大鼠局灶性脑梗塞的MRI及近红外光谱的动态变化研究

在大鼠实验性脑梗塞模型上，应用ＭＲＩ灰阶定量以及近红外光谱方法探讨脑梗塞早期诊断的可能性。方法：用尼龙丝插入大鼠一侧颈内动脉造成局灶性脑梗塞，再用Ｔ２加权的ＭＲＩ影像进行灰阶定量测定以及ＨａｍａｍａｔｓｕＮＩＲＯ－５００型近红外光谱仪观测脑血氧代谢的动态变化过程。结果：在缺血３０分钟后，用近红外光谱仪已可测出脑缺血侧的氧合血红蛋白和总血红蛋白量显著降低，还原型血红蛋白增加；在Ｔ２加权的ＭＲＩ影像灰阶定量研究中，缺血２０分钟后缺血区已可见灰阶轻度增强，缺血２小时后，缺血区的Ｔ２加权灰阶值较对照区增加５．５６％，缺血２０小时后，灰阶值较对照侧增加３７．８％。动物实验结果表明，用近红外光谱检测方法结合ＭＲＩ的Ｔ２加权灰阶定量，有可能对脑梗塞作出较早期的诊断。

Study on Dynamic Changes of MRI and NIRS on Focal Cerebral Infarction in Rats

To investigate the possibility of early diagnosis of the cerebral infarction using MRI and near infra red spectrography (NIRS) in the animal models of the cerebral infarction. Nyron thread was inserted into the internal carotid artery in rats to establish an animal model of cerebral infarction. The T 2 weighting MRI images were studied and the Hamamatsu NIRO-500 spectroscope was used to investigate the dynamic changes of the cerebral oxygen metabolism. Results: After occlusion of the middle cerebral artery for 30 mimutes, the content of Hbo2 and HbT decreased while that of Hb increased significantly. In T 2 weighting MRI images, the gray grade of the ischemic foci moderately in creased as compared to the normal tissue after 20 min ischemia. During a period of ischemia for 2 hours, the gray grade values in the ischemic area increased about 5.56% and after 20 hour ischemia the gray grade values of the ischemic area significantly increased to 37. 8%.According to our preliminary results it was suggested that NIRS combined with the MRI quantitation may be of certain value for the early diagnosis of the clinical cerebral infarction.