan von Delius, Claus vonWeyhern, Roland M. Schmid, Christian Prinz

Background: The preoperative diagnosis of cholangiocarcinomas is associated with a lowaccuracy. To overcome these limitations, a new imaging modality was developed and evalu-ated to detect neoplasia In Vivo in the biliary tract. Methods: Mucosal imaging was performedwith a confocal laser scanning miniprobe after intravenous injection of fluorescein 1%. Afteran initial feasibility study performed in two pigs, 14 patients with biliary strictures wereexamined In Vivo with a specially designed miniaturized confocal laser probe thin enoughto be inserted through the accessory channel of a peroral cholangioscope. Results: Presenceof irregular vessels was the laser microscopic hallmark able to predict neoplasia with anaccuracy of 91.7%. Confocal microscopy was thereby superior to histopathology of biopsyspecimens taken from strictures (accuracy: 76.9%). Mean signal-to-noise-ratio of laser micro-scopic images acquired from malignant strictures differed significantly from those of benignorigin (p=0.003). Figure shows confocal laser scanning microscopic images in patients withbenign (a, b) or malignant strictures (c, d). Field of view is 240 x 240 µm. Benign findingsare characterized by reticular arrangement of dark-grey bands on a light-grey background.In contrast, malignancy is characterized by a black/dark-grey-background with irregularlarge white streaks (blood vessels filled with fluorescein). Conclusions: The methodologydescribed represents a promising and reproducible diagnostic imaging approach for thedetection of cancers even in small ducts such as the biliary system. This new tool could beof upmost importance as cholangiocarcinoma remains one of the cancers with the poor-est prognosis.

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Confocal Laser Endomicroscopy Is An Effective and Safe Diagnostic Tool inGI-EndoscopyRalf Kiesslich, David P. Hurlstone, Kerry B. Dunbar, Marcia I. Canto, Martin Goetz,Arthur Hoffman, Michael Vieth, Stefan Biesterfeld, Peter R. Galle, Markus F. Neurath

Introduction: Confocal laser endomicroscopy (CLE) is a diagnostic tool for In Vivo histologyduring ongoing endoscopy. Surface and subsurface In Vivo architecture of the gut can beused for immediate In Vivo tissue diagnosis. Aim of the current study was the evaluation ofdiagnostic possibilities and safety of CLE at three different centers. Methods: CLE underanalgosedation (EC-3870CIFK; Pentax, Tokyo, Japan; excitation of 488nm solid state laser;detection >515 nm; optical slice thickness 7µm; lateral resolution 0.7µm; frame rate 0.8 or1.6 frames/sec)was performed in the upper and lower GI tract. Intravenous Fluorescein[10%], topical Acriflavine [0.05%] and cresyl violet [1%] were used as contrast agents.Initial endoscopic diagnosis was made based on the macroscopic appearance. Subsequently,confocal images were graded according to confocal pattern classifications or based on knownhistopathology changes for the presence of normal, inflammatory, regenerative and (pre)neo-plastic changes. Optical biopsies were followed by targeted biopsies. Complications wereprospectively evaluated. Results: 2102 CLE examinations (excluding 41 technical failures)were performed between 8/03-11/07 in 1771 patients [866 upper, 1236 lower endoscopies]at the three centres. Systemic Fluorescein was used in 1592, topical Acriflavine in 254,topical cresyl violet in 60 and in 196 procedures a combined staining method was used.Cellular, vascular and connective tissue changes of mucosa could be observed In Vivo. Thus,endoscopy, endomicroscopy, histopathology and clinical data revealed 422 cases with Refluxdisease (including Barrett's esophagus); esophageal dysplasia and cancer 94; gastritis 75;gastric dysplasia and cancer 22; celiac disease 39; MALT lymphoma 9; IBD 893; microscopiccolitis 42; adenoma 206; colon cancer 99; GVHD 14; others/normal 187. The overall accuracyrates for CLE based In Vivo diagnosis was 91% in the upper and 93% in the lower GI tract.Initial macroscopic diagnosis changed in 32% (upper) and 22% (lower GI tract) based onmicroscopic evaluation. Complications occurred in 22 patients (1.0%) and were related toendoscopic resections (4 perforations, 4 bleedings),systemic Fluorescein application (nausea5; decreased blood pressure 9). All Patients reported a transient discoloration of the skinand urine after Fluorescein application. No photo toxicity or procedure related deaths werenoted. Conclusions:CLE is a safe and effective method based on more than 2000 examina-tions. CLE expands diagnostic possibilities from macroscopic surface visualization to micro-scopic subsurface analysis adding clinical relevant diagnostic criteria during endoscopy.

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High-Resolution Endoscopy Plus Chromoendoscopy or Narrow-Band Imagingin the Detection of Dysplasia and Colonic Cancer in Long StandingInflammatory Bowel Disease: A Prospective Randomized Crossover Studymaria pellise, Michel Zabalza, Cristina Rodriguez de Miguel, Miquel Sans, MontserratAceituno, Elena Ricart, Gloria Fernandez-Esparrach, Angels Gines, Oriol Sendino, JosepM. Bordas, Josep M. Pique, Julian Panes, Josep Llach

Background: Chromoendoscopy (CE) has been shown to be the standard of use for patientswith long standing inflammatory bowel disease. Narrow band imaging (NBI) is a noveltechnique that enhances the diagnostic capability of endoscopes in characterizing tissues.Aim: To compare NBI with CE for the early detection of dysplasia and colitis-associatedcolon carcinomas in patients with long-standing ulcerative colitis (UC) or colonic Crohndisease (CD). Patients and methods: All patients with clinically inactive, UC or CD (≥ 9years) controlled at the hospital have been recruited. Patients have been submitted to both,high-definition indigo carmine pancolonoscopy and high-definition colonoscopy with NBI,in a period of time no longer than 2 months. Order of the examination has been randomized(1:1). In each exploration targeted biopsies have been obtained from abnormal areas. Astopwatch has been used to record the withdrawal time. Number of biopsies and character-istics of the lesions have been registered. Pathological exam was considered as gold standard.Results: Eighty patients were considered from which 20 had to be excluded because of poorbowel preparation (n = 6), presence of endoscopic activity in one of the explorations (n =11), and refuse to complete the study protocol (n = 3). Baseline characteristic of the 60 patientsincluded were: male/female n = 33/27; mean age 48.4 ± 13.9 yrs , UC/CD/indeterminate colitisn = 40/19/1, pancolitis/left colitis n = 43/17, disease duration 16.0 ± 8.0 yrs. No high gradedysplasia nor carcinoma were detected. See table. Conclusions: NBI can represent a lesstime-consuming and equally effective alternative to CE for the discrimination of neoplasiain patients with long standing inflammatory bowel disease even if this technique is harboredby a minor sensitivity for the detection of suspicious lesions.

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