Prospective intra-individual comparison of MRI with gadoxetic acid and extracellular agent for LI-RADS v2018 categorization of hepatocellular carcinoma: Added value of late portal venous phase in gadoxetic acid-enhanced MRI

Purpose To compare the Liver Imaging Reporting and Data System (LI-RADS) v2018 categorization of hepatocellular carcinoma (HCC) between gadoxetic acid–enhanced magnetic resonance imaging (EOB-MRI) with the addition of the late portal venous phase (LPVP) and extracellular agent–enhanced MRI (ECA-MRI). Methods This prospective study enrolled 43 high-risk patients with 47 pathologically proven HCCs who underwent both EOB-MRI and ECA-MRI within a 76-day interval. EOB-MRI included additional LPVP imaging (mean, 101.37 ± 8.74 s after gadoxetic acid injection; range, 90–119 s). Two independent radiologists assessed the major features by consensus. LI-RADS v2018 categorization for HCC was performed using ECA-MRI (LI-RADS-ECA), EOB-MRI (LI-RADS-EOB), and modified EOB-MRI including LPVP (modified LI-RADS-EOB [mLI-RADS-EOB]) Results Compared with ECA-MRI, EOB-MRI showed a lower frequency of washout appearance (WA) ( P  = 0.012) and enhancing capsule (EC) ( P  = 0.006) in HCC. The frequencies of WA ( P  > 0.999) and EC ( P  > 0.999) were similar between the ECA-MRI and modified EOB-MRI. The sensitivity for LR-5 categorization with LI-RADS-ECA did not differ significantly from that of either LI-RADS-EOB ( P  = 0.125) or mLI-RADS-EOB ( P  > 0.999). Sensitivity for LR-5 assignment was slightly better in mLI-RADS-EOB than in LI-RADS-EOB ( P  = 0.063). Conclusion Including the LPVP in EOB-MRI could improve the identification of WA and EC in HCCs to a frequency similar to that of ECA-MRI, and it slightly increased the sensitivity of LR-5 assignment to be comparable to that of ECA-MRI.