Lifestyle Modification Leads to Spatially Variable Reduction in Hepatic Steatosis in Potential Living Liver Donors

The spatial variability of hepatic fat reduction in potential living liver donors with hepatic steatosis (HS) who undergo lifestyle modification has not been investigated. Here, we aimed to examine the intrasegmental and intersegmental variability of changes in liver attenuation on computed tomography (CT) in potential living liver donors with HS after diet modification and exercise. A total of 87 living liver donor candidates (30.5 ± 7.0 years; 74 males) with biopsy-proven macrovesicular fat (MaF) ≥10% were included. All underwent diet modification and exercise to improve HS, baseline and follow-up unenhanced CT scans, and liver biopsies. Attenuation and its variability (mean and standard deviation, respectively, in Hounsfield units) in segmental, lobar, superficial, deep, and whole areas of the liver were measured across 32 different regions of interest on both baseline and follow-up CT. At baseline, the right lobe and superficial areas of liver showed significantly lower and more variable attenuation than left lobe and deep areas. Greater variability was noted in patients with more severe HS. Mean interval changes in liver attenuation and variability before and after diet modification and exercise were 13.7 (range, -10.6 to 46.2) and 4.7 (1.6-10.6), respectively. The mean interval change in liver attenuation was significantly higher in the right lobe than in the left (14.7 versus 12.7; P < 0.001), and in superficial areas than in deep areas (14.0 versus 13.4; P = 0.02). Greater variability and larger interval changes in liver attenuation were noted in those who responded (≥20% decrease in MaF) to diet modification and exercise than in those who did not. In conclusion, potential living liver donors with HS show significant intrasegmental and intersegmental variability in hepatic fat reduction on CT before and after diet modification and exercise.