CT灌注成像联合无创血管造影评估头颈部动脉狭窄的价值

目的 探讨CT灌注成像（computed tomography perfusion, CTP）联合颈部无创血管造影评估颈内动脉（internal carotid artery, ICA）及大脑中动脉（middle cerebral artery, MCA）狭窄程度及侧支循环开放程度与脑灌注的关系。方法 80例ICA和83例MCA经颈动脉CE-MRA及头颈动脉CTA诊断为单侧动脉狭窄的患者纳入本研究中，观察CTP成像特点，对各组患、健侧相对脑血流量(relative cerebral blood flow, rCBF)增加率、相对脑血容量（relative cerebral blood volume, rCBV）增加率，达峰时间（time to peak, TTP）增加率，平均通过时间（mean transit time, MTT）增加率定量分析。结果 共21例ICA和33例MCA狭窄出现CTP异常，ICA狭窄程度与患、健侧TTP增加率有相关性（P＜0.05）。而大脑中动脉狭窄程度还与rCBV增加率、MTT增加率相关（P＜0.05）。将动脉中重度狭窄组患者根据侧支循环开放程度分级，侧支循环不良组出现灌注异常概率较大，与良好组之间TTP增加率差异具有统计学意义（P＜0.05）。结论 TTP是评价脑灌注异常的最敏感指标。CTA联合CTP可直观显示血管狭窄程度及远端的血流动力学情况，评价侧支循环情况，对临床个体化治疗具有重要意义。
Objective To evaluate the application of CT perfusion (CTP) and carotid system noninvasive angiography in assessment of internal carotid artery (ICA) and middle cerebral artery (MCA) and degree of openness of collateral circulation. Methods One hundred and sixty three patients with intra- or extra-cranial arterial stenosis diagnosed by contrast-enhanced MR angiography (CE-MRA) and head and neck CT angiography (CTA) were enrolled in the study, including 80 patients with ICA stenosis and 83 patients with MCA stenosis. To discriminate the ischemic foci, the parameter maps of rCBF increase rate, rCBV increase rate, TTP increase rate, MTT increase rate were obtained. Results CTP results showed that 21 patients with ICA stenosis and 33 patients with MCA stenosis had abnormal perfusion. The degree of ICA stenosis was correlated with TTP increase rate (P<0.05); the degree of MCA stenosis was correlated with rCBV increase rate and MTT increase rate (P<0.05). In patients with moderate to severe stenosis of carotid system, the abnormal perfusion had higher probability of poor collateral circulation. There was significant difference in the rate of TTP increase between the poor and the good collateral circulation groups in patients with intra- or extra-cranial arteries stenosis (P<0.05). Conclusion TTP is sensitive to depict the abnormal perfusion of brain, and is positively correlated with arterial stenosis. CTA combined with CTP, can not only visually show the hemodynamic changes and collateral circulation of responsible arteries. They can be comprehensive evaluation of carotid artery stenosis on the individual