LI-RADS treatment response algorithm for detecting incomplete necrosis in hepatocellular carcinoma after locoregional treatment: a systematic review and meta-analysis using individual patient data.

To perform a systematic review and meta-analysis using individual patient data to investigate the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) Treatment Response (TR) algorithm for detecting incomplete necrosis on pathology. PubMed and EMBASE were searched from Jan 1, 2017 until October 14, 2020. Studies reporting diagnostic accuracy of LI-RADS TR algorithm on CT or MRI for detecting incomplete necrosis on pathology as a reference standard were included. Sensitivity and specificity were pooled using random-effects model. Subgroup analyses were performed for locoregional treatment (LRT) type and imaging modality. Six studies (393 patients, 534 lesions) were included. Pooled sensitivity was 0.56 (95% confidence interval [CI] 0.43–0.69) and specificity was 0.91 (95%CI 0.84–0.96). Pooled sensitivity was highest using arterial phase hyperenhancement (APHE) (0.67 [95%CI 0.51–0.81]), followed by washout (0.43 [95%CI 0.26–0.62]) and enhancement similar to pretreatment (0.24 [95%CI 0.15–0.36]). Among lesions with incomplete necrosis, 2% (95%CI 0.00–0.05) manifested as washout but no APHE; 0% (95% CI 0.00–0.02) as enhancement similar to pretreatment without both APHE and washout. Pooled sensitivity was lower after ablation than embolization (0.42 [95%CI, 0.28–0.57] vs. 0.65 [95%CI, 0.53–0.77], p = 0.033). MRI and CT were comparable (p = 0.783 and 0.290 for sensitivity and specificity). LI-RADS TR algorithm shows moderate sensitivity and high specificity for detecting incomplete necrosis after LRT. APHE is the dominant criterion, a washout contributes to small but meaningful extent, while the contribution of enhancement similar to pretreatment may be negligible. LRT type may affect performance of the algorithm.