Dual Imaging Biomarkers for MASLD Assessment in Bariatric Patients After Sleeve Gastrectomy

Background and Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent chronic liver disease and frequently improves after bariatric surgery. Conventional postoperative follow-up is mainly based on weight-loss outcomes, such as Body Mass Index (BMI), excess weight loss (EWL), total weight loss (TWL), and routine biochemical parameters, which may not fully characterize hepatic fat response. Ultrasound-derived fat fraction (UDFF) provides a quantitative non-invasive assessment of hepatic steatosis, while DXA-derived visceral adipose tissue (VAT) reflects central adiposity and metabolic risk. This study aimed to evaluate whether combined UDFF and DXA-VAT assessment provides complementary information to conventional bariatric follow-up parameters after bariatric surgery. Methods: We conducted a prospective longitudinal cohort study on 41 patients with severe obesity who underwent bariatric surgery between July 2025 and May 2026. Anthropometric, body composition, metabolic, hepatic, and biochemical parameters were assessed at baseline (T0) and 6 months postoperatively (T1). UDFF, utilizing a DAX ultrasound transducer, was used for hepatic steatosis assessment, while DXA was performed for VAT, android fat mass, total body fat percentage, and lean mass quantification. Correlation analyses, multivariable linear regression, and an exploratory clinical discordance analysis were performed. Results: At 6 months after surgery, patients showed significant improvements in body weight, visceral adiposity, insulin resistance, biochemical parameters, and hepatic steatosis. VAT reduction showed the strongest association with UDFF reduction, whereas conventional weight-loss outcomes, anthropometric, and metabolic parameters did not fully identify patients with residual steatosis. These findings suggest that hepatic fat improvement after bariatric surgery is more closely related to changes in visceral adiposity than to weight loss alone. Conclusions: Combined UDFF and DXA-derived VAT assessment may provide a practical dual-compartment imaging framework for postoperative MASLD monitoring. This approach captures both hepatic fat response and visceral adiposity remodeling, offering information that complements conventional bariatric follow-up based on weight-loss outcomes.