Intrahepatic cholangiocarcinoma: MRI and pathologic correlation in 14 patients.

PURPOSE: Our goal was to determine the MR features of intrahepatic cholangiocarcinoma and to correlate them with pathologic findings in a surgical series.

METHOD: MRI in 14 patients with intrahepatic cholangiocarcinoma who had undergone resection was reviewed. All patients had T1- and T2-weighted SE sequences. Contrast-material-enhanced MRI was performed in 12 cases. Comparison between findings at MRI and pathologic examination was made.

RESULTS: MRI depicted all the lesions but one satellite nodule of 2 cm diameter. All lesions were hypointense relative to the liver on T1-weighted images. On T2-weighted images, the tumors were predominantly isointense or slightly hyperintense relative to liver parenchyma in nine cases (64%) and were strongly hyperintense in five cases (36%). Central hypointense areas or bands were seen in eight cases. No capsule was detected. On contrast-enhanced MR studies, all lesions had progressive and concentric filling with contrast material. Associated findings such as vascular encasement, focal liver atrophy, or dilatation of intrahepatic bile ducts were observed in 10 cases (71%). Comparison with pathologic examination revealed that lesion signal intensity on T2-weighted MR images was due mostly to the amount of fibrosis, necrosis, and mucous secretion within the lesion. The nine isointense or slightly hyperintense lesions contained abundant fibrosis and had a low content of mucous secretion or necrosis, whereas the five hyperintense lesions contained low or moderate fibrosis and prominent mucous secretion and/or necrosis.

CONCLUSION: Our study suggests that the MR features of intrahepatic cholangiocarcinoma are well correlated with pathologic findings, but are nonspecific. Associated findings may strengthen the diagnosis of intrahepatic cholangiocarcinoma at MRI.