Study on Multimodal Imaging and Molecular Imaging Techniques in Degenerative Dementia

Inclusion Criteria: * Patients aged ≥50 and ≤85 years old, male or female; * Meet the diagnostic criteria for dementia or MCI; * Neuropsychological score: MMSE 15-28 points, CDR ≤ 1 point; ④ Patients and their families are informed and sign the informed consent form Exclusion Criteria: * The presence of other neurological diseases that may cause brain dysfunction (such as depression, brain tumors, Parkinson's disease, metabolic encephalopathy, encephalitis, multiple sclerosis, epilepsy, brain trauma, normal intracranial pressure hydrocephalus, etc.); * The presence of other systemic diseases that may cause cognitive impairment (such as liver dysfunction, renal dysfunction, thyroid dysfunction, severe anemia, folic acid or vitamin B12 deficiency, syphilis, HIV infection, alcohol and drug abuse, etc.); * Suffering from a disease that makes it impossible to cooperate with cognitive examinations; * The presence of contraindications to MRI; * The presence of mental and neurological retardation; * Refusing to draw blood; * Refusing to sign the informed consent form.