CT灌注成像联合醋甲唑胺负荷观察自发性高血压大鼠脑血管储备功能

CT perfusion imaging after administration of methazolamide for observation on cerebrovascular capacity of spontaneous hypertensive rats

目的探讨CT灌注成像(CTPI)结合醋甲唑胺负荷试验对评价自发性高血压大鼠(SHR)脑血管储备功能变化的价值。方法取10只大鼠建立SHR模型(SHR组),另取10只作为正常对照组,对两组大鼠于醋甲唑胺灌胃前后行脑CTPI,分别测量负荷前后ROI脑血容量(CBV)、脑血流量(CBF)、平均通过时间(MTT)及达峰时间(TTP);光镜下观察大鼠脑小动脉管壁厚度、微循环毛细血管网情况,通过TTC染色明确各组大鼠脑组织有无脑梗死灶。结果 CTPI显示,组内比较,静息状态与负荷状态下两组4个灌注参数值间差异均有统计学意义(P均<0.05),且负荷状态下CBV、CBF值增加,MTT、TTP值缩短。组间比较,静息状态下,两组间仅TTP值差异有统计学意义(P<0.05),负荷状态下,两组MTT、TTP值差异有统计学意义(P<0.05),且负荷状态下MTT值改变更显著。病理:两组小动脉管壁厚度差异无统计学意义(P>0.05),而微循环网毛细血管数差异统计学意义(P<0.05),SHR组微循环网毛细血管数增加;SHR组脑组织无明确脑梗死灶。结论 CTPI结合醋甲唑胺负荷试验可反映SHR脑血管储备功能改变。

Objective To assess application value of CT perfusion imaging （CTPI） combined with methazolamide stress test in observation of cerebrovascular reserve capacity changes in spontaneous hypertensive rats （SHR）. Methods Totally 20 rats including 10 in SHR group and 10 in normal control group underwent cerebral CTPI before and after intragastric administration of methazolamide. Cerebral blood volume （CBV）, cerebral blood flow （CBF）, mean transit time （MTT） and time to peak （TTP） values of ROI were measured before and after methazolamide stress test. The arteriolar wall thickness and microcirculation capillary network were observed under light microscope after HE staining of paraffin section, and cerebral infarction in brain was analyzed using TTC staining. Results CTPI showed that there were statistical differences of four perfusion parameters between resting state and load state in two groups （all P〈0.05）. CBV and CBF increased, while MTT and TTP shortened in the load state. TTP were statistical different between two groups in the resting state （P〈 0.05）. MTT and TTP had statistical differences between two groups in the load state （P〈0. 05）, and MTT changed more significantly. The arteriolar wall thickness had no statistical difference between the two groups （P〉0.05）, but there were statistical differences in microcirculation capillary network number （P〈0.05）, and the number of microcirculation capillary network of SHR relatively increased. The brain tissue of SHR had no cerebral infarction. Conclusion CTPI combined with methazolamide stress test can reflect the changes of cerebrovascular reserve of spontaneous hypertensive rats.