This study aims to compare image-based characteristics of carotid walls between symptomatic side and the opposite side. The design of this study is phase IV, prospective observational study.

Atherosclerosis of craniocervical arteries are one of most important causes of stroke. Carotid artery is the most frequent site of atherosclerosis. Recent research in carotid artery covers not only morphology of lumen but also direct visualization of carotid plaque or vessel wall. Vulnerable carotid plaques share pathologic features of intra-plaque inflammation and hemorrhage. There have been reports about post-contrast SWI in the field of vascular imaging. We hypothesized SWI is so sensitive to gadolinium based contrast agent and hemorrhage that contrast-enhanced SWI can visualize vulnerable carotid plaque. The purpose of this study is to investigate gadolinium-enhanced SWI in detection of vulnerable carotid plaque and compare it with MP-RAGE and DANTE T1-SPACE. This can be used to guide proper treatment for stroke.

Inclusion Criteria:

• Patients with acute or recent (within 3months) stroke or TIA
• 50-99% stenosis of internal carotid artery by NASCET criteria
• Written informed consent, prior to registration

Exclusion Criteria:

• Hemorrhagic stroke
• Previous history of carotid endarterectomy (CEA), angioplasty, or stenting
• Contraindication for MR imaging
• Hypersensitivity to gadolinium based contrast media
• Pregnant or lactating women
• Patients under age of 19-year-old
• Renal condition : eGFR < 60
• Patients unable and/or unwilling to comply with treatment or study instructions.

Patients with acute or recent (within 3months) stroke or TIA (transient ischaemic attack)