Peripheral cholangiocarcinoma: comparison of MRI with CT.

To evaluate the clinical utility of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of peripheral cholangiocarcinoma of the liver, 11 patients with pathologically proven peripheral cholangiocarcinoma were examined with both CT and MRI. On CT scans in 10 cases, the tumors appeared as irregular, low-attenuation masses with a wide variation in heterogeneity. Contrast enhancement of the tumors was mild in nine cases and moderate in one case, at the periphery. Tumor was not identified in one case. On T1-weighted MRIs, the tumors showed low intensity in eight cases and isointensity in three cases. On T2-weighted images, the tumors showed high intensity in all 11 cases. Focal dilatation of the intrahepatic bile ducts around the tumor was seen in one case on MRIs and in four cases on CT scans. Portal vein invasion of the tumors was seen in one case, and lymphadenopathy was seen in four cases on both MRIs and CT scans. MRI was slightly superior to CT in detecting the tumors, was inferior to CT in delineating focal ductal dilatation around the tumors, and was equal to CT in assessing extent of the tumors.