CT灌注负荷试验评价慢性脑缺血的实验研究

CT Perfusion Study with Stress Test in Chronic Cerebral Ischimic Models

目的:利用慢性缺血动物模型探讨CT灌注负荷试验的应用价值。方法:42号鼠随机分6组SD大鼠的双侧椎动脉和右侧颈总动脉,实验组结扎分别在术后1天、3天、7天、14天、21天(每组7只)行CT灌注检查。每只大鼠行两次灌注检查:静息状态和负荷状态(吸入8%的CO210min后)。比较实验组和对照组两侧大脑半球(右/左)脑血流量和脑血容量的相对比值rCBF、rCBV的变化。结果:对照组大鼠两侧大脑半球灌注对称,静息状态下实验组rCBF、rCBV在血管结扎后均有明显下降,但很快即恢复正常水平(7天之后);而负荷状态下,rCBF、rCBV下降到7天时达到最低,之后逐渐恢复,在21天时与对照组比较仍有显著性差异(P<0.01)。负荷状态下rCBF、rCBV明显低于静息状态,统计学差异有显著性(P<0.01)。结论:相对于静息状态CT灌注,负荷试验显示了更严重的脑血液动力学损害。且两种状态下损害的时间过程不一致。提示负荷试验可更敏感地反应慢性脑缺血的状态。

Objective：To investigate the value of stress test perfusion CT in chronic ischemic animal models rats with bilateral vertebral arteries and the right common carotid artery occluded. Methods： 42 rats were randomly divided into six groups. Models of the experimental groups were built by ligating bilateral vertebral arteries and the right commen carotid artery,CT perfusion following surgery on Day 1, Day 3, Day 7, Day 14, and Day 21 respectively. Each rat received CT perfu-sion scan twice：baseline and stress test （inhalation of 8% CO2,lasting 10 min）. Right and left side of relative cerebral blood flow （rCBF） and ratio of cerebral blood volume （rCBV） of each group were analyzed. Results：The average rCBF and rCBV were 1.00 respectively in control group, rCBF and rCBV of experimental groups at stress status were decreased,but recovered rapidly to the normal level after 7 days. rCBF and rCBV decreased and reached the lowest point at 7 days, then recovered gradually,but still significantly lower than that of control group even at 21 days. Conclusion：Compared with baseline perfusion CT,stress test perfusion CT displays severer hemodynamic impairments,and allows further understanding of the blood flow perfusion of chronic ischemia subjects. Stress test perfusion CT is more sensitive in detecting chronic cerebral ischemia.