Stanford Moyamoya Center


Based on the patients' symptoms and history, the physician may order one or all of these tests before making a decision about treatment.

Magnetic Resonance Imaging (MRI)
This allows physicians to examine brain structures and detect any strokes that might have occurred.

The arrows on this MRI of the brain shows a patient with a large stroke from moyamoya.

Cerebral Angiogram
This is the definitive test that confirms the diagnosis of moyamoya. "Contrast" (or dye) is injected into arteries to reveal the anatomy of the arteries of the brain and scalp. This is a minimally invasive test that requires patients to stay at the hospital for several hours. This test assesses the severity of moyamoya and its results guide treatment options, which are determined by how severe the disease is and what the external (scalp) blood supply is.

Side view of a normal angiogram.
MCA = middle cerebral artery
ACA = anterior cerebral artery
ICA = internal carotid artery
Angiogram of a patient with moyamoya disease. You can see the MCA and ACA vessels are impaired and moyamoya vessels have appeared along with other collateral vessels.

MRI/ Nova scans are a new technique useful for determining the quantitative volume of blood flowing through brain arteries. This information aids physicians in determining if areas of the brain are getting too much or too little flow. It is used during the pre op MRI and at the post op MR outpatient appointments.

Xenon CT Scans
This test reveals blood flow to regions of the brain to determine if enough blood is reaching all areas. Patients breathe xenon (an odorless, colorless gas), which acts as a contrast agent to show regions of low and high blood flow.

Note the areas of red and yellow, which indicate a higher volume of blood flow to the brain when challenged with Diamox.

Neuropsychological Assessment
As part of the presurgical diagnostic process, an evaluation of mental abilities (such as memory) is performed. These abilities can be affected by moyamoya disease. The evaluation, which consists of paper and pencil tests and questions, provides a baseline and provides the team information about how the brain is functioning.

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