Comparison of Cerebral Artery Pressure Gradient and Cerebral Blood Flow Measured by Arterial Spin Labeling

The goal of this observational study is to explore the ability of intravascular pressure gradients to identify hemodynamic disturbance in patients with intracranial atherosclerotic diseases (ICAS). The main questions that aim to answer are:The correlation between intravascular pressure gradient and cerebral blood flow (CBF)The threshold for intravascular pressure gradients to predict hemodynamic disturbance in ICASPatients will undergo intravascular pressure measurement and arterial spin labeling (ASL) for CBF during pre- and post-operation respectively.

Inclusion Criteria:Patients aged 40 years or older.Patients with transient ischemic attack (TIA) or nondisabling ischemic stroke caused by a focal ICAS lesion located in intracranial anterior circulation (vertebral artery, basilar artery or intracranial internal carotid artery and their major branches).50% to 99% stenosis (calculated by modified WASID method) of responsible arterial occlusion, confirmed by digital subtraction angiography (DSA).Informed of the study protocol and objectives.Exclusion Criteria:Non-atherosclerotic MCA stenosisCombined with moderate or severe stenosis of other extracranial and intracranial arteriesPrevious endovascular treatment or surgery for cerebrovascular diseasesLarge cerebral infarction (more than 1/2 MCA perfusion area)Combined with other neurological diseases, such as aneurysm, arteriovenous malformation, tumor, hydrocephalus, cerebral trauma, cerebral hemorrhage, multiple sclerosis, epilepsy and intracranial infection.Vascular abnormality or stunting, resulting in the impossibility of endovascular interventionLiver and kidney dysfunction, or severe allergy to the contrast agentSevere coagulation dysfunctionPregnancy or in the preparation for pregnancyPatients who cannot tolerate or do not allow MR screening, including metal implanting and claustrophobiaPatients with severe dementia or mental disorders, who cannot cooperate with examination