中文摘要：

【摘要】目的探讨基于体素内不相干运动（IVIM）DWI技术评估对比剂急性肾损伤（CI-AKI）。肾功能动态变化的可行性。方法27只雄性SD大鼠通过尾静脉注射泛影葡胺成功制作CI-AKI模型。采用随机数字表法随机选取6只SD大鼠，分别在注射对比剂前24h及注射对比剂后30min、12h、24h、48h、72h、96h行肾脏IVIMDWI检查。测量肾皮质、内髓、外髓各参数，包括真实扩散系数（D值）、ADC值、灌注相关扩散系数（D＊值）和灌注分数（f值）。在对应MRI检查的7个时间点任意分别选取3只大鼠，处死后获取右肾标本观察病理表现。采用两个重复测量因素的方差分析法比较不同时间点MRI参数的差异，并与病理表现对照。结果注射对比剂前24h，肾皮质ADC值、D值分别为（1．74±0．06）×10^-3、（1．63±0．05）×10^-3mm2／s，注射对比剂后30min，分别降至（1．59±0．06）×10^-3、（1．58±0．06）×10^-3mm2／s，ADC值差异有统计学意义（P=0．014），D值轻度下降，差异有统计学意义（P〈0．05）。肾皮质D值、ADC值于12～48h持续下降，至72h回升；内髓及外髓D值、ADC值下降持续时间更长，至96h回升。肾皮质、内髓及外髓D＊值在注射对比剂后30min即有不同程度下降，24h达最低值，而后于48h回升；在皮质及外髓，f值下降（12h）稍晚于D。值，回升（72h）亦稍晚于D＊值。注射对比剂后不同时间的病理切片显微镜下可见不同程度的肾小球细胞、肾小管上皮细胞浊肿，萎缩甚至坏死，以及间质充血、毛细血管扩张等。结论IVIMDWI技术可有效评估对比剂急性。肾损伤肾功能动态变化过程。

英文摘要：

Objective To demonstrate that intravoxel incoherent motion （IVIM） imaging can assess temporal renal functional changes in contrast-induced acute kidney injury （CI-AKI）. Methods Twenty-seven male Sprague-Dawley （SD） rats with weight of 200 to 250 g were injected with meglumine diatrizoate （370 mg/ml, 6 ml/kg body weight） to induced CI-AKI. Six rats were randomly selected and imaged at 24 h prior to and at 30 min, 12 h, 24 h, 48 h, 72 h and 96 h after injection, and three rats were sacrificed for histological analysis at each time point. The coronal MR imaging of right kidney was analyzed. The IVIM parameters （D, D＊ and f） from regions of cortex （CO）, outer medulla （OM）, and inner medulla （IM） were obtained and compared with the pathologic findings. We used Two way repeated measures ANOVA for statistical analysis. Results At 24 h prior to the injection, the ADC value for CO was （1.74±0.06）×10^-3 mm2/ s, and then decreased to （1.59±0.06）×10^-3mm2/s at 30 rain after the injection（P=0.014）. The D value for CO was （1.63±0.05）×10^-3mm2/s, and then decreased to （1.58±0.06） ×10^-3 mm2/s at 30 min after the injection（P〈 0.05）.In the CO, a progressive reduction was observed in D and ADC from 24 h to 48 h, and a progressive increase starting from 72 h, while a later changed pattern was found in OM and IM, where D and ADC values decreased until 72 h, followed by a progressive increase starting from 96 h. D＊ decreased in CO, OM and IM early at 30 min and to the bottom at 24 h. The recovery for D＊ was found at 48 h. A significant decrease was shown for f in both the cortex and medullar in an early stage of CI-AKI （12 to 48 h） and then ascend in the later stage （72 to 96 h）, which was later than D＊ in CO and OM. The HE staining were obtained fully and serial pathological change in different degree could be seen including tubule epithelial cells and glomerulus cells cloudy swelling, atrophy, even necrosis and interstitial vasodilator. Conclusion IVI