Early regression of hepatic steatosis after bariatric surgery assessed by ultrasound including attenuation imaging

Abstract Background Metabolic dysfunction-associated steatotic liver disease (MASLD) is associated with increased liver-related morbidity. Bariatric surgery provides substantial weight loss and metabolic improvement, yet data on ultrasound (US)-based monitoring remain limited. This study evaluated perioperative changes in hepatic steatosis using semiquantitative B-mode US and Attenuation Imaging (ATI), a quantitative US technique for fat quantification. Methods In this prospective single-center study, patients undergoing bariatric surgery between February 2024 and July 2025 were included. B-mode US and ATI were performed preoperatively and at 3 and/or 6 months postoperatively. For overall analysis, the earliest available postoperative examination was defined as the early follow-up. Hepatic steatosis was assessed using B-mode US grading (S0–S3) and ATI grading (aS0–aS3). Body mass index (BMI), liver size, and attenuation coefficient (AC) values were recorded. Results 89 patients were included (mean age 42.8 years; 72% female). US examinations were performed at 3 months in 75.2% of patients and at 6 months in 51.7%. Of all patients, 26.9% attended both follow-up visits. At baseline, B-mode and ATI were strongly correlated (τ_b = 0.73, p < 0.001). At early follow-up, BMI decreased in all patients ( p < 0.001). Grading of hepatic steatosis improved in 56.2% of patients by B-mode ( p < 0.001) and in 68.5% by ATI ( p < 0.001), while absolute ATI values decreased in 94.4%. Liver size decreased in 94.4%. In patients with both follow-up visits, largest reductions in ATI and liver size were observed at 3 months. Changes in B-mode and ATI grading were strongly correlated (τ_c = 0.65, p < 0.001). Conclusions Regression of hepatic steatosis occurs early after bariatric surgery. ATI complements B-mode US by providing quantitative longitudinal assessment.