Clinical Value of Ultrasound Fat Fraction in Grading Hepatic Steatosis: Preliminary Cut-Off Values in Obese Patients

Objectives: Liver steatosis is one of the main causes of liver disease with several clinical implications, such as steatohepatitis, liver cirrhosis, and hepatocellular carcinoma. It is associated with increased cardiovascular risk. Reliable, non-invasive methods to classify and evaluate improvement or worsening of liver steatosis at the diagnosis and during follow-up are therefore essential. This study aims to evaluate the accuracy of ultrasound fat fraction (USFF) in a population of patients with moderate to morbid obesity. Method: A total of 95 obese patients were evaluated for liver steatosis with ultrasound visual assessment and USFF measurement using the Samsung RS85 Prestige system. 84 patients were included (exclusion criteria were morphological features of advanced liver disease or cirrhosis, active viral hepatitis, alcohol use disorder, liver enzymes alteration and heart failure) Based on the visual assessment, patients were classified into four categories: absent, mild, moderate, and severe steatosis. The distribution of USFF values across groups was analyzed using one-way ANOVA with post-hoc comparisons. Receiver Operating Characteristic (ROC) curves were generated, and the Youden index was applied to determine optimal USFF cut-off points for each steatosis grade. Results: Mean USFF values increased progressively across the severity spectrum and significant differences in mean USFF values were observed across all four steatosis grades groups (p < 0.001). Based on the Youden index, the following cut-offs have been proposed: no steatosis USFF < 7.33, mild steatosis USFF < 11.66, moderate steatosis USFF < 16.30. Conclusions: Our findings suggest that USFF may offer a valuable tool for objectively quantifying liver fat content with a more easily comparable parameter, improving the accuracy of steatosis grading and follow-up.