This prospective cohort study aims to establish a large-scale cohort for primary stroke prevention in asymptomatic intracranial atherosclerosis (ICAS). Objectives include: characterizing risk factor and stenotic artery distributions; determining optimal TCD screening sentinel arteries; observing plaque progression/regression via HR-MRI; establishing vulnerable plaque evaluation systems through stroke event follow-up; and developing cognitive decline prediction models integrating hemodynamic parameters. All procedures (TCD, HR-MRI, neuropsychological assessments) are routine clinical examinations with minimal risk. Participation is voluntary. Initial TCD and qualifying HR-MRI scans incur standard fees; all follow-up imaging and neuropsychological assessments post-enrollment are provided free of charge.

Inclusion Criteria:

• Intracranial arterial stenosis confirmed by transcranial Doppler (TCD), clinically suspected to be of atherosclerotic origin
• No history of stroke or transient ischemic attack (TIA)
• Adequate temporal bone acoustic window penetrability

Exclusion Criteria:

• Clinically diagnosed non-atherosclerotic etiology-related intracranial arterial stenosis
• Poor temporal bone acoustic window penetrability
• Loss to follow-up

Transcranial Doppler (TCD)-detected asymptomatic intracranial atherosclerotic patients