Result: MR angiography can clearly display the middle-above degree stenosis and occlusion in the main branches of the arteriae cerebri such as arteriae carotis inter-na, arteriae vertebralis, arteriae basilaris, arteriae cerebri anterior, media, posterior. 结果:MRA能较为清晰地显示颈内动脉、椎、基底动脉、大脑前、中、后动脉主干的中度以上狭窄或闭塞。