Imaging features of intrahepatic mass-forming cholangiocarcinomas on Gd-BOPTA-enhanced MRI

Objective: The purpose is to describe the imaging features of intrahepatic mass-forming cholangiogcarcinoma (IMC) with emphasis on hepatobiliary phase (HBP) on Gd-BOPTA-enhanced MR imaging. Methods: We retrospectively reviewed 93 patients with pathologically proven IMCs with MR hepatocyte-specific contrast agent Gd-BOPOTA. We evaluated the enhancement pattern, degree of enhancement and conspicuity of IMCs. We also analyzed diffusion-weighted (DW) images and measured the apparent diffusion coefficient (ADC) values of IMCs. Results: 80 (86.0%) lesions exhibited peripheral enhancement in arterial phase followed by progressive enhancement in portal venous and delayed phases. On HBP, 85 (91.4%) lesions exhibited peripheral hypointensity with central hyperintensity. On HBP, IMCs exhibited the highest conspicuities, and the degrees of enhancement were higher in moderately differentiated tumors (48.2% +/- 15.6%) than in poorly differentiated tumors (35.5% +/- 18.9%) and in the lesions without lymph node metastasis (47.6% +/- 18.8%) than with lymph node metastasis (33.7% +/- 19.6%). Additionally, the ADCs of poorly differentiated tumors were lower than those of moderately differentiated tumors. Conclusion: The typical pattern of IMCs on Gd-BOPTA-enhanced images HBP images was peripheral hypointensity with central hyperintensity. IMCs exhibited better delineation on HBP images, and the ADCs of poorly differentiated IMCs were lower, which may aid reasonable surgical planning and improve prognoses.