Nomogram Estimating Vessels Encapsulating Tumor Clusters in Hepatocellular Carcinoma From Preoperative Gadoxetate Disodium‐Enhanced MRI

Background Vessels encapsulating tumor clusters (VETC) pattern is a novel microvascular pattern associated with poor outcomes of hepatocellular carcinoma (HCC). Preoperative estimation of VETC has potential to improve treatment decisions. Purpose To develop and validate a nomogram based on gadoxetate disodium‐enhanced MRI for estimating VETC in HCC and to evaluate whether the estimations are associated with recurrence after hepatic resection. Study Type Retrospective. Population A total of 320 patients with HCC and histopathologic VETC pattern assessment from three centers (development cohort:validation cohort = 173:147). Field Strength/Sequence A3.0 T/turbo spin‐echo T2 ‐weighted, spin‐echo echo‐planar diffusion‐weighted, and 3D T1 ‐weighted gradient‐echo sequences. Assessment A set of previously reported VETC‐ and/or prognosis‐correlated qualitative and quantitative imaging features were assessed. Clinical and imaging variables were compared based on histopathologic VETC status to investigate factors indicating VETC pattern. A regression‐based nomogram was then constructed using the significant factors for VETC pattern. The nomogram‐estimated VETC stratification was assessed for its association with recurrence. Statistical Tests Fisher exact test, t ‐test or Mann–Whitney test, logistic regression analyses, Harrell's concordance index (C‐index), nomogram, Kaplan–Meier curves and log‐rank tests. P value < 0.05 was considered statistically significant. Results Pathological VETC pattern presence was identified in 156 patients (development cohort:validation cohort = 83:73). Tumor size, presence of heterogeneous enhancement with septations or with irregular ring‐like structures, and necrosis were significant factors for estimating VETC pattern. The nomogram incorporating these indicators showed good discrimination with a C‐index of 0.870 (development cohort) and 0.862 (validation cohort). Significant differences in recurrence rates between the nomogram‐estimated high‐risk VETC group and low‐risk VETC group were found (2‐year recurrence rates, 50.7% vs. 30.3% and 49.6% vs. 31.8% in the development and validation cohorts, respectively). Data Conclusion The nomogram integrating gadoxetate disodium‐enhanced MRI features was associated with VETC pattern preoperatively and with postoperative recurrence in patients with HCC. Evidence Level 4 Technical Efficacy Stage 2