Clinical Research Directory

Inclusion Criteria: * At least 18 years old; * Medium or severe stenosis of the internal carotid artery, middle cerebral artery, V4 segment of vertebral artery or basilar artery \[stenosis degree: 50% \~ 99%, confirmed by CTA, MRA or DSA\]; * Accept high resolution magnetic resonance angiography; The patient or the legal representative of the patient is able and willing to sign an informed consent form Exclusion Criteria: * Non-atherosclerotic intracranial and extracranial artery stenosis, such as dissection, smoke disease, etc.; * There are contraindications to MRI, such as claustrophobia, metal implants, etc.; * Renal insufficiency, elevated serum creatinine (more than twice the upper limit of normal); * Patients with severe cardiopulmonary diseases were considered unsuitable for this study; * Gadolinium contrast agent allergy; * Participants who were unable to complete the study due to mental illness, cognitive or emotional disorder.