Preoperative Gadoxetic Acid‐Enhanced MRI Features for Evaluation of Vessels Encapsulating Tumor Clusters and Microvascular Invasion in Hepatocellular Carcinoma: Creating Nomograms for Risk Assessment

Background Vessels encapsulating tumor cluster (VETC) and microvascular invasion (MVI) have a synergistic effect on prognosis assessment and treatment selection of hepatocellular carcinoma (HCC). Preoperative noninvasive evaluation of VETC and MVI is important. Purpose To explore the diagnosis value of preoperative gadoxetic acid (GA)‐enhanced magnetic resonance imaging (MRI) features for MVI, VETC, and recurrence‐free survival (RFS) in HCC. Study Type Retrospective. Population 240 post‐surgery patients with 274 pathologically confirmed HCC (allocated to training and validation cohorts with a 7:3 ratio) and available tumor marker data from August 2014 to December 2021. Field Strength/Sequence 3‐T, T1‐, T2‐, diffusion‐weighted imaging, in/out‐phase imaging, and dynamic contrast‐enhanced imaging. Assessment Three radiologists subjectively reviewed preoperative MRI, evaluated clinical and conventional imaging features associated with MVI+, VETC+, and MVI+/VETC+ HCC. Regression‐based nomograms were developed for HCC in the training cohort. Based on the nomograms, the RFS prognostic stratification system was further. Follow‐up occurred every 3–6 months. Statistical Tests Chi‐squared test or Fisher's exact test, Mann–Whitney U‐test or t ‐test, least absolute shrinkage and selection operator–penalized, multivariable logistic regression analyses, receiver operating characteristic analysis, Harrell's concordance index (C‐index), Kaplan–Meier plots. Significance level: P < 0.05. Results In the training group, 44 patients with MVI+ and 74 patients with VETC+ were histologically confirmed. Three nomograms showed good performance in the training (C‐indices: MVI+ vs. VETC+ vs. MVI+/VETC+, 0.892 vs. 0.848 vs. 0.910) and validation (C‐indices: MVI+ vs. VETC+ vs. MVI+/VETC+, 0.839 vs. 0.810 vs. 0.855) cohorts. The median follow‐up duration for the training cohort was 43.6 (95% CI, 35.0–52.2) months and 25.8 (95% CI, 16.1–35.6) months for the validation cohort. Patients with either pathologically confirmed or nomogram‐estimated MVI, VETC, and MVI+/VETC+ suffered higher risk of recurrence. Data Conclusion GA‐enhanced MRI and clinical variables might assist in preoperative estimation of MVI, VETC, and MVI+/VETC+ in HCC. Evidence Level 4 Technical Efficacy Stage 2