Experimental and Clinical Studies on Acute Cerebral Ischemia by Magnetic Resonance Imaging

磁共振成像在急性脑缺血的实验与临床研究对实验性和临床脑缺血急性期进行核磁共振成像（MRI）检查。采用单侧大脑中动脉闭塞致大鼠缺血模型，观察MRI时间进程和脑缺血损伤的游离水组分。所采用的MRI系统是为临床使用而设计的，永磁体在0.15特斯拉的场强下运行。用差示扫描量热法（DSC）研究了缺血性病变中游离水组分。缺血损伤后12小时的t2加权图像和t2计算图像可以显示缺血病变，缺血损伤后24小时的t1加权图像和t1计算图像可以显示缺血病变。实验脑缺血的MRI变化与临床脑缺血相似。损伤后12 ~ 24小时游离水成分显著增加，这种增加与t1加权图像上缺血的变化相似。综上所述，MRI可以在损伤后12小时的t2加权图像上检测到脑缺血，并且t1加权图像的变化与脑缺血的游离水成分相关。

Experimental and Clinical Studies on Acute Cerebral Ischemia by Magnetic Resonance ImagingNuclear magnetic resonance imaging (MRI) was performed in the acute stage of experimental and clinical cerebral ischemia. The time course of MRI, free water component of the ischemic lesion were experimentally examined in rats ischemic model induced by unilateral middle cerebral artery occulsion. The MRI system employed was designed for clinical use and the permanent magnet was operated at a field strength of 0.15 tesla. Free water component in the ischemic lesion was studied by means of differential scanning calorimetry (DSC). The ischemic lesion could be revealed on a T2-weighted image and a T2-calculated image 12 hours after ischemic insult, and on a T1-weighted image and a T1-calculated image 24 hours after ischemic insult. These changes on MRI in experimental ischemia were similar to those in clinical cases of cerebral ischemia. Free water component increased markedly from 12 to 24 hours after insult and this increase was paralleling the change of ischemia on T1-weighted images.From these results, it is concluded that MRI can detect cerebral ischemia 12 hours after insult on a T2-weighted image and the changes of a T1-weighted image are correlated with free water component of the cerebral ischemia.