The Longitudinal Cohort of Cerebral Small Vessel Disease in Ruijin Hospital

The goal of this observational study is to learn about neuroimage and biomarkers in the cerebral small vessel disease. The main questions it aims to answer are: * How does neurovascular coupling change during the progression of CSVD? * How is the pattern/mapping of alterations in CSVD biomarkers? Participants will be observed and visit the research center annually to perform multi-modal MRI, PET, neuropsychological tests, and blood tests.

Inclusion Criteria: 1. Age ≥18 years. 2. Evidence of cerebral small vessel disease (CSVD) on brain MRI, meeting at least one of the following imaging criteria: * White matter hyperintensities (WMH) with a total Fazekas score ≥2; * Fazekas score =1 with at least two vascular risk factors (hypertension, hyperlipidemia, diabetes mellitus, obesity, current smoking, or a history of vascular events other than stroke); * Fazekas score =1 accompanied by the presence of lacunes; * Imaging evidence of a recent subcortical lacunar infarction. 3. Independent in activities of daily living (modified Rankin Scale \[mRS\] ≤2). 4. Able and willing to provide written informed consent. Exclusion Criteria: 1. Acute ischemic stroke with a diffusion-weighted imaging (DWI) lesion \>20 mm in diameter. 2. Acute intracerebral hemorrhage. 3. Acute subarachnoid hemorrhage, a history of aneurysmal subarachnoid hemorrhage or cerebrovascular malformation, or the presence of an untreated intracranial aneurysm \>3 mm in diameter. 4. Previously diagnosed neurodegenerative disorders, such as Alzheimer's disease (AD) or Parkinson's disease (PD). 5. Definite non-vascular white matter diseases, including multiple sclerosis, adult-onset leukodystrophy, metabolic encephalopathy, or other non-vascular white matter disorders. 6. Major psychiatric disorders diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). 7. Contraindications to MRI (e.g., severe claustrophobia or MRI-incompatible implants). 8. Severe systemic diseases (e.g., active malignancy) with an expected life expectancy of less than 5 years. 9. Inability to complete scheduled follow-up because of geographic, logistical, or other reasons. 10. Concurrent participation in another interventional clinical trial.