Purpose: The aim of this study was to examine whether abdominal ultrasonography (US) could be used to diagnose fatty liver, hepatic fibrosis, and hepatic tumors in nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver disease (NAFLD) model mice, obviating unnecessary autopsies and increasing the efficiency of research.
Methods: Thirty-eight, 19-week-old, male C57BL/6J mice were used to produce NASH and NAFLD group mice and a control group. US was performed on Day 120, and the mice were then autopsied for histopathological examination and to identify hepatic tumors. Relationships of hepatorenal echo contrast (HEC) and the heterogeneity of liver parenchyma (HOLP) on US with histopathological findings were evaluated.
Results: Histopathological examination confirmed fatty degeneration and hepatic fibrosis in the NAFLD and NASH groups, as did US. The correlation coefficient of the HEC ratio and the fat deposition area showed a significant correlation (0.7295, p < 0.01); the HOLP index showed no correlation with the fat deposition area. Sixteen hepatic tumors were confirmed on autopsy, all in the NASH group, in 9 of 15 mice; of the 16 tumors, 13 (81.2%) were seen on abdominal US. The mean diameter of the tumors imaged was 2.2 ± 0.7 mm, and the mean diameter of the tumors not imaged was 2.9 ± 0.9 mm, with no significant difference (p = 0.2017). The tumors that were not imaged were on the liver periphery or protruding outside the liver from the posterior surface.
Conclusion: This study shows that US can confirm the extent of hepatic fatty degeneration and tumor formation in NASH model mice without autopsy.
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