Objective To investigate the effect of vasospasm on cerebral perfusion and the relationship of vasospasm with DCI by CTP.Methods Fivty-six consecutive SAH patients were studied with CT angiography (CTA) and CT perfusion (CTP) on admission and within 14 days after admission or at time of clinical deterioration.CTP values (cerebral blood volume, CBV) cerebral blood flow (CBF) and mean transit time (MTT), degree of vasospasm on CTA, and occurrence of DCI were recorded.The correspondence of the flow territory of the most spastic vessel with the least perfused region was evaluated, and differences in perfusion values and occurrence of DCI between degrees of vasospasm were calculated.Results Twentyone patients had no vasospasm, 24 were moderate, and 11 were severe.In 65％ of patients with spasm, the flow territory of the most spastic vessel corresponded with the least perfused region.Six of eleven patients with severe, nine of twenty four with moderate, and four of twenty one patients wiih no vasospasm had DCI.Conclusion Vasospasm decreases cerebral perfusion, but corresponds with the least perfused region in only two thirds of our patients.Furthermore, almost half of patients with severe vasospasm do not have DCI.Thus, although severe vasospasm can decrease perfusion, it may not result in DCI.%目的 利用脑血流灌注法显示脑血管痉挛状态对脑组织血流所产生的效应和脑血管痉挛与迟发性脑缺血(DCI)关系.方法 利用CT血管造影(CTA)技术和CT灌注(CTP)技术研究了56例多次蛛网膜下腔出血的患者,选择的时机是刚入院,入院后14 d或临床症状有所恶化的时间段.利用CTP的指标[脑血容量(CBV),脑血流量(CBF)和平均通过时间(MTT)],记录CTA图像上显示的脑血管痉挛程度和迟发性局灶脑缺血的发生,评估最为痉挛的脑血管支配区域与脑灌注图上最少血流灌注面积之间的相关性,不同程度下的脑血管痉挛导致在脑血流灌注上和DCI的发生之间的差异.结果 21例患者没有脑血管痉挛,24例患者中等程度痉挛,11例患者是严重痉挛.有血管痉挛的65%的患者中,最为痉挛的血管的血流区域与最少的脑缺血灌注区域相一致.在严重的脑缺血的区域和没有血管痉挛的区域之间有显著CBF的不同.在11例有严重脑血管痉挛的患者中,有6例出现迟发性局灶脑缺血;在24例有中度脑血管痉挛的患者中,有9例出现迟发性局部脑缺血;且在21例没有脑血管痉挛的患者中,有4例出现DCI.结论 血管的痉挛降低了脑血流的灌注,但只有2/3的病例脑血管痉挛与乏血供的灌注区域相一致,而且,几乎1/2的具有严重脑血管痉挛的患者没有发生DCI.因此,虽然严重的脑血管痉挛能降低脑血流的灌注水平,但是血管痉挛不会直接导致DCI.
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