Liver Imaging Reporting and Data System on CT and gadoxetic acid-enhanced MRI with diffusion-weighted imaging

To assess major imaging features of Liver Imaging Reporting and Data System (LI-RADS) on contrast-enhanced CT and gadoxetic acid-enhanced MRI and to estimate whether the combination of signal intensity favouring HCC on hepatobiliary phase (HBP) and diffusion-weighted images (DWI) can act as a major feature in LI-RADS. Four hundred twenty one patients with 445 observations were included. Major features of LI-RADS on CT and MRI as well as HBP and DWI features were assessed. Diagnostic performances of LR-5 according to LI-RADS v2014 and modified LI-RADS which incorporate combination of HBP and DWI were assessed. Pairwise comparisons of the receiver operating characteristic (ROC) curves were performed. For HCCs, capsule appearance had the highest rate of discordance between CT and MRI (32.7%), followed by washout appearance (22.2%). Specificity (75%) of LR-5 of LI-RADS v2014 was lower than that (77.1-79.2%) of modified LI-RADS. Area under the ROC curve of modified LI-RADS (0.755-0.775) was not significantly different from that of LI-RADS v 2014 (0.709) (p > 0.05). There were substantial discordances between CT and MRI for capsule and washout appearances in hepatic observations, and combination of gadoxetic acid-enhanced MRI and DWI might be able to be incorporated as a major feature of LI-RADS. (orig.)