增强磁共振成像评价脑缺血再灌注后大鼠血脑屏障的通透性

目的通过增强磁共振成像(MRI)来研究脑缺血再灌注后大鼠血脑屏障(BBB)通透性的改变。方法采用线栓法制备大鼠局灶性脑缺血再灌注模型。用1.5T超导型MR机进行大鼠脑冠状位扫描,随后经股静脉注入Gd-DTPA,迅速行同层间歇扫描。结果脑缺血4h,再灌注50min时,缺血侧纹状体增强率与对侧相比差别具有非常显著性意义(P<0.01)。再灌注70min时,缺血侧大脑皮层增强率较对侧增高(P<0.05)。缺血侧侧脑室在再灌注10min时可见明显强化。结论纹状体区BBB比大脑皮层更易受到再灌注损伤。血脑脊液屏障较早受到破坏。增强MRI是一种敏感的在活体条件下检测BBB损伤的理想方法。

Evaluation of blood brain barrier permeability during reperfusion following focal cerebral ischemia in rats using contrast enhanced MRI

Objective Contrast enhanced MRI was used to observe blood brain barrier(BBB) permeability during reperfusion following middle cerebral arteries occlusion (MCAO) in rats.Method The left middle cerebral arteries were transiently occluded by inserting a nylon thread into the carotid artery.T2 W and T1 W images were obtained in a 1.5 T magnet before and after Gd DTPA was injected intravenously. The percent enhancement of signal intensity (SI) was calculated.Result Enhancement of the striatum was seen following 50 min reperfusion,and enhancement of the cerebral cortex was evident following 70 min reperfusion in the affected hemisphere.The lateral ventricle of the ischemic hemisphere showed enhancement following 10 min reperfusion .Conclusion BBB damage had a stronger tendency to occur in the striatum than in the cerebral cortex.Disruption of the blood CSF barrier happened easily. MR enhancement is proposed as a sensitive method for quantification of BBB injury in vivo.