Ito K, et al. - The diagnostic accuracy of multidetector-row computed tomography (MDCT), mapping biopsy, and other imaging modalities was investigated to predict the longitudinal extension and depth of invasion of extrahepatic cholangiocarcinoma at possible surgical ductal margins. For longitudinal cancer spread, the diagnostic accuracy of MDCT was 79.7%, that of biopsy was 73.0%, and combining the two modalities showed highest accuracy (83.8%). The depth of tumor invasion could be predicted by combination of the ductal wall thickness and contrast enhancement on MDCT, that is, at 11 of 13 sites (84.6%) with submucosal invasion, ductal wall thickness was > 2.5 mm with high contrast enhancement. Findings thereby indicate that in patients with extrahepatic cholangiocarcinoma, MDCT had the highest accuracy for diagnosing longitudinal extension at possible surgical ductal margins. Ductal wall thickness and contrast enhancement of MDCT might predict the depth of tumor invasion.