MRI-derived Visceral Adipose Tissue Quantification Enhances Stratification of Nonalcoholic Steatohepatitis Severity and Fibrosis in Obesity

Purpose Visceral adiposity is a key factor in the development of nonalcoholic steatohepatitis (NASH), yet its quantitative relationship with fibrotic progression remains inadequately characterized. This study aimed to assess the diagnostic performance of MRI-derived visceral fat content (VFC) for stratifying NASH severity and fibrosis in obese individuals. Methods In this retrospective, single-center study, 138 obese patients (body mass index ≥ 30 kg/m²) who underwent liver biopsy and chemical shift–encoded MRI (IDEAL-IQ) between April 2020 and September 2022 were included. Fibrotic NASH (Fibro-NASH) was defined histologically as a NAFLD activity score (NAS) ≥ 4 and fibrosis stage ≥ 2. MRI-derived metrics, including VFC and visceral fat area (VFA), were compared between groups. Multivariable logistic regression and receiver operating characteristic (ROC) analyses were performed. Results Patients with Fibro-NASH had significantly lower median VFC compared to those without Fibro-NASH (89.3% vs. 90.4%, P  < 0.001). VFC was identified as an independent protective factor against Fibro-NASH (odds ratio (OR) = 0.51, 95% CI: 0.26–0.97). A model combining VFC, muscle fat content, and aspartate aminotransferase exhibited the highest predictive accuracy for Fibro-NASH (AUC = 0.89; 95% CI, 0.80–0.97), outperforming models using VFA and VFC alone (both P < 0.05). Conclusion MRI-derived VFC represents a robust, noninvasive biomarker for assessing NASH severity and its progression to Fibro-NASH in obesity. Integrating VFC into clinical practice may enhance risk stratification and facilitate timely interventions for advanced liver disease.