S1160 Comparative Performance Assessment of Gastroenterologist and Radiologist in the Detection of Polyps in CT Colonography with Two Different Preparations

went presurgical dynamic CT perfusions. Data were analysed to calculate tumor and normal pancreatic blood flow, blood volume, mean transit time and permeability surface. CT perfusion parameters were compared with following histopathological parameters of resected specimens: intratumoral microvascular density, WHO classification, tumor size, tumor proliferation index, hormonal profile and occurrence of metastasis. Spearman's correlation coefficient was used to correlate perfusion values with microvascular density and Mann-Whitney tests 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 not compatible with perfusion postprocessing. High correlation (r = 0.620, p < 0.001) was observed between tumor blood flow and intratumoral microvascular density. Blood flow was significantly higher (p = 0.02) in the group of benign tumors than in the groups of indeterminate prognosis or well differentiated carcinomas. Blood flow was significantly higher in tumors with proliferation index ≤ 2 % (p = 0.005) and without histological signs of angioinvasion (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 tumors with lymph nodes or liver metastasis (p = 0.02; p = 0.05). The sensitivity and specificity of blood flow (threshold value = 82mL/100g/min) in identifying well-differentiated endocrine carcinomas was 40 % and 80 % respectively. Conclusion: Results suggest that CT perfusion is feasible in Pancreatic Endocrine Tumors and allows to evaluate tumor angiogenesis by predicting microvascular density. CT perfusion measurements are related to the main histopronostic factors, such as the proliferation index and the WHO classification.