摘要：
目的 探讨CT灌注成像(CTPI)联合CT血管造影(CTA)在颈内动脉系统短暂性脑缺血发作(TIA)诊断中的应用价值,并对颈内动脉系统TIA的病因、病理生理学机制进行研究. 方法 选取自2008年4月至2009年1月大连医科大学附属第一医院临床诊断为颈内动脉系统TIA的35例患者作为病例组,同期选取无颈内动脉系统TIA临床症状及体征的22例健康体检者作为对照组.病例组在发病＜48h内应用16排螺旋CT依次行CT平扫、CTPI及CTA检查,检测并对比病例组缺血区和对侧对照区以及病例组与对照组脑内感兴趣区的平均通过时间(MTT)、脑血流量(CBF)及脑血容量(CBV),分析其与CTA变化及临床表现的关系. 结果 35例患者中有28例(80％)在CT灌注图上发现与临床症状相对应的灌注异常区,其中MTT图上发现灌注异常区28例,CBF图上发现23例,而CBV图上仅15例;另外7例患者在所有灌注参数图上均未发现灌注异常区.35例患者中CTPI、CTA出现异常的对应关系存在以下4种情况:(1)CTPI发现灌注异常,且CTA显示其责任血管者有25例(71％),包括颈内动脉系统血管狭窄16例、血管多发软斑块13例、颈内动脉系统发育不良6例,并有多种病因共存现象.(2)CTPI发现灌注异常,而CTA未发现责任血管者有3例(9％).(3)CTPI未发现灌注异常,而CTA发现颈内动脉系统血管异常者有3例(9％).(4)CTPI未发现灌注异常且CTA未发现颈内动脉系统血管异常者有4例(11％). 结论 MTT是颈内动脉系统TIA在CTPI检查中最敏感、最主要的指标,而CBF、CBV的变化可反映患者不同的病理生理学状态.颈内动脉系统的低灌注是颈内动脉系统TIA的病理生理学基础之一,颈内动脉系统血管狭窄、多发粥样硬化斑块是颈内动脉系统TIA的主要病因.CTPI与CTA联合应用为颈内动脉系统TIA病因及发病机制的诊断提供了直接客观的影像学信息,并可以为TIA的个体化诊疗提供重要依据.%Objective To observe the changes of regional cerebral blood flow and blood-supply artery and study the value of computerized tomography perfusion imaging (CTPI) and computerized tomography angiography (CTA) in the clinical diagnosis of transient ischemic attack (TIA) of internal carotid artery system to further explore the etiological factors and pathophysiological mechanism of TIA of internal carotid artery system.Methods Thirty-five patients with TIA of internal carotid artery system,admitted to our hospital from April 2008 to January 2009,were enrolled into patient group,and 22 healthy subjects without TIA of internal carotid artery system symptoms and negative CTA features were enrolled as control group.These patients were examined with 16 slice CTPI and CTA in head and neck within 48 h of onset; the mean transmit time (MTT),cerebral blood flow (CBF) and cerebral blood volume (CBV) in the region of interests (ROIs) between the two sides of the patient group and between patient group and control group were analyzed,and the relationship with CTA features and clinical manifestations were discussed.Results Twenty-eight of 35 patients (80％) with TIA of internal carotid artery system revealed abnormal perfusion regions corresponding to clinical symptoms in CTPI,of which there were 28 revealing abnormal perfusion regions on MTT maps,23 on CBF maps,and only 15 on CBV maps.Other 7 patients showed normal results in CTPI.The correspondence relationship between CTPI and CTA abnormality had the following 4 types:(1) there were 25 patients (71％) with perfusion abnormalities accompanied by abnormal vascular supplying the abnormal perfusion region (convict vascular); among them,16 had carotid artery stenosis,13 had many weak vascular plaques,and 6 had carotid artery dysplasia; the coexistence of a number of factors and situation existed.(2) There were 3 patients (9％) with perfusion abnormalities in CTPI but without abnormal vascular in CTA.(3) There were 3 patients (9％) with abnormal vascular in CTA but without perfusion abnormalities in CTPI.(4) There were 4 patients (11％) had neither abnormal vascular nor perfusion abnormalities.Conclusions MTT is the most sensitive and primary indicator in CTPI of TIA of internal carotid artery system; the changes of CBF and CBV can reveal the various pathophysiological state of TIA of internal carotid artery system.The hypoperfusion is one of the pathophysiological bases of TIA of internal carotid artery system,and carotid artery stenosis and many weak vascular plaques may be the etiological factors of TIA of internal carotid artery system.CTPI combined with CTA is important to study the etiology of TIA.
