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. Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:731–740.