MRI ‐Based Score to Predict Retreatment Response for Viable Hepatocellular Carcinomas After Transarterial Chemoembolization

ABSTRACT Background & Aims Predicting retreatment response of viable tumours after transarterial chemoembolization (TACE) is critical for personalised treatment and prognosis assessment in hepatocellular carcinoma (HCC). We aimed to develop an MRI‐based prediction model for viable tumour response. Methods This retrospective multicentre study included patients with HCC who presented with viable tumours 1 month after initial TACE between February 2015 and October 2022. In addition, data from a prospective clinical trial were reanalyzed as an external validation cohort. All patients underwent contrast‐enhanced MRI at baseline (for initial HCC assessment), at 1 month (for evaluation of viable tumour characteristics) and at 6 months (for assessment of treatment response). The training set ( n = 167) and test set ( n = 59) were used to build lesion‐ and patient‐level models predicting retreatment response at 6 months via logistic regression. Risk groups were stratified by the Youden index and analysed across retreatment subgroups. Results The Viable tumour Imaging Traits for Assessing Likelihood of response (VITAL) model incorporated four features: diffusion restriction ( p = 0.050; 1 point), peritumoral hyperenhancement ( p = 0.002; 1 point), heterogeneity ( p < 0.001; 2 points) and mural nodule ( p = 0.004; 2 points if absent). The model achieved AUCs of 0.821 (95% CI: 0.760–0.882) and 0.733 (95% CI: 0.602–0.865) in training and test cohorts. The patient‐level VITAL‐P Score was calculated as: 1 × (largest viable tumour size + viable tumour number) + 3 × VITAL Score. High‐risk patients (VITAL‐ p ≥ 16) had significantly shorter overall survival (OS) in the overall cohort ( p = 0.021) and shorter progression‐free survival (PFS)and OS compared with low‐risk patients in the locoregional therapy subgroup ( p = 0.021 and 0.002, respectively). Conclusions The prediction model based on imaging features of post‐TACE viable HCCs demonstrates strong predictive power for tumour retreatment response at 6 months and correlates well with prognosis.