Inclusion Criteria:

• Cerebral infarction within 2 weeks from the onset or TIA with corresponding acute ischemic brain lesions on MRI within 2 weeks from the onset
• Age: more than 35 years of age
• Patient with significant focal stenosis in the M1 segment of middle cerebral artery (MCA) or basilar artery (BA) with acute ischemic lesions on magnetic resonance imaging (MRI) within the vascular territory of the stenosed artery.

Exclusion Criteria:

• Patients with any contraindications to the treatment with antiplatelet therapy
• Patients with potential cardiac embolic source; prosthetic valve, atrial fibrillation, atrial flutter, left atrial/atrial appendage thrombus, sick sinus syndrome, left ventricular thrombus, dilated cardiomyopathy, akinetic or hypokinetic left ventricular segment, atrial myxoma, Infective endocarditis, mitral valve stenosis or prolapse, mitral annuls calcification, left atrial turbulence, nonbacterial endocarditis, congestive heart failure, recent myocardial infarction (within 4 weeks)
• Patients with more than 50% stenosis in the parent artery of symptomatic stenosis
• Bleeding diathesis
• Chronic liver disease (ALT > 100 or AST > 100) or chronic renal disease (creatinine > 3.0mg/dl)
• Anemia (hemoglobin < 10mg/dl) or thrombocytopenia (platelet count less than 100,000/mm3)
• Nonatherosclerotic vasculopathy; patients with clinical characteristics suggesting arterial dissection, moyamoya disease, Takayasu’s arteritis, radiation associated angiopathy, and other vasculitis.
• Severe stroke: NIH stroke scale : more than 16
• Pregnant or lactating patients
• Chronic user of NSAIDs
• Thrombolytic therapy for the symptomatic stenosis
• Symptomatic stenosis scheduled for angioplasty
• Patients with pacemaker or any other contraindications to MRI