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Different presentations

Moyamoya can be associated with transient neurological episodes, stroke, seizures or headaches. These symptoms also occur in other conditions. A symptom list cannot confirm moyamoya or establish whether narrowing seen on a scan explains a person's symptoms.1

Ischemic events relate to insufficient blood supply; hemorrhagic events involve bleeding. The official AHA adult summary describes both, along with other neurological symptoms. Distinguishing the event type is part of clinical assessment, not something a reader can reliably do from headache or weakness alone.2

What the tests are asking

Brain MRI and vascular MRA provide different information. Digital subtraction angiography (DSA) examines the vascular pattern and collateral circulation. The revised Japanese criteria emphasize stenosis near the terminal intracranial internal carotid artery together with abnormal networks, and the assessment of competing explanations. They particularly emphasize angiography when unilateral findings or atherosclerosis complicate the interpretation.3

Perfusion and cerebrovascular-reserve assessments concern blood delivery and the circulation's capacity to respond. ESO discusses several methods and supports assessment through expert consensus. No single test sequence or result threshold determines treatment for everyone.4

Ask the clinician what question each test addresses: brain injury, artery anatomy, collateral pathways or blood-flow reserve. A report using the word stenosis is only one part of that discussion. If a test is repeated, ask which change the team is looking for and how the result could affect the plan.

Disease, syndrome and other causes

The 2021 Japanese revision permits a diagnosis with unilateral disease when the criteria are met. Bilateral means both sides; unilateral means one side. It also separates disease from certain associated-condition patterns. Its handling of atherosclerosis and hyperthyroidism differs from some older descriptions, so lists copied from different frameworks can mislead.3

Use the diagnostic framework named by the treating team. An associated condition does not make every neurological symptom moyamoya-related, and ordinary intracranial narrowing is not automatically moyamoya. A vascular stage describes features of the circulation; it isn't a stand-alone prognosis or an automatic indication for bypass.

Prepare for the assessment

Useful questions include: Which findings support this diagnosis? Which alternatives were considered? Is the concern ischemia, bleeding or an incidental vascular finding? Does the other side need assessment? What is known about blood-flow reserve? Who will coordinate further interpretation?

Bring the actual reports and a timeline of symptoms to your clinical team.

Sudden symptoms

For new sudden weakness, speech or vision difficulty, imbalance or an unexplained severe headache, call local emergency services immediately. Symptoms that resolve still require urgent assessment. Do not wait for routine imaging or a planned consultation.5

References

  1. US National Library of Medicine. MedlinePlus Genetics: Moyamoya disease. Webpage. Source ↩
  2. American Heart Association. Top Things to Know: Adult Moyamoya Disease and Syndrome. 23 August 2023. Statement doi:10.1161/STR.0000000000000443. Source ↩
  3. Kuroda S et al. Neurologia medico-chirurgica. 2022;62:307–312. doi:10.2176/jns-nmc.2022-0072. Source ↩
  4. Bersano A et al. European Stroke Journal. 2023;8:55–84. doi:10.1177/23969873221144089. Corrected March 2023. Source ↩
  5. US Centers for Disease Control and Prevention. Signs and Symptoms of Stroke. 19 May 2026. Source ↩