Volumetric Liver Fat Fraction Determines Grade of Steatosis More Accurately Than Controlled Attenuation Parameter in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS: HepaFat-Scan is a magnetic resonance imaging-based method for quantification of hepatic steatosis by volumetric liver fat fraction (VLFF) measurement. We aimed to validate VLFF and to compare it with controlled attenuation parameter (CAP) for determination of hepatic steatosis grade in patients with NAFLD, using histopathology and stereologic analyses of biopsies as the reference standard. METHODS: We performed a prospective study of consecutive adults with NAFLD who were scheduled for a liver biopsy at a tertiary hospital in Malaysia. Patients underwent VLFF and CAP measurements on the same day as their liver biopsy. Histopathology analyses of liver biopsy specimens were reported according to the Nonalcoholic Steatohepatitis Clinical Research Network scoring system. Stereologic analysis was performed using grid-point counting method combined with the Delesse principle. RESULTS: We analyzed data from 97 patients (mean age 57.0 +/- 10.1 years; 44.33% male; 91.8% obese; 95.9% centrally obese). Based on histopathology analysis, the area under receiver operating characteristic curve (AUROC) for VLFF in detection of steatosis grade >= S2 was 0.92 and for CAP the AUROC was 0.65 (P<.001). Based on stereological analysis, the AUROC for VLFF for detection of steatosis grade >= S2 was 0.92 and for CAP the AUROC was 0.63, (P=.002); for identification of steatosis grade S3, the AUROC for VLFF was 0.92 and for CAP the AUROC was 0.68 (P<.001). CONCLUSIONS: In a prospective study of patients with NAFLD undergoing liver biopsy analysis, we found VLFF to more accurately determine grade of hepatic steatosis than CAP.