Intracranial atherosclerotic disease is the most common cause of ischemic stroke in Asia, also in China. Currently, despite vascular recanalization therapy, statins are one of the main drug choices for treating atherosclerotic plaque. High resolution magnetic resonance imaging (HRMRI) can accurately assess the status of intracranial and extracranial arterial plaque, and has high consistency with histopathology. Thus, HRMRI technology has been widely used to monitor the efficacy of drug treatment for atherosclerotic plaque in clinical trials or practice.

As a non-invasive technique, HRMRI make it possible to assess the morphologic characteristics of vascular wall and plaque composition of intracranial artery in vivo. It can quantitative analysis including components such as lipid-rich necrotic core, fiber cap thickness, intra-plaque hemorrhage, calcification, etc. Therefore, it is crucial for evaluating the etiology of ischemic stroke and developing secondary prevention strategies.

At present, there is a lack of large-scale and prospective study to evaluate the etiology of ischemic stroke including cryptogenic stroke based on HRMRI. In this context, this study aims to establish a multi center HRMRI database of intracranial arteries among Chinese patients with ischemic stroke.

Inclusion Criteria:

• 1. Patient age ≥40 years
• 2. Time of stroke onset: within 2 week
• 3. Baseline NIHSS score ≤16
• 4. Ischemic stroke confirmed by head CT or MRI
• 5. Premorbid mRS ≤1
• 6. The degree of stenosis of extracranial arteries including internal carotid artery, vertebral artery on the lesion side ≤50%
• 7. The culprit plaque or possible culprit plaque with plaque burden of 40% or more found by HRMRI in the proximal part of the middle cerebral artery M1 segment or basilar artery of ipsilateral lesion
• 8. Signed informed consent

Exclusion Criteria:

• 1. Intracranial hemorrhage found by head CT
• 2. Had a contraindication to MRI,or could not complete required MRI sequences
• 3. Intracranial tumor, arteriovenous malformation, or aneurysm
• 4. Comorbidity with any serious diseases and life expectancy is less than one year
• 5. Pregnancy
• 6. Patients not suitable for this clinical studies considered by researcher

patients with ischemic stroke who performed HRMRI