Abstract: Objective The aim of this study was to investigate diagnostic performance of ultrasound attenuation coefficient (AC) and serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) ratio in evaluating liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD). Methods 70 patients with NAFLD and 30 volunteers for healthy physical examination were admitted to our hospital between May 2021 and May 2024, and all patients with NAFLD received liver biopsies. Ultrasonic attenuation imaging (ATI) was performed to measure AC, and serum ALT and AST levels were routinely detected. Receiver operating characteristic (ROC) curves were applied to analyze predicting efficacy of AC and serum ALT/AST ratio combination for liver steatosis in patients with NAFLD. Results Of 70 patients with NAFLD in our series, liver histo-pathological examination showed liver steatosis of mild degree in 20 cases, moderate in 28 cases and severe in 22 cases; AC in patients with severe liver steatosis was (1.1±0.4)dB·cm^-1·MHz^-1, much higher than [(0.8±0.3)dB·cm^-1·MHz^-1, P＜0.05] in moderate or [(0.6±0.2)dB·cm^-1·MHz^-1, P<0.05] in mild and [(0.5±0.1)dB·cm^-1·MHz^-1, P＜0.05] in healthy persons, and serum ALT/AST ratio was (1.0±0.1), much lower than [(1.3±0.2), P＜0.05] in moderate or [(1.7±0.4), P＜0.05] in mild and [(1.8±0.5), P＜0.05] in healthy control; ROC analysis showed that the AUC was 0.882(95%CI:0.745-0.961), with sensitivity (Se) of 92.9% and specificity (Sp) of 75.0%, when AC and ALT/AST ratio combination in predicting moderate liver steatosis (P＜0.05), and the AUC was 0.902(95%CI:0.804-0.978), with Se of 95.5% and Sp of 85.0%, when the two parameters combined in predicting severe liver steatosis, much superior to any parameter doing alone (P＜0.05). Conclusion Combination of AC and serum ALT/AST ratio might help clinicians for early liver steatosis screening, which needs further clinical investigation.

Key words: Nonalcoholic fatty liver disease, Liver steatosis, Ultrasound attenuation coefficient, Serum alanine aminotransferase/aspartate aminotransferase ratio, Diagnosis