LI-RADS nonradiation treatment response assessment version 2024: diagnostic performance in HCC treated with transarterial chemoembolization.

[BACKGROUND AND OBJECTIVES] The 2024 version of the Liver Imaging Reporting and Data System (LI-RADS) Treatment Response Assessment (TRA) introduces two distinct algorithms: nonradiation TRA and radiation TRA. We aimed to assess the diagnostic performance of LI-RADS v2024 nonradiation TRA in evaluating hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE).

[METHODS] This retrospective single-center study enrolled 167 patients (mean age, 59 years ± 10 (standard deviation), 136 men) with HCC who underwent TACE followed by surgery. Post-treatment contrast-enhanced MRI was independently evaluated by two radiologists using the LI-RADS 2024 nonradiation TRA algorithm. Histopathologic results (complete necrosis (44/191) vs. incomplete necrosis [147/191]) served as the reference standard. Sensitivity, specificity, and accuracy of LI-RADS Treatment Response (LR-TR) categories were calculated. The impact of ancillary features (AFs) on diagnostic performance was analyzed using the McNemar test.

[RESULTS] For predicting incomplete necrosis, the LR-TR Viable category showed a sensitivity of 70.1% (95% CI: 0.63-0.77) and specificity of 97.7% (95% CI: 0.93-0.98). For predicting complete necrosis, the LR-TR Nonviable category demonstrated a sensitivity of 77.3% (95% CI: 0.65-0.90) and specificity of 81.0% (95% CI: 0.75-0.87). Incorporating AFs significantly improved sensitivity for detecting incomplete necrosis (77.6% vs. 70.1%, p = 0.003) without compromising specificity (88.6% vs. 97.7%, p = 0.134).

[CONCLUSION] LI-RADS v2024 nonradiation TRA demonstrated good diagnostic performance in assessing HCC response after TACE. The use of AFs enhanced sensitivity for detecting residual viable tumors, supporting their clinical utility in equivocal cases.

[KEY POINTS] Question The diagnostic performance of the 2024 updated Liver Imaging Reporting and Data Systems (LI-RADS) Treatment Response Assessment (TRA), particularly the role of ancillary features (AFs), requires evaluation. Findings LI-RADS v2024 nonradiation TRA performed well in predicting histopathologic necrosis, with AFs significantly improving sensitivity for viability prediction. Clinical relevance The application of AFs is recommended to optimize post-TACE assessment and clinical decision-making for HCC management.