Diagnosis

Moyamoya disease is usually diagnosed by a neurologist who specializes in the condition. The specialist will review your symptoms and your family and medical history, and perform a physical examination. Several tests are generally needed to diagnose moyamoya disease and any underlying conditions.

Tests may include:

• Magnetic resonance imaging (MRI). An MRI uses powerful magnets and radio waves to create detailed images of your brain. Your doctor may inject a dye into a blood vessel to view your arteries and veins and highlight blood circulation (magnetic resonance angiogram). Your doctor may recommend a perfusion MRI if available. This type of imaging can measure the amount of blood passing through the vessels and how critical the reduction of blood supply to the brain is.
• Computerized tomography (CT) scan. A CT scan uses a series of X-rays to create a detailed image of your brain. Your doctor may inject a dye into a blood vessel to highlight blood flow in your arteries and veins (CT angiogram). This test can't diagnose early stages of moyamoya disease, but may still be helpful in identifying abnormal blood vessels.
• Cerebral angiogram. In a cerebral angiogram, your doctor inserts a long, thin tube (catheter) into a blood vessel in your groin and guides it to your brain using X-ray imaging. Your doctor then injects dye through the catheter into the blood vessels of your brain. The contrast conforms to the shape of the blood vessels to make them more visible under X-ray imaging.
• Positron emission tomography (PET) scan or single-photon emission computerized tomography (SPECT). In these tests, you're injected with a small amount of a safe radioactive material and places emission detectors over your brain. PET provides visual images of brain activity. SPECT measures blood flow to various regions of your brain.
• Electroencephalogram (EEG). An EEG monitors the electrical activity in your brain via a series of electrodes attached to your scalp. Children with moyamoya disease often exhibit abnormalities on EEG.
• Transcranial Doppler ultrasound. In surgical transcranial Doppler ultrasound, sound waves are used to obtain images of your head and sometimes your neck. Doctors may use this test to evaluate blood flow in blood vessels in your neck.

If necessary, your doctor may order other tests to rule out other conditions.