This prospective study, conducted at two centers, assessed the diagnostic efficacy of ultrasound-derived fat fraction (UDFF) for evaluating hepatic steatosis. The results indicate that UDFF is an accurate and convenient non-invasive tool for evaluating varying degrees of hepatic steatosis. Compared to traditional non-invasive blood tests such as HSI, FLI, and CAPS, as well as visual scoring, UDFF demonstrated superior diagnostic accuracy. The significant correlation between UDFF and MRI-PDFF (r = 0.84, p < 0.001) validates UDFF as a dependable indicator of liver fat content, consistent with previous studies (21, 22).
UDFF exhibited higher diagnostic accuracy than serum biomarkers like FLI, HSI, and CAPS, aligning with trends from past research (23, 24). For instance, Tavaglione et al. (23) found that while serum markers can indirectly reflect liver fat content, imaging tools typically provide more direct and precise results. Compared to MRI-PDFF, the gold standard for quantitative imaging, UDFF offers greater accessibility, ease of use, and lower costs, making it ideal for resource-limited healthcare settings and enabling large-scale screening and long-term monitoring (25).
Furthermore, UDFF can be operated using existing ultrasound equipment without significant additional investment, greatly enhancing its application prospects in routine clinical practice, especially for preliminary screening and long-term monitoring. Unlike liver biopsy, UDFF offers a non-invasive and convenient assessment tool for individuals at high risk for MASLD (26).
Importantly, this study also provides optimal cutoff values for different stages of hepatic steatosis. These findings align with those of Kubale et al. (14), who reported diagnostic thresholds of 6.5% for S1, 17.4% for S2, and 22.1% for S3. While these thresholds offer valuable references for clinical practice, our study indicated that UDFF may show a slight positive bias in certain cases compared to MRI-PDFF. The mean bias for UDFF was 2.06%, with 95% limits of agreement between − 7.03% and 11.15%. This trend has been noted in previous studies as well (13, 27), suggesting that UDFF may face some systematic bias in clinical applications. Future studies should aim to enhance imaging parameters, establish uniform measurement protocols, and account for population-specific characteristics (28).
This study also has certain limitations. Although the sample size adequately supports our findings, further validation of UDFF's performance is necessary across diverse ethnic groups and MASLD patient populations. Secondly, the study did not employ liver biopsy as a reference standard. Although MRI-PDFF is widely regarded as an alternative for quantitative liver fat assessment, its correlation with histology requires further validation. Lastly, the application of UDFF in long-term clinical outcomes, such as monitoring treatment responses and disease progression, requires more longitudinal studies for support.
In conclusion, this study provides strong support for UDFF as a non-invasive, cost-effective, and accurate tool for assessing hepatic steatosis. Additional studies are needed to enhance the application of UDFF in diverse clinical settings.