Liver Imaging Reporting and Data System v2014 Categorization of Hepatocellular Carcinoma on Gadoxetic Acid-Enhanced MRI: Comparison With Multiphasic Multidetector Computed Tomography

Purpose: To investigate the Liver Imaging Reporting and Data System (LI-RADS) v2014 categorization of hepatocellular carcinomas (HCCs) on gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) in comparison with multiphasic multidetector computed tomography (MDCT). Materials and Methods: Our Institutional Review Board approved this retrospective study and waived the requirement for informed consent. We included 182 high-risk patients with 216 pathologically confirmed HCCs who underwent both Gd-EOB-MRI at 1.5 or 3T and multiphasic MDCT. Two independent radiologists assessed the presence or absence of major HCC features and assigned LI-RADS categories before and after considering ancillary features on both MRI and MDCT. Finally, sensitivities of LR-5/5v and frequencies of major HCC features were compared between MRI and MDCT using the McNemar test. Results: Sensitivities of LR-5/5v were not significantly different between MRI and MDCT (63.4% [137/216] vs. 64.4% [139/216], P = 0.831; 60.6% [131/216] vs. 60.6% [131/216], P = 0.868, for reviewers 1 and 2, respectively). Among major HCC features seen on consensus review, washout and capsule appearance were less frequently observed on MRI than on MDCT (69.0% [149/216] vs. 87.0% [188/216], P < 0.001 and 17.1% [37/216] vs. 31.5% [68/216], P < 0.001), while no significant differences were found for arterial hyperenhancement (88.9% [192/216] vs. 84.7% [183/216], P = 0.081). Ancillary features led to category changes in 18.1% (39/216) of nodules on MRI (all, LR-3 to LR-4), while no changes were seen on MDCT. Conclusion: Using LI-RADS, Gd-EOB-MRI showed comparable sensitivity to multiphasic MDCT for the diagnosis of HCCs, and ancillary features of MRI frequently led to the upgrade of nodules from LR-3 to LR-4.