摘要：

目的 探讨动态磁敏感对比增强灌注成像（DSC-PWI）在颞浅动脉-大脑中动脉搭桥术中的应用价值，为颞浅动脉-大脑中动脉搭桥术治疗颈内动脉或大脑中动脉重度狭窄和（或）闭塞提供脑血流灌注变化的影像学证据。 方法 共76 例行单侧颞浅动脉-大脑中动脉搭桥术患者，分别于术前1 个月和术后1 周内行头部MRI 常规和DSC-PWI 检查，观察手术前后基底节区层面（搭桥近端）和半卵圆中心层面（搭桥远端）大脑中动脉供血区脑血流动力学变化［包括相对脑血流量（rCBF）、相对脑血容量（rCBV）、相对平均通过时间（rMTT）和相对达峰时间（rTTP）］。 结果 术后患侧基底节区层面（搭桥近端）和半卵圆中心层面（搭桥远端）rCBF 均较术前升高（P = 0.000，0.001）；仅基底节区层面rCBV 较术前升高（P = 0.021）；基底节区层面和半卵圆中心层面rMTT（P = 0.000，0.000）和rTTP（P = 0.000，0.000）均较术前降低。 结论 颞浅动脉-大脑中动脉搭桥术可以改善大脑中动脉供血区脑血流灌注。DSC?PWI 能够完成对脑缺血区域血流动力学的评价，是评价手术疗效和动态观察脑血流动力学变化的最佳无创性技术。

关键词: 脑血管重建术, 颞动脉, 大脑中动脉, 颈内动脉, 动脉粥样硬化, 血流动力学, 磁共振成像

Abstract:

Objective  To explore the value of dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI) in superficial temporal artery-middle cerebral artery (STA-MCA) bypass and to provide radiological evidence for hemodynamic changes in STA-MCA bypass in the treatment of severe internal carotid artery (ICA) and MCA stenosis and/or occlusion.  Methods  A total of 76 cases (65 males and 11 females with average age of 55) who underwent STA-MCA bypass from January 2011 to February 2016 were included. Routine MRI and DSC-PWI were performed within one month before operation and within one week after operation. Hemodynamic changes [relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), relative mean transit time (rMTT) and relative time to peak (rTTP)] of MCA blood supplying area at basal ganglia section (proximal end) and centrum semiovale section (distal end) were compared before and after operation.  Results  Compared with before operation, rCBF was significantly increased after operation at ipsilateral basal ganglia section (proximal end, P = 0.000) and centrum semiovale section (distal end, P = 0.001). rCBV at basal ganglia section was significantly increased after operation (P = 0.021), while rCBV at centrum semiovale section had no significant difference compared with before operation (P = 0.844). rMTT (P = 0.000, 0.000) and rTTP (P = 0.000, 0.000) at ipsilateral basal ganglia section and centrum semiovale section were significantly reduced after operation.  Conclusions  STA-MCA bypass can improve cerebral blood perfusion of MCA blood supplying area. DSC-PWI could assess the hemodynamics of ischemic area, so it is the optimal noninvasive technology to evaluate the curative effect of bypass and observe cerebral hemodynamic changes dynamically.

Key words: Cerebral revascularization, Temporal arteries, Middle cerebral artery, Carotid artery, internal, Atherosclerosis, Hemodynamics, Magnetic resonance imaging