Overview

The study is to attain early recognition of the unstable plaques which have an imminent embolic risk in patients with intracranial atherosclerotic disease (IAD).

Eligibility

Inclusion Criteria:

• Inclusion Criteria for the Symptomatic Group:
  1. Patient is 30 to 85 years of age, inclusive.
  2. Patients who have an acute infarct in diffusion-weighted MRI compatible with artery-to-artery thrombo-embolism, a relevant intracranial atherosclerotic stenosis ≥60%, and MES detected by TCD.
  3. Patient who has no contra-indication for the proposed imaging tests.
  4. Patient understands the purpose and requirements of the study, and has provided an informed consent.
• Inclusion Criteria for the Asymptomatic Group:
  1. Patient is 30 to 85 years of age, inclusive.
  2. Patient who has a high-grade (>60%) intracranial stenosis (signal void in MR angiography) but without infarct in the corresponding vascular territory in DWI or T2-weighted sequence.
  3. Patient has no MES detected on TCD examination.
  4. Patient who has no contra-indication for the proposed imaging tests.
  5. Patient understands the purpose and requirements of the study, and has provided an informed consent.

Exclusion Criteria:

Subject who meets one or more of the following criteria cannot be recruited in the study:

1. Stroke etiology uncertain or unrelated to intracranial atherosclerosis, such as cardioembolism, Moyamoya disease, small vessel disease, etc.
2. A tandem stenosis >50% at proximal internal carotid artery.
3. Bleeding propensity: active peptic ulcer disease, major systemic hemorrhage within 30 days, thrombocytopenia (platelets <100 x 109/L), coagulopathy (INR >1.5).
4. A medical condition that would not allow the patient to adhere to the protocol or complete the study.