Eligibility CriteriaPatients suspected of having symptomatic ICAD at admission will be enrolled. All patients will receive a thorough evaluation to determine the cause of their ischemic event (TIA or ischemic stroke), including carotid duplex, transcranial Doppler, echocardiography, electrocardiogram, computed tomography (CT), CT angiography, MRI, magnetic resonance angiography (MRA), or digital subtraction angiography DSA.
Patients will be enrolled in this study according to if they met the following:
- ischemic stroke or TIA in the target territories of the intracranial anterior or posterior circulation within 90 days;
- Lack of coexistent≥50% ipsilateral extracranial carotid artery or vertebral artery stenosis;
- No potential sources of cardio-aortic embolism based on the modified Trial of ORG 10172 in Acute Stroke Treatment classification;
- Age ≥18 years;
- One or more atherosclerotic risk factors including hypertension, hypercholesterolemia, diabetes mellitus, cigarette smoking, and obesity.
Exclusion Criteria- Non-atherosclerosis vasculopathy such as vasculitis and arterial dissection diagnosed by comprehensive laboratory work (such as erythrocyte sedimentation rate or C-reactive protein elevations, antinuclear antibody, or antiphospholipid antibody positivity), vascular imaging, and clinical evaluation;
- Contraindication to MR examination, medical instability precluding MR examination.