Abstract: Objective To explore the value of shear wave elastography (SWE) and ultrasound attenuation parameters (UAP) in evaluating the degree of liver steatosis in obese adolescents with non-alcoholic fatty liver disease (NAFLD). Methods 146 patients with NAFLD confirmed by liver biopsy in Jiangyou Second People's Hospital from May 2020 to September 2022 were retrospectively selected. Data were collected and liver biochemical tests including serum alanine transaminase (ALT), aspartic acid transaminase (AST), γ-glutamyltransferase (GGT), triglycerides (TG), total bilirubin (TBil), total cholesterol (TC), and low density lipoprotein (LDL) were performed to calculatethe hepatic steatosis index (HSI) . Based on the results of liver biopsy, patients were graded for liver steatosis (S0-S4), and liver stiffness (LS) and spleen stiffness (SS) were measured using a shear wave elastic imaging ultrasound diagnostic instrument. UAP was measured using a liver instantaneous elastic scanner to analyze the evaluation value of the above indicators for liver steatosis grading. Results In this study, NAFLD patients were classified by liver tissue biopsy, including 5 patients with S0 grade, 26 patients with S1 grade, 58 patients with S2 grade, and 57 patients with S3 grade. There was no statistically significant difference in gender, age, GGT, TG, TC, TBil, and LDL among patients with different liver steatosis grades (all P>0.05). The higher the patient grade, the higher the levels of BMI, ALT, AST, HSI, SWE parameters LS, SS, and UAP (F=10.1817~290.9213, all P<0.05). Spearman correlation analysis showed that LS, SS, and UAP were positively correlated with BMI, ALT, AST, and HSI levels (r=0.450~0.587, all P<0.05), but not with gender, age, etc. (all P>0.05). The overall efficacy of combined SWE parameters and UAP parameters in the diagnosis of fatty liver grade was higher than that of single SWE parameters or UAP parameters(S2: AUC=0.881, 95%CI=0.796~0.966, S3: AUC=0.887, 95%CI=0.788~0.985, all P<0.05). The Sensitivity and specificity of the combined SWE parameters and UAP parameters in the diagnosis of S2 grade fatty liver grade were 87.9% and 87.1%, respectively, and the sensitivity and specificity of the combined SWE parameters and UAP parameters in the diagnosis of S3 grade fatty liver grade were 94.7% and 87.1%, respectively. Conclusion The higher the grading of liver steatosis in obese adolescents with NAFLD, the higher the LS, SS, and UAP. SWE and UAP have high evaluation value for their grading, and their combined diagnosis can improve their diagnostic efficacy.

Key words: Shear wave elastography, Ultrasound attenuation parameters, Non-alcoholic fatty liver disease, Hepatic steatosis index, Spleen stiffness