3.0 T fMRI评价大鼠对比剂急性肾损害与病理对照研究

Evaluation of contrast-induced acute renal injury and pathology in rats by 3.0 T fMRI：A comparative study

目的 应用3.0 T磁共振功能成像技术（BOLD及ASL-fMRI）评估大鼠对比剂急性肾损害（CI-AKI）与病理损伤对照.方法 将30只雄性SD大鼠随机分为注射对比剂前对照组和注射对比剂后20 min、24 h、48 h、72 h和7 d注射组,并且于注射对比剂前、注射对比剂后20 min、24 h、48 h、72 h和7 d共6个时间点行3.0 T BOLD及ASL-fMRI扫描,测量大鼠肾脏外髓部R2＊值和血流量（RBF）值,取大鼠肾脏HE染色后评价外髓部肾小管损伤情况,分析和比较两组大鼠肾脏R2＊值和RBF值以及病理损伤变化.结果 与注射对比剂前比较,大鼠肾脏注射对比剂20 min后R2＊值升高,持续至72 h,7 d后回落至等于注射对比剂前;注射对比剂20 min后RBF值升高,持续至48 h,72 h后回落至低于注射对比剂前,直至7 d组;大鼠注射对比剂后20 min肾脏外髓部肾小管即出现损伤,24 h至48 h损伤减轻,72 h损伤又加重,但低于20 min,7 d后损伤加重,与20 min组相仿.肾脏外髓部R2＊值和RBF值与病理上肾小管损伤程度评分趋势一致,获得很好的一致性结果.结论 3.0 T fMRI技术可以评估CI-AKI引起的肾血氧分压和血流灌注水平,在一定程度上反映大鼠CI-AKI肾脏损害的病理损伤机制.

Objective To evaluate and compare the contrast-induced acute kidney injury （CI-AKI） and pathological damage in rats by 3.0 T magnetic resonance imaging （BOLD and ASL-fMRI）. Methods Thirty male SD rats were randomly divided into the control group （at the baseline） and the injection groups（at 20 min,24 h,48 h,72 h and 7 days after the injection of contrast agent）. All rats were scanned by 3.0 TBOLD and ASL-fMRI at the baseline,20 min,24 h,48 h,72 h and 7 days after the injection of contrast agent. The values of R2＊ and renal blood flow（RBF）in therenal outer medulla were measured. The renal tubular injury was evaluated after HE staining of the rat kiney. The changes of R2＊and RBF values and the pathological changes were evaluated and compared between the two groups. Results The R2＊value in the rat kidney increased at 20 min after the injection of contrast agent compared with that at the baseline,and continued to 72 h,and dropped at 7 d,which was equal to that at the baseline. The RBF value increased at 20 min after the injection of contrast agent,and continued to 48 h,and dropped at 72 h, which was lower thanthat at the baseline,until 7 d. The injury of the renal tubules at the renal outer medulla was examined at 20 min after injection of the contrast agent,which was alleviated at 24 h to 48 h, aggravatedat 72 h（better than that at 20 min）,and aggravated again at 7 d（similar to that at 20 min）. The values of R2＊and RBF in the renal outer medulla were consistent with the pathologic grading of renal tubular injury,with consistent findings. Conclusion 3.0 T fMRI technique can evaluate the renal blood oxygen pressure and blood perfusion levels induced by CI-AKI,and to a certain extent reflect the pathological damage mechanism of CI-AKI renal injury in rats.