Moyamoya Disease

Moyamoya disease is a chronic, progressive cerebrovascular disease that affects the blood vessels in your brain. More specifically, the internal carotid arteries become narrowed or blocked. The result is a reduction of blood flow that can cause damage (“ischemia”) to the brain. When this occurs, the brain adapts by developing an abnormal vascular network of fragile blood vessels at the base of the brain, serving as new pathways for blood to flow.

Because these newly formed blood vessels are weak, they often cannot supply enough blood flow to support brain function. For this reason, the condition may result in ischemic strokes, transient ischemic strokes (ministrokes), or hemorrhagic strokes (bleeding in the brain).

This rare disease, first discovered in Japan, is found in individuals throughout the world. In the Japanese language, the name moyamoya means “puff of smoke,” which describes the way the tiny blood vessels appear on radiologic imaging.

The U-M Health Comprehensive Moyamoya Program

Early recognition and evaluation of symptoms by an experienced team is critical for an accurate diagnosis and treatment of moyamoya disease. The University of Michigan Health Comprehensive Moyamoya Program brings together a collaborative team of neurologists, neurosurgeons, neuroradiologists and other specialists to provide an unparalleled experience in the diagnosis and treatment of moyamoya disease. Learn more about our approach to treatment below.

Who Gets Moyamoya Disease?

Moyamoya disease is very rare. There are genetic forms of moyamoya that occur most commonly in patients of Asian ancestry, but the disease is being diagnosed more and more in patients of all ethnicities. For reasons unknown, moyamoya disease is two times more common in patients assigned female at birth compared to those assigned male at birth.

There are two age ranges in which moyamoya commonly presents, although this disease can present at any age. Children are usually diagnosed between the ages of 5 and 10 while adults are often diagnosed between the ages of 30 and 50.

Symptoms of Moyamoya Disease

The first signs of moyamoya disease are often typical stroke symptoms such as:

• Facial asymmetry
• Weakness on one side of the body
• Difficulty speaking or understanding words
• Sensation changes on one side of the body

These symptoms often prompt urgent evaluation by a healthcare provider and a stroke workup where the abnormal blood vessel pattern of moyamoya is noted on CT or MR imaging.

Other symptoms may include seizures, headaches, involuntary movements, or progressive difficulty in thinking or memory.

Diagnosing Moyamoya Disease

Advanced imaging techniques may be performed based on a patient’s symptoms and history. These may include:

• MRI: Uses a magnetic field and radiofrequency waves to create a detailed picture of the brain and blood vessels.
• Cerebral angiogram: Uses an X-ray and contrast dye administered by catheter to produce an image of blood vessels of the head and neck.
• Computed tomography (CT) scan: An X-ray imaging technique to view blood vessels in the brain.
• Electroencephalogram (EEG): A test used to evaluate electrical activity in the brain that can help diagnosis seizures or a likelihood to have seizures.
• Transcranial doppler ultrasound: A test that uses sound waves to detect issues with blood flow in the brain.

Treatments for Moyamoya Disease

There is currently no cure for moyamoya disease. The goal of treatment is to prevent damage to the brain. A patient’s individualized treatment plan depends on several factors, including the degree of blood vessel narrowing and the overall pattern of blood flow in the brain. Treatments include:

Medications: For some patients, medications may be prescribed to manage symptoms such as high blood pressure, headaches, and seizures, as well as to reduce the risk of additional strokes.

Surgery: For patients who qualify, revascularization surgery to bypass blocked arteries can be beneficial. For these patients, revascularization surgery can also reduce the chance of future strokes.

There are two types of surgical procedures: direct revascularization and indirect revascularization.

• Direct revascularization surgery: This bypass procedure provides immediate new blood flow to the brain. The moyamoya blockages are bypassed by connecting a scalp artery to an artery on the surface of the brain to restore blood flow.
• Indirect revascularization surgery: This procedure involves placing an artery near the surface of the brain to enable blood vessels to eventually grow into and connect with other brain blood vessels, typically over the course of months after surgery.

Our Approach to Treating Patients with Moyamoya Disease

U-M Health’s highly skilled multidisciplinary team ensures each patient receives the best possible treatment for their individual condition. Heading up our team are neurosurgeons who have undergone world-class training in sophisticated revascularization techniques, making them some of the most experienced in the world in direct and indirect bypass surgery for patients with moyamoya disease.

Each patient case is approached comprehensively to determine the best course of treatment that aligns with each patient’s goals of care. Whether managed medically or with surgical revascularization, each patient is followed by our multidisciplinary team throughout their life to ensure continued optimal vessel health and management of any moyamoya comorbidities.

Pediatric moyamoya patients at U-M Health can seamlessly transition into our robust adult program, which is recognized by physicians throughout the world.

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