RESUMO
OBJECTIVE: To estimate the performance of the FibroTouch-based ultrasound attenuation parameter (UAP) for assessing hepatic steatosis in nonalcoholic fatty liver disease (NAFLD), with magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard. METHODS: This prospective, cross-sectional study included 275 individuals in the training group and 110 individuals in the validation group, all of whom completed a standardized research visit, laboratory tests, MRI-PDFF, and UAP measurements over 1 month. Pearson correlation coefficient and Bland-Altman analysis were used to assess the agreement between UAP and MRI-PDFF for the detection of hepatic steatosis. The diagnostic value of UAP was evaluated by the area under the receiver operating characteristic (ROC) curve (AUROC). Confounding factors to UAP performance were identified by ROC curves and regression analyses. RESULTS: The AUROC of UAP for detecting MRI-PDFF at ≥5%, ≥10%, and ≥20% were 0.95 (95% confidence interval [CI] 0.92-0.97), 0.86 (95% CI 0.81-0.90), and 0.90 (95% CI 0.86-0.93), respectively, and their optimal thresholds were 259, 274, and 295 dB/m, respectively. The UAP measurements had higher diagnostic accuracy in participants with lower waist circumference (≤90 cm for men and ≤80 cm for women) compared to those with higher waist circumference (AUROC values: 0.97 vs 0.84, P < 0.05). Bland-Altman analysis showed good agreement between UAP and MRI-PDFF (bias 0.00021). According to established regression analyses, hepatic steatosis could be accurately diagnosed using UAP estimation. CONCLUSIONS: FibroTouch-UAP has a high diagnostic potential for hepatic steatosis in NAFLD patients and helps clinical assessment and monitoring.