A Practical Approach to Quantitative Grayscale Ultrasound Analysis of Hepatic Steatosis in Pediatric Patients Using a Picture Archiving and Communication System-Based Tool.

OBJECTIVES: To evaluate the efficacy of a picture archiving and communication system (PACS)-based ultrasound (US) quantification technique for diagnosis of hepatic steatosis in a pediatric population.

METHODS: Abdominal US images of 49 pediatric patients (≤18 years) with histopathologically proven diagnoses of hepatic steatosis (n = 17), nonsteatotic liver disease (n = 19), and a normal liver (n = 13) were retrospectively reviewed. Patient demographics, the fibrosis stage, and the steatosis grade were obtained from the database. Quantitative grayscale measurements of the echo intensity level of the liver and kidneys were performed on the US images using the PACS measuring tool. The hepatorenal ratio was obtained by dividing mean liver by mean kidney values. The heterogeneity index for the liver was calculated by dividing the liver standard deviation by mean liver values. Hepatorenal ratio and heterogeneity index values of the 3 groups were correlated with pathologic results and compared by a 1-way analysis of variance. A receiver operating characteristic curve analysis was performed, and cutoff values were determined.

RESULTS: The hepatorenal ratio of the hepatic steatosis group was significantly greater than those of the control and nonsteatotic liver disease groups (P < .001). The heterogeneity index of the hepatic steatosis group was significantly greater than that of the control group (P = .046). For a hepatorenal ratio cutoff value of 1.5, 88.2% sensitivity, 91.4% specificity, 88.3% positive predictive value, and 94.1% negative predictive value were obtained for predicting hepatic steatosis.

CONCLUSIONS: PACS-based quantitative grayscale US quantification is a safe, accurate, and easily applicable objective method for the diagnosis of hepatic steatosis in children. A hepatorenal ratio of greater than 1.5 can be used as a conservative parameter, permitting increased confidence in discriminating hepatic steatosis from other conditions.