CTP联合CTA对慢性脑缺血患者血流动力学的评价

Evaluation of CT perfusion and CT angiography in cerebral hemodynamic changes in patients with chronic cerebral ischemia

目的：利用CT灌注（CTP）和CT血管成像（CTA）探讨慢性脑缺血患者脑血流动力学变化及其与脑供血动脉狭窄、血管性认知功能障碍之间的关系。方法：对55例临床拟诊为慢性脑缺血的患者行常规头颅CT平扫、CTP及CTA检查,应用简易智能状态检查（MMSE）量表评定受试者的智能状态。结果：根据平均通过时间（MTT）、达峰时间（TTP）图灌注延迟范围将灌注表现分为3型：Ⅰ型为大脑中动脉和/或大脑前动脉供血区广泛性低灌注22例;Ⅱ型为分水岭区局限性低灌注21例;Ⅲ型为灌注正常12例。颈内动脉（ICA）或大脑中动脉（MCA）的重度狭窄或闭塞所致脑灌注异常（Ⅰ、Ⅱ型）明显高于轻中度狭窄者（χ^2=29.49,P〈0.01）,Ⅲ型未见ICA或MCA的重度狭窄或闭塞。ICA或MCA狭窄程度与脑灌注异常之间呈正相关（Spearman′sr=0.74,P〈0.01）。脑灌注Ⅰ、Ⅱ型患者MMSE评分均低于正常值（P〈0.01）,且以Ⅰ型为著（P〈0.01）,Ⅲ型MMSE评分正常。结论：慢性脑缺血患者脑血流低灌注与ICA或MCA狭窄程度密切相关,在血管性认知功能障碍的发病机制中起着重要作用。

Objective：Using CT perfusion （CTP） and CT angiography （CTA） to investigate the cerebral hemodynamic changes and the relationship between the hemodynamics and cerebral artery stenosis or cognitive impairment in patients with chronic cerebral ischemia.Methods：Conventional cerebral plain CT,CTP and CTA were performed on 55 patients with clinically diagnosed chronic cerebral ischemia.Cognitive scores were evaluated on these patients by using an informant questionnaire （mini-mental state examination,MMSE）.Results：Three types of CTP were found according to the extents of abnormalities on mean transit time （MTT） and time to peak （TTP）,including typeⅠ：extensive hypoperfusion involving the middle cerebral arterial and/or anterior cerebral arterial territories （22 patients）,type Ⅱ：localized perfusion deficits involving predominantly the ipsilateral border zone areas （21 patients）,type Ⅲ：normal perfusion （12 patients）.The incidence of hypoperfusion （typeⅠorⅡ） in patients with severe internal carotid artery/middle cerebral artery （ICA/MCA） stenosis or occlusion was significantly higher than that with mild to moderate ICA/MCA stenosis （χ^2=29.49,P〈0.01）.No patient with severe ICA/MCA stenosis or occlusion was seen in type Ⅲ.There was a positive correlation between the degree of ICA/MCA stenosis and cerebral hypoperfusion （Spearman′s r=0.74,P〈0.01）.Cognitive scores in patients with type Ⅰ or Ⅱ cerebral perfusion were lower than normal value （P〈0.01） and the former was even more significant （P〈0.01）,and those with type Ⅲ cerebral perfusion were normal.Conclusion：Cerebral hemodynamic hypoperfusion is closely correlated with the degree of ICA/MCA stenosis,which plays an important role in the pathogenesis of vascular cognitive impairment in patients with chronic cerebral ischemia.