The epidemiology of TOAST classification in Asian patients seems to differ due to the higher rates of large-artery atherosclerosis. The complex pathology of atherosclerosis could lead to recurrent stroke, including shear stress on the endothelium, disturbance of the flow, occlusion at the origin of the perforating artery, and other complications (plaque inflammation, plaque hemorrhage, plaque rupture) that could lead to stroke and recurrent stroke. Therefore, The exact determination of the etiology of stroke due to atherosclerosis is the most critical factor for treatment and prognostic. On the other hand, HR-MRI could be a useful imaging modality to evaluate the characteristics of plaque in stroke patients due to atherosclerosis stenosis, which will help us find out the etiology of stroke. Previous studies have demonstrated its prognosis value in predicting recurrent stroke in the same vascular territory. The investigators hypothesize that with an appropriate evaluation, HR-MRI could help to predict recurrent stroke in the same vascular territory in patients with high-risk plaque characteristics on HR-MRI. These findings could contribute to individual treatment according to etiology.

The investigators intend to conduct a study to determine the correlation between plaque characteristics and recurrent stroke in the same vascular territory in ischemic stroke patients due to middle cerebral artery stenosis.

The epidemiology of TOAST classification in Asian patients seems to differ due to the higher rates of large-artery atherosclerosis 1. The complex pathology of atherosclerosis could lead to recurrent stroke, including shear stress on the endothelium, disturbance of the flow, occlusion at the origin of the perforating artery, and other complications (plaque inflammation, plaque hemorrhage, plaque rupture) that could lead to stroke and recurrent stroke 2. Therefore, The exact determination of the etiology of stroke due to atherosclerosis is the most critical factor for treatment and prognostic. On the other hand, HR-MRI could be a useful imaging modality to evaluate the characteristics of plaque in stroke patients due to atherosclerosis stenosis, which will help us find out the etiology of stroke 3. Previous studies have demonstrated its prognosis value in predicting recurrent stroke in the same vascular territory 4. The investigators hypothesize that with an appropriate evaluation, HR-MRI could help to predict recurrent stroke in the same vascular territory in patients with high-risk plaque characteristics on HR-MRI. These findings could contribute to individual treatment according to etiology 5,6.

The investigators intend to conduct a study to determine the correlation between plaque characteristics and recurrent stroke in the same vascular territory in ischemic stroke patients due to middle cerebral artery stenosis

Inclusion Criteria:

• Patients who had a first-time ischemic stroke due to MCA atherosclerosis stenosis more than 50% and admitted to our hospital within 7 days after onset.
• Patients are more than 45 years old.
• Patients had HR-MRI and have done the full stroke workup (including carotid duplex scanning, fasting lipid profile, Holter ECG 24 hours, cardiac ultrasound,...)

Exclusion Criteria:

• Patients also have stenosis of the carotid artery (more than 50%) on the same side of ischemic stroke.
• Patients also have an ischemic stroke in territories other than MCA territory.
• Patients had any characteristics that suggested other causes for their stenosis, including moyamoya, dissection, and inflammation on their MRI and HR-MRI.
• Patients with evidence suggestive of cardioembolism (Atrial fibrillation, decreased EF <50%, recent heart attack in 3 weeks, rheumatic valvular heart disease, dilated cardiopathy, sick sinus syndrome, infective endocarditis).
• Any signs suggestive of autoimmune disease or increased coagulation state.
• Patients with severe concomitant disease could affect the 6-month follow-up of the patients.

The investigators would include patients who had ischemic stroke due to middle cerebral artery (MCA) stenosis (>50%)

When there is an appropriate request, the investigators will consider and provide anonymous data

The data will be available after the study has finished for at least 1 year and will be available for 3 years

Upon reasonable request