Study of liver fat and iron deposition quantification based on magnetic resonance imaging in rats with nonalcoholic fatty liver disease

Objective: To investigate the accuracy of magnetic resonance imaging (MRI) for quantitative determination of liver fat and iron content through a rat model of non-alcoholic fatty liver disease (NAFLD) induced by methionine-choline deficient (MCD) diet. Methods: Sixty SD rats were randomly divided into experimental (MCD-diet group, n = 30) and normal control group (normal diet, n = 30). Rats were subjected to special MRI examinations at the ends of 2, 4, and 8 weeks. Proton density fat fraction (PDFF) and R2* value were obtained, and then the rats were sacrificed. The liver tissues were stained with HE, Prussian blue, etc. Liver tissue non-heme iron (NHI) homogenate was determined by flame atomic absorption spectrometry. According to different data, one-way analysis of variance, t-test or χ (2) test was used for statistical analysis. Results: PDFF and R2 * values in the MCD diet group at 2, 4 and 8 weeks were 23.37% ± 9.20%, 28.07% ± 6.84%, 25.40% ± 7.04% (P < 0.01) and 90.58 ± 15.92, 104.12 ± 13.47, 106.35 ± 15.76 (P < 0.05), respectively, which were significantly higher than the normal control group PDFF (2.39% ± 0.50%, 2.45% ± 0.45%, 3.26% ± 0.80%) and R2* (48.93 ± 7.90, 54.71 ± 5.91, 64.25 ± 15.76). Additionally, with the disease progression, R2 * had gradually increased, which was consistent with the NHI trend in liver tissue homogenates of each group. Conclusion: MRI, as a non-invasive quantitative method, can accurately assess liver fat and iron content in fatty liver disease, and with the degree of severity of fat changes, iron deposits tend to increase.