LI-RADS v2018: utilizing ancillary features on gadoxetate-enhanced MRI to modify final LI-RADS category

Purpose: To quantify how often the LI-RADS v2018 category changed when utilizing major features only, when utilizing major and ancillary features, and when utilizing major and ancillary features excluding gadoxetate-specific ancillary features. Methods: Retrospective analysis of 100 patients age 18 and older at high risk for hepatocellular carcinoma who had an MRI abdomen performed with intravenous contrast gadoxetate between 1/1/2017 and 3/23/2018. Each examination was reviewed by a body fellowship-trained radiologist. LI-RADS category was assigned to the liver observation after review of major features only. Ancillary features were then reviewed and LI-RADS category assigned both including and excluding ancillary features specific to gadoxetate. Results: Utilizing all MRI ancillary features, including those specific to gadoxetate, changed the final LI-RADS category in 56.4% of liver observations, the majority an increase or decrease from LR-3. When not including the ancillary features specific to gadoxetate, the final LI-RADS category changed in 30.9% of observations, the majority increasing from LR-3 to LR-4. Conclusion: Utilizing LI-RADS v2018 ancillary features can significantly alter the final LI-RADS category, especially when using gadoxetate-specific ancillary features. Understanding the correct application of ancillary features for the final LI-RADS category helps implement a more consistent category assessment amongst users.