PET/MR Multimodal Quantitative Analysis of CBF and CMRGlc in Cerebral Ischemia

Inclusion Criteria: 1. Angiography diagnosed unilateral anterior circulation head carotid artery stenosis, the diameter of the tube was reduced by \>70%, and the contralateral anterior circulation and bilateral posterior circulation did not exceed the stenosis of \>50% of the diameter reduction; 2. Must have had a transient ischemic attack or ischemic stroke within the area of the diseased vessel within the past 12 months, with the most recent onset being more than 3 weeks; 3. MRI showed no new infarct lesions in the skull; 4. There is no infarct lesion in the previous pontine area; 5. Research participants and informants can complete relevant examinations and follow-ups; 6. Informed consent signed by the study participant or his/her authorized representative; Exclusion Criteria: 1. Poor image quality caused by head movement or other reasons during scanning 2. Presence of other neurological diseases that can cause brain dysfunction (such as depression, brain tumor, Parkinson's disease, metabolic encephalopathy, encephalitis, multiple sclerosis, epilepsy, brain trauma, normal pressure hydrocephalus, etc.) 3. Presence of other systemic diseases that can cause cognitive impairment, such as hepatic insufficiency, renal insufficiency, thyroid dysfunction, severe anemia, folic acid and vitamin B12 deficiency, specific infections (such as syphilis, HIV), alcohol and drug abuse, etc 4. Presence of other known diseases that may cause cognitive impairmentPresence of other known diseases that may cause cognitive impairment 5. Individuals with severe visual or hearing impairment, claustrophobia, or other conditions that prevent cooperation with MRI examination 6. Individuals suffering from diseases that make it impossible to cooperate with cognitive examinations 7. Refusal to sign the informed consent form at baseline