To evaluate the value of ultrasound-guided attenuation parameter (UGAP) for evaluating the degree of metabolic dysfunction-associated fatty liver disease (MAFLD) in children.

One hundred and thirty-one children in which obesity was confirmed at Shenzhen Children's Hospital between May 2022 and February 2023 were retrospectively selected. According to the ultrasound findings, the patients were divided into two groups: MAFLD group (n=76) and simple obesity group (n=55). Fifty-eight sex- and age-matched healthy children were selected as a control group. The attenuation coefficient (AC) was compared among all groups and different hepatic steatosis grades. Correlation ratio (Eta²) and Spearman's correlation coefficient were used to assess the correlation between AC and the grade of hepatic steatosis, body mass index (BMI), fibrosis-4 (FIB-4) index, and laboratory indices. Multivariate logistic regression analysis was used to construct an MAFLD predictive model. The diagnostic performance of the predictive model was evaluated by receiver operating characteristic (ROC) curve analysis.

AC values in the MAFLD, simple obesity, and normal control groups were (0.758±0.076), (0.637±0.039), and 0.575 (0.560, 0.590) dB/cm/MHz, respectively. AC values in the patients with mild, moderate, and severe fatty liver were (0.728±0.067), (0.789±0.070), and (0.858±0.041) dB/cm/MHz, respectively. There were significant differences in AC values among different groups and hepatic steatosis grades ( P<0.05 for all). There was a highly significant correlation between AC values and hepatic steatosis grades (Eta²=0.586); a moderate correlation between AC values and BMI (r_s=0.422, P<0.001); but no correlation between AC values and FIB-4 index (r_s=-0.080, P=0.58). The equation of the MAFLD predictive model was: Logistic (P) = -22.081+0.242X (100AC)+0.233X (BMI). The area under the curve of the predictive model was 0.869. The cut-off values were AC ≥ 0.675 dB/cm/MHz and BMI ≥ 22.05 kg/m².

AC values in the liver increase in children with simple obesity and those with MAFLD, which could reflect the grade of hepatic steatosis. AC values quantified using UGAP and BMI are predictors of MAFLD in children with obesity. UGAP might be an effective tool for clinical screening, diagnosis, and evaluation of hepatic steatosis severity and monitoring its progression.