Health volunteers' inclusion criteria:

Age between 4-60; Male or female;

Exclusion criteria:

Exclude the volunteers with history of cerebrovascular disease.

Moyamoya disease patients' inclusion Criteria:

1.written informed consent had been obtained; 2. more than 4 years old and less than 60 years old; 3. cerebral digital subtraction contrast angiography (DSA) revealed severe stenosis or occlusion of the distal internal carotid or proximal middle and anterior cerebral arteries with prominent lenticulostriate 'moyamoya collaterals'; 4. received surgical revascularization;

Exclusion Criteria:

1. There are other vascular diseases, including systemic vasculitis, neurofibroma, meningitis, sickle cell disease, down's syndrome, and previous basilar radiotherapy; 2. Patients with cardiogenic embolism, including a history of atrial fibrillation, valvular disease or cardiac valve replacement; 3. Physical or subjective failure to cooperate with the examination or serious comorbid diseases.

m6A RNA modification in peripheral blood

Stage 1 stenosis of the carotid artery at its suprasellar portion, usually bilateral; Stage 2 moyamoya vessels begin to develop at the base of the brain; Stage 3 moyamoya vessels become more prominent as major trunks in the anterior circulation become severely stenotic or occluded; Stage 4 posterior cerebral arteries are occluded, moyamoya vessels begin to diminish and collateral pathways from extracranial circulation develop; Stage 5, moyamoya vessels are diminishing and extracranial circulation progresses; Stage 6, moyamoya vessels and the major cerebral arteries completely disappear, the cerebral hemispheres receive blood through the abnormal extracranial-intracranial anastomosis.

Higher scores mean a worse outcome.