MRI在颅内动脉狭窄、闭塞诊断中的应用

目的评价头颅三维增强磁共振血管造影（3DCE-MRA）结合MRI常规扫描诊断颅内动脉狭窄、闭塞的临床意义。方法3D CE-MRA及头颅MRI常规扫描发现颅内大动脉明显狭窄或闭塞116例，其中43例同期行DSA检查。常规扫描采用横断面T1W、T2W和冠状面T2W成像；3DCE-MRA用超快速三维梯度回波序列（3DFISP），钆对比剂（Gd-DTPA）0．2mmol／kg，注射速率3ml／秒，行增强前、增强后动脉期及静脉期3次扫描，每次扫描时间约10秒，图像减影后至工作站上三维重建。结果116例中由动脉粥样硬化引起的颅内动脉狭窄或闭塞占72．4％；狭窄或闭塞以颈内动脉系统为多，占总狭窄或闭塞的68．7％；颈内动脉系统闭塞或狭窄伴随的脑梗塞高于椎一基底动脉系统；脑梗塞的发生与侧支血管是否形成有关；43例同期行DSA检查者中，80．4％狭窄或闭塞的3DCE-MRA与DSA一致。结论头颅3DCE-MRA结合常规MRI扫描作为一种无创性影像检查技术，可快速而准确地显示颅内大动脉狭窄或闭塞及其相对应的脑梗塞，一次检查即能为临床提供较为全面的信息，可作为脑梗塞患者的首选诊断方法。

The diagnostic MR imaging in intracranial artery stenosis or occlusion

Objective To assess the clinical value of cerebral three-dimensional dynamic contrast-enhanced MRA(3D CE-MRA) and MR scanning in the diagnosis for intracranial artery stenosis or occlusion.Methods Prominent intracranial arterial stenosis or occlusion was found in 116 cases with cerebral 3D CE-MRA and MR scanning.Among them,43 cases were performed with DSA simultaneously.Cerebral MR scanning included transverse T1W and T2W,and coronal T2W.A three-dimensional fast imaging with steady state precession(3D FISP) was used for 3D CE-MRA with Gd-DTPA 0.2 millimol per kilogram for body weight.The source images were subtracted from mask images and transferred to computer workstation.All images were subsequently post-processed using three-dimensional reconstruction.Results Of 72.4% of prominent intracranial arterial stenosis or occlusion were caused by atherosclerosis.Stenosis or occlusion mainly occurred in internal carotid arterial system,and was up to 68.7% of all cases.Cerebral infarctions due to internal carotid arterial system were higher than those caused by vertebrobasilar arterial system.Infarctions were related to collateral arteries.There was correlation between 3D CE-MRA and DSA in 80.4% of 43 with two examinations simultaneously.Conclusions Cerebral 3D CE-MRA and MR scanning,as a fast,noninvasive and efficient technique,can accurately demonstrate intracranial arterial stenosis or occlusion with relative cerebral infarction.It can provide overall and helpful information for treatment planning.3D CE-MRA could be used as the first choice of diagnosis in cerebral infarctions.