Correlation Between Deep Medullary Veins and Cognitive Dysfunction in Cerebral Small Vessel Disease

1. Inclusion Criteria 1. Age 50 \~ 85 years old. 2. The diagnostic criteria of CSVD patients with cerebral small vessel diseases should be in accordance with the 2015 Chinese Consensus on the diagnosis and treatment of cerebral small vessel Diseases formulated and recommended by the Cerebrovascular Division of Chinese Society of Neurology, Chinese Medical Association. MRI examination revealed the presence of one or more of the major imaging features of CSVD as proposed by the 2013 International Standards Reporting Group on Neuroimaging of Vascular Changes. 3. No large vessel stenosis (stenosis rate \> 50%) was found after head and neck vascular examination (CTA, MRA, DSA or TCD combined with carotid ultrasound). 4. The vital signs are stable and can cooperate with the examination. 5. Informed consent signed by the patient or legal representative. 2. Exclusion Criteria: 1. Cerebral infarction or cerebral hemorrhage caused by large vascular disease; And CTA/MRA of the head and neck showed great vessel stenosis (stenosis rate \> 50%). 2. Patients with secondary white matter lesions caused by poisoning, inflammation, tumor and other pathological changes. 3. Cognitive impairment and gait impairment caused by other causes (such as Alzheimer's disease, Parkinson's disease, depression, etc. 4. Patients with contraindications of magnetic resonance examination. 5. Illiterate or unable to cooperate with cognitive assessment due to severe hearing and visual impairment.