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背景:多数学者认为广义的缺血半暗带位于严重缺血区周围的低灌注区,处于动态变化过程,能否成功挽救半暗带成为正常灌注区,是治疗过程中的关键。磁共振能够观察脑缺血的面积,但其数据不能直观地反映缺血时间和脑梗死面积之间的变化规律。目的:观察数学模型在大鼠脑缺血-再灌注模型缺血半暗带磁共振成像中的应用效果。方法:制作大鼠大脑中动脉闭塞缺血模型,分为永久缺血组和神经保护剂组,神经保护剂组于造模成功后经鼠尾静脉注射临床常规神经保护剂灯盏花素注射液。在0.5~48h内行弥散加权成像检查,测定缺血灶不同部位的表观弥散系数,计算病侧与对侧正常组织的相对值,即相对表观弥散系数。应用最小二乘法进行数据处理,得出缺血时间和梗死面积的函数关系式,并进行线性分析。结果与结论:大鼠脑缺血-再灌注模型即相对表观弥散系数在永久缺血组9~21h时段3,4点时间(X)和相对表观弥散系数值(Y)呈负相关,且两者线性关系显著,回归方程分别为y=1.458153-0.042770333x,y=1.510346-0.037141333x。在1~6h时间段均有r>0,P<0.05,故变量X与Y呈正相关,且线性关系显著。从24~48h,1,2,3,4点的相对表观弥散系数值均随时间增加而增加。提示1~6h时间段是缺血再灌注鼠脑模型神经保护的关键时期。
BACKGROUND: Most scholars believe that the generalized ischemic penumbra is located in the hypoperfusion area around the severe ischemic area and is in a dynamic process. Whether it can successfully save the penumbra and become a normal perfusion area is the key point in the course of treatment. Magnetic resonance imaging can observe the area of cerebral ischemia, but its data can not directly reflect the changing rules between ischemic time and cerebral infarction area. Objective: To observe the effect of mathematical model in ischemic penumbra magnetic resonance imaging of cerebral ischemia-reperfusion model in rats. Methods: The model of middle cerebral artery occlusion (MCAO) in rats was made and divided into permanent ischemic group and neuroprotective agent group. The neuroprotective agent group was injected with breviscapine injection, a conventional neuroprotective agent, through tail vein of rat after successful modeling. Diffusion-weighted imaging was performed within 0.5-48 hours. Apparent diffusion coefficient of different parts of ischemic lesions was measured, and relative apparent diffusion coefficient was calculated between normal and contralateral tissues. The least squares method was used to process the data, and the functional relation between ischemic time and infarct size was obtained and analyzed linearly. RESULTS AND CONCLUSION: The relative apparent diffusion coefficient of cerebral ischemia-reperfusion model in rats was negatively correlated with the relative apparent diffusion coefficient (Y) at 3, 4, and 9 hours (P < And the linear relationship between the two was significant. The regression equations were y = 1.458153-0.042770333x, y = 1.510346-0.037141333x, respectively. There was a positive correlation between the variables X and Y and the linear relationship was significant at r = 0, P <0.05 at 1 ~ 6h. From 24 to 48h, the values of relative apparent diffusion coefficients increased with the increase of time. Tip 1 ~ 6h time period is a critical period of neuroprotection in cerebral ischemia-reperfusion model rats.