Call 911 for sudden weakness, facial droop, trouble speaking, vision loss, or a sudden severe headache, even if symptoms improve.
What is moyamoya?
Moyamoya is a condition in which major arteries near the base of the brain progressively narrow or become blocked. Small collateral vessels develop to help carry blood around the narrowing, but this alternative circulation may be fragile or insufficient. The term moyamoya disease is used when there is no associated condition explaining the pattern. Moyamoya syndrome describes a similar vessel pattern associated with another disorder.
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Why it matters for stroke and TIA
Reduced blood supply can cause transient ischemic attacks, or TIAs, and ischemic strokes. Some patients develop bleeding in the brain. Headaches, seizures, and difficulties with thinking can also occur. A TIA may last only minutes, but it should not be dismissed because the symptoms went away. Evaluation looks at your symptoms together with the condition of the vessels and the amount of blood reaching the brain.
How imaging guides the next step
MRI evaluates brain tissue, while MRA or CTA evaluates the arteries. A catheter cerebral angiogram can define the narrowed vessels and collateral circulation in greater detail when needed for diagnosis or treatment planning. Perfusion testing assesses blood delivery to the brain. These studies answer different questions: the angiogram maps the blood vessels; perfusion imaging helps show how well the brain is being supplied.
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An individualized treatment plan
A vascular neurologist and cerebrovascular surgeon consider symptoms, prior strokes or bleeding, blood-flow studies, and the risks of each option. Medicines may be used for selected patients, but they do not reverse the narrowing. Revascularization surgery creates another route for blood to reach the brain and may be recommended for appropriate patients. Options include direct bypass, indirect procedures that encourage new vessels to grow, or a combination. Routine angioplasty or stenting is not the standard approach to moyamoya narrowing.
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Preparing for a specialist visit
Bring your actual MRI, MRA, CTA, or angiogram images as well as the reports, hospital discharge records, and an up-to-date medication list. Write down any brief episodes of weakness, speech difficulty, or vision change and when they occurred. Ask which findings would lead to surgery, what follow-up imaging is needed, and whom to call if symptoms change. Decisions about aspirin, blood pressure, hydration, and activity should be individualized rather than changed on your own.
Common questions
Is moyamoya the same as cholesterol plaque?
No. Moyamoya is a distinct pattern of progressive arterial narrowing and collateral formation. Imaging and clinical assessment help distinguish it from atherosclerosis and other causes of narrowed brain arteries.
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Why might I need an angiogram after an MRI?
The studies provide different information. An angiogram may be recommended to map collateral routes and small vessels more precisely or to plan surgery. Your specialist should explain what additional question it will answer.
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Does every patient need surgery right away?
No single plan fits everyone. The timing and type of treatment depend on symptoms, brain injury, blood flow, and the balance of procedural benefits and risks. New stroke symptoms always require immediate emergency evaluation.
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Your next step
Sources & further reading
This guide explains general care options. Your treating team will recommend an evaluation and treatment plan for your individual situation.