Updates on LI-RADS Treatment Response Criteria for Hepatocellular Carcinoma: Focusing on MRI

As the incidence of hepatocellular carcinoma (HCC) and subsequent treatments with liver-directed therapies rise, the complexity of assessing lesion response has also increased. The Liver Imaging Reporting and Data Systems (LI-RADS) treatment response algorithm (LI-RADS TRA) was created to standardize the assessment of response after locoregional therapy (LRT) on contrast-enhanced CT or MRI. Originally created based on expert opinion, these guidelines are currently undergoing revision based on emerging evidence. While many studies support the use of LR-TRA for evaluation of HCC response after thermal ablation and intra-arterial embolic therapy, data suggest a need for refinements to improve assessment after radiation therapy. In this manuscript, we review expected MR imaging findings after different forms of LRT, clarify how to apply the current LI-RADS TRA by type of LRT, explore emerging literature on LI-RADS TRA, and highlight future updates to the algorithm. Evidence Level3. Technical EfficacyStage 2.

Automated summary

With the increase in hepatocellular carcinoma (HCC) and liver-directed therapies, the assessment of lesion response has become more complex. The Liver Imaging Reporting and Data Systems (LI-RADS) treatment response algorithm (LI-RADS TRA) was created to standardize the evaluation of response after locoregional therapy (LRT) using contrast-enhanced CT or MRI. This article reviews the expected MR imaging findings after different forms of LRT, explains the application of LI-RADS TRA for different types of LRT, explores emerging literature on LI-RADS TRA, and highlights future updates to the algorithm.