Feasibility of modified Dixon MRI techniques for hepatic fat quantification in hepatic disorders: validation with MRS and histology.

Objective: To assess the feasibility of proton density fat fraction (PDFF) MRI for estimating hepatic fat fraction with magnetic resonance spectroscopy (MRS) and histology as references and to investigate intrahepatic fat distribution and variability. Methods: Between November 2014 and September 2015, 85 adults (48 males, 47 females) who underwent MRI-PDFF (n = 139), MRS-PDFF (n = 49) and liver biopsy (n = 29) were enrolled in this study. Data were compared using linear regression. MRI-PDFF and standard deviations (variability) and differences between maximum and minimum PDFF (PDFF range) for whole liver, the lobes, and segment levels were calculated for each subject. Results: Whole-liver MRI-PDFF showed good correlation with MRS-PDFF (r = 0.961) and histologic degree of hepatic steatosis (sigma = 0.809). Hepatic fat fraction is different between lobes and segments. Mean PDFF and mean PDFF range of the right lobe were higher than for the left lobe, whereas variability in the right lobe was lower than in the left lobe. Conclusion: MRI-PDFF is an accurate non-invasive method for quantifying hepatic fat for various hepatic disorders, and may be preferable for measuring fat fraction in the right liver for more precise values in longitudinal monitoring, while avoiding FF measurement in the left liver. Advances in knowledge: MRI-PDFF provides a non-invasive and accurate quantification of hepatic steatosis in various hepatic disorders. It would be preferable to measure FF in the right liver than in the left liver.