Purpose: To investigate the utility of Liver Imaging Reporting and Data System (LI-RADS) v2014 for intrahepatic mass-forming cholangiocarcinomas (IMCC) on gadoxetic acid-enhanced magnetic resonance imaging (MRI). Materials and Methods: This retrospective study was approved by our Institutional Review Board with waiver of informed consent. Pathologically confirmed IMCCs (n = 35) and hepatocellular carcinomas (HCCs) (n = 71) in patients with chronic hepatitis B or cirrhosis who had undergone gadoxetic acid-enhanced 3.0T or 1.5T MRI were included. Three radiologists independently assigned LI-RADS categories for each IMCC or HCC. Diagnostic performances of LR-M (probable malignancy, not specific for HCC) and LR-5/5v (definitely HCC) were investigated, and imaging features were compared between IMCCs of LR-M and non-LR-M. Results: In all, 88.6% (31/35), 80.0% (28/35), and 74.3% (26/35) of IMCCs and 12.7% (9/71), 22.5% (16/71), and 16.9% (12/71) of HCCs were assigned as LR-M by the three reviewers with substantial interobserver agreements (kappa = 0.664–0.741). Among IMCCs, 2.9% (1/35), 5.7% (2/35), and 11.4% (4/35) were categorized as LR-5/5v. IMCCs of non-LR-M (n = 8, using the consensus method) were significantly smaller (24.1 ± 17.4 vs. 62.8 ± 30.6 mm, P = 0.002) and showed higher frequencies of arterial hyperenhancement (75.0% (6/8) vs. 7.4% (2/27), P < 0.001) and lower frequencies of non-HCC malignancy-favoring features such as peripheral enhancement (12.5% (1/8) vs. 77.8% (21/27), P = 0.002) or the target appearance on the hepatobiliary phase (0% (0/8) vs. 81.5% (22/27), P < 0.001) than IMCCs of LR-M (n = 27). Conclusion: Using LI-RADS, the majority of IMCCs can be accurately categorized as LR-M on gadoxetic acid-enhanced MRI; however, caution is warranted, as some atypical IMCCs may be assigned as LR-5/5v resulting in a false-positive diagnosis of HCC. J. Magn. Reson. Imaging 2016;44:1330–1338.
- intrahepatic mass-forming cholangiocarcinoma
- portal venous phase