Inter-observer Agreement for the Diagnosis of LI-RADS 3 and 4 Lesions on Gadoxetate MRI and Outcome Assessment

Motivation: Despite standardization by LI-RADS v2018, inter-observer variability persists in diagnosing liver lesions, especially for indeterminate lesions (LR-3 and 4), impacting patient outcomes. Goal(s): Assess inter-observer agreement in diagnosing LR-3 and 4 lesions on gadoxetate-enhanced MRI, describe lesion outcomes, and identify malignancy-predictive imaging features. Approach: A retrospective single-center study (n=111) analyzed inter-observer agreement, outcomes, and malignancy-predicting imaging features of LR-3 and 4 lesions. Results: Inter-observer agreement was poor for LR-3 (kappa 0.27) and fair for LR-4 (kappa 0.43). Malignancy developed in 29% of LR-3 and 60% of LR-4 lesions; LR-4 lesions progressed to HCC faster (median 18 vs. 31 months, p=0.01). Impact: The study highlights the need for improved standardization and radiologist's training in applying LI-RADS criteria to enhance diagnostic accuracy.