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.
目的： 通过蛋氨酸和胆碱缺乏（MCD）饮食诱导的大鼠非酒精性脂肪性肝病（NAFLD）模型探讨磁共振成像（MRI）对肝脏脂肪含量以及铁含量定量测定的准确性。 方法： 将60只SD大鼠随机分为实验组（MCD饮食，n = 30）和正常对照组（普通饮食，n = 30）。分别在2、4、8周末行大鼠专用MRI检查，获得质子密度脂肪分数（PDFF）以及R2*值后处死大鼠，取肝脏组织进行HE染色、普鲁士蓝染色等，火焰原子吸收法测定肝组织匀浆中的非血红素铁（NHI）。据资料不同用ANOVA单因素方差分析、t检验或χ(2)检验进行统计学分析。 结果： MCD饮食组在2、4、8周的PDFF值（%）分别为23.37±9.20、28.07±6.84、25.40±7.04（P < 0.01）及R2*值分别为90.58±15.92、104.12±13.47、106.35±15.76（P < 0.05），显著高于正常对照组PDFF（2.39±0.50、2.45±0.45、3.26±0.80）以及R2*（48.93±7.90、54.71±5.91、64.25±15.76），且随着疾病进展，R2*逐渐增高，与各组肝组织匀浆中的NHI趋势一致。 结论： MRI作为一种无创性量化手段，可准确评估脂肪性肝病肝脏脂肪和铁的含量，且随着脂肪变严重程度的进展，铁沉积呈加重趋势。.
Keywords: Iron deposition; Magnetic resonance imaging; Nonalcoholic fatty liver disease.