磁共振三维伪连续动脉自旋标记灌注成像评估大鼠缺血性卒中

An experimental study of 3D whole-brain pseudo-continuous arterial spin labeling MRI for assessing ischemic stroke in rats

目的：探讨磁共振三维动脉自旋标记灌注成像（3D-ASL）评估缺血性脑卒中大鼠脑血流动力学的可行性及其与扩散加权成像（DWI）的相关性。方法：对19只大鼠采用线栓法制作左侧大脑中动脉栓塞缺血模型,并于栓塞后30min、2～3h和6～7h分别行MRI扫描,测量并计算闭塞侧脑缺血部位及对侧对称区域的脑血流量（CBF）和表观扩散系数（ADC）的绝对值和相对比值,并进行统计学分析（配对t检验）;采用Pearson相关性分析评估CBF与ADC相对比值的相关性。结果：17只大鼠模型纳入数据分析。栓塞后不同时间点闭塞侧CBF及ADC值与对侧相比,差异有统计学意义（30min CBF：t=9.04,P〈0.001;30min ADC：t=18.00,P〈0.001;2～3hCBF：t=12.55,P〈0.001;2～3hADC：t=24.02,P〈0.001;6～7hCBF：t=10.32,P〈0.001;6～7hADC：t=18.38,P〈0.001）。不同时间点脑缺血部位的CBF与ADC相对值间均具有相关性（30min：r=0.665,P=0.004;2～3h：r=0.724,P=0.001;6～7h：r=0.835,P〈0.001）。结论：3D-ASL能够用于评估大鼠缺血脑组织的损伤情况,CBF与ADC值具有良好的相关性。

Objective：To evaluate the feasibility of 3D whole-brain pseudo-continuous arterial spin labeling （3D-ASL） for assessing the cerebral hemodynamics of rats with ischemic stroke and the correlation of 3D-ASL with diffusion weighted imaging （DWI）. Methods：Cerebral ischemia model of middle cerebral artery occlusion was established in 19 rats using the suture method. MRI was performed at 30min,2～3h,and 6～7h after occlusion. The cerebral blood flow （CBF） and appa rent diffusion coefficient （ADC） at the occluded side and the contralateral side,as well as relative CBF （rCBF） and relative ADC （rADC） were measured. Comparison of CBF and ADC between the occluded side and the contralateral side was made by paired t test; the correlation between rCBF and rADC was determined by Pearson correlation analysis. Results： Seventeen model rats were included in this study. There were significant differences in CBFs and ADCs between the occluded side and the contralateral side at different time points after occlusion （ 30min CBF ： t = 9.04, P〈0.001 ; 30min ADC ： t = 18.00, P〈0.001;2～3hCBF：t=12.55,P〈0.001;2～3hADC：t=24.02,P〈0.001;6～7h CBF：t=10.32,P〈0.001;6～7h ADC： t= 18.38,P〈0. 001）. There was statistically significant correlation between rCBF and rADC （30min：r--0. 665, P 0. 004; 2～ah：r=0. 724,P=0. 001;6～7h：r=0. 835,P%0. 001）. Conclusion：3D-ASL can be used to assess the ischemic brain in- jury in rats,and rCBF shows a good correlation with rADC.