Abstract
OBJECTIVE: This study aimed to investigate the reproducibility of ultrasound-derived fat fraction (UDFF) among operators with different experience levels. Furthermore, it seeks to validate the performance of UDFF in detecting hepatic steatosis. MATERIALS AND METHODS: The study was conducted at three hospitals and involved patients suspected of having metabolic dysfunction-associated steatotic liver disease (MASLD). Two radiologists took UDFF measurements from each participant to find the best place to measure and evaluate reproducibility. Subsequently, the performance of the UDFF measurements from the left and right liver lobes in detecting hepatic steatosis was compared with magnetic resonance proton density fat fraction (MRI-PDFF) results. RESULTS: A total of 163 patients were examined for UDFF in both left and right liver lobes. The measurement failure rates were 28.8% for the left lobe and 6.5% for the right lobe. The inter-observer reproducibility was high in the right lobe, with intraclass correlation coefficient (ICCs) of 0.89-0.96. Additionally, 80 participants underwent magnetic MRI-PDFF and UDFF examinations, revealing an area under the curve (AUC) of 0.97 for the right lobe and 0.84 for the left lobe. CONCLUSION: UDFF measurements in the left lobe exhibited a higher failure rate and less consistency, while measurements in the right lobe had a higher success rate and excellent reproducibility. For suspected MASLD patients, at least two measurements were recommended. Additionally, UDFF from the right lobe is more reliable for detecting fatty liver. However, the study had a small sample size, and future research should include larger, multi-center studies. CRITICAL RELEVANCE STATEMENT: Ultrasound-derived fat fraction (UDFF) represents an objective technique characterized by high stability and reproducibility that accurately assesses liver fat content, which is suitable for the screening of metabolic dysfunction-associated steatotic liver disease (MASLD). KEY POINTS: Ultrasound-derived fat fraction (UDFF) obtained from the right lobe demonstrates strong repeatability and reproducibility. UDFF has good diagnostic performance in grading steatosis. UDFF is suitable for the screening of metabolic dysfunction-associated steatotic liver disease (MASLD).