Purpose: Hepatic steatosis is a hallmark of metabolic dysfunction-associated steatotic liver disease, and increased hepatic fat (or steatosis) is associated with liver inflammation, fibrosis, and adverse outcomes. While MRI-derived proton density fat fraction (MRI-PDFF) is an accurate noninvasive reference standard, ultrasound attenuation imaging (UAI) offers an accessible cost-effective alternative. We herein systematically review and meta-analyze the accuracy of UAI in grading hepatic steatosis.

Methods: We searched Embase, PubMed/Medline, Scopus, and Web of Science through December 22, 2024, for studies comparing UAI with MRI-PDFF. Data on diagnostic performance were extracted from eligible studies. Pooled diagnostic odds ratios (DOR), sensitivity, specificity, likelihood ratios, and areas under the curve (AUCs) were calculated using random-effects models, with heterogeneity assessed through I².

Results: Twelve studies with a total of 3344 patients were included. For differentiating grade 0 from grade ≥ 1 steatosis, the pooled AUC was 0.82 (95% CI 0.78-0.85) and DOR was 21.10 (I² = 67.2%), with sensitivity and specificity of 83%. For differentiating grades ≤ 1 from grade ≥ 2, the AUC was 0.80 (95% CI 0.73-0.86), DOR 19.87 (I² = 89%), sensitivity 84%, and specificity 80%. For differentiating grades ≤ 2 from grade 3, the AUC was 0.78 (95% CI 0.66-0.87), DOR 19.21 (I² = 85.3%), sensitivity 86%, and specificity 80%.

Conclusion: UAI exhibits good diagnostic accuracy for grading hepatic steatosis and offers a practical, noninvasive alternative to MRI-PDFF, being particularly well-suited for screening and patient follow-up. Standardized protocols and further multicenter studies are needed to promote its clinical application.