脑梗塞的危险因素是多方面,有遗传的,解剖的和环境的。一旦主要血管闭塞(如颈内动脉),血流可以通过原发或继发的侧支血管供应。原发血管可以很快起作用,而继发侧支则需要时间。因此原发侧支的大小和通畅性在颈内动脉严重狭窄或闭塞时是一个危险因素。作者应用常规MRI和3D MRA研究了29个病人的32个因颈内动脉闭塞而处于危险的半球。2例有双侧颈内动脉闭塞;另1例为巨大的腔 Risk factors for cerebral infarction are multifaceted, hereditary, anatomic and environmental. Once a major vessel occlusion, such as the internal carotid artery, blood flow can be supplied through the primary or secondary collateral vessels. Primary blood vessels can quickly play a role, while the secondary side branch takes time. Therefore, the size and patency of the primary collateral artery in the severe stenosis or occlusion is a risk factor. The authors used conventional MRI and 3D MRA to study the 32 hemispheres of 29 patients that were at risk for occlusion of the internal carotid artery. Two patients had bilateral occlusion of the internal carotid artery; another had a huge lumen