Ultrasonographic fatty liver indicator detects mild steatosis and correlates with metabolic/histological parameters in various liver diseases

Background and aims Fatty liver is a common feature of different types of liver diseases. The sensitivity and specificity of ultrasonography for diagnosing fatty liver are variable. A semi-quantitative ultrasound score, i.e., the ultrasonographic fatty liver indicator (US-FLI), is closely associated with metabolic/histological variables in patients with nonalcoholic fatty liver disease (NAFLD). The main aims of this study were to assess the diagnostic performance of US-FLI in detecting varying degrees of histological steatosis, and to examine the association of US-FLI with metabolic/histological parameters in 352 biopsied patients with various chronic liver diseases (173 with hepatitis C [HCV], 23 with hepatitis B [HBV], 123 with NAFLD and 33 with other etiologies). Results US-FLI accurately detected mild steatosis (minimum amount 10% on histology) with a cut-off value ≥ 2 (sensitivity 90.1%, specificity 90%), moderate steatosis (≥ 30%) with a cut-off value ≥ 3 (sensitivity 86.4%, specificity 92.5%) and severe steatosis (> 66%) with a cut-off value ≥ 5 (sensitivity 88.5%, specificity 87%). US-FLI was correlated with steatosis percentage in each liver disease group as well as with lobular inflammation, ballooning, portal fibrosis, grading and staging in patients with NAFLD or HCV. US-FLI was also correlated with waist circumference, body mass index and insulin resistance both in the whole sample and in each liver disease group. Conclusions US-FLI accurately identifies histological severity and is correlated with metabolic parameters in patients with various steatogenic liver diseases. US-FLI is an easy and versatile tool for the screening of steatosis and the metabolic health of these patients.