Ultrasonographic Quantitative Estimation of Hepatic Steatosis in Children With NAFLD

Abstract

The diagnostic accuracy of hepatic ultrasonography (US) for detection and grading of hepatic steatosis in children with suspected nonalcoholic fatty liver disease (NAFLD) remains poorly characterized. The aim of this study was to prospectively evaluate the clinical utility of ultrasonographic quantification of hepatic steatosis. Our cohort consisted of 208 consecutive pediatric patients with biopsy-proven NAFLD. Hepatic US was performed within 1 month of the liver biopsy procedure. Steatosis identified by US was scored using a 0 to 3 scale based on echogenicity and visualization of vasculature, parenchyma, and diaphragm, and compared to histological features based on Brunt's classification. The median age at time of first visit was 10.8 years and 64% were boys. Sixty-nine percent had moderate to severe steatosis on histology. Ultrasonographic steatosis score (USS) had an excellent correlation with histological grade of steatosis (with a Spearman's coefficient of 0.80). The area under the receiver operating characteristic curve for ultrasonographic detection of moderate-to-severe steatosis was 0.87. The USS did not correlate significantly with inflammatory activity or fibrosis stage; however, there was significant correlation with the NAFLD activity score (NAS), albeit this was in large part the result of the strong correlation with the steatosis component of NAS. Serum alanine transaminase and aspartate transaminase were not associated with histological grade of steatosis and showed no correlation with USS. Our results, which represent the largest prospective pediatric study evaluating the role of hepatic US in children with biopsy-proven NAFLD, demonstrate the utility of this technique for noninvasive diagnosis and estimation of hepatic steatosis in children.