Atherosclerotic intracranial arterial stenosis (AICAS) corresponds to luminal narrowing of the major intracranial arteries. The prevalence of intracranial atherosclerotic stenosis accounts for 33% to 67% of stroke or transient ischemic attack (TIA) cases in China and other countries in Asia. AICAS is also highly associated with the risk of stroke recurrence. Possible mechanisms of cerebral infarction secondary to AICAS are likely linked with hemodynamic compromise distal to site of stenosis.