Correlation Between Liver-to-Spleen Hounsfield Unit Ratio and Metabolic Improvement in Patients With Bariatric Surgery

Purpose: Non-alcoholic fatty liver disease (NAFLD) is becoming increasingly common, especially among obese individuals. This study evaluated the liver/spleen Hounsfield unit (HU) ratio (L/S ratio) as an indicator of steatosis and related metabolic diseases using contrast-enhanced computed tomography (CT). Materials and Methods: A retrospective analysis was conducted on 34 patients who underwent bariatric surgery at Eunpyeong St. Mary's Hospital between March 2019 and July 2023. All patients underwent CT scans before and 6 months after surgery. The L/S ratio was calculated by dividing the average value of 3 HU of the liver by that of the spleen. The ratio correlated with pre- and post-surgery weight changes, comorbidities, and laboratory findings. Results: The mean preoperative body mass index (BMI) was 40.5. Post-surgery, BMI significantly decreased to 31.5, and the number of patients with diabetes reduced from 18 (52.9%) to 4 (11.8%). Significant reductions were observed in hemoglobin A1c (HbA1c), aspartate transaminase (AST), and alanine transaminase (ALT) levels after surgery. The L/S ratio increased from 0.7±0.2 to 0.9±0.1, correlating with liver function improvements and weight loss (all with P<0.001). Patients with a larger change in L/S ratio demonstrated more significant improvements in AST, ALT, and HbA1c levels and a higher total weight loss percentage. Conclusion: This study demonstrated a strong correlation between changes in the L/S ratio and metabolic improvements, including diabetes remission, following bariatric surgery. The L/S ratio could serve as a valuable index for assessing NAFLD severity and monitoring the outcomes in patients undergoing bariatric surgery.