The Adult Moyamoya Center

Moyamoya disease is a rare, chronic blood vessel (vascular) disorder in which the carotid artery in the skull becomes progressively narrowed or blocked, reducing blood flow to the brain.

In response to this reduced blood flow, a fragile network of blood vessels develops that on imaging studies resembles a puff of smoke (or “moyamoya” in Japanese). The reduced blood flow to the brain can eventually cause ischemic stroke (caused by a blood clot), hemorrhagic stroke (caused by a ruptured blood vessel) or seizures.

Moyamoya disease is often diagnosed in children, but more frequently it is being diagnosed in adults, often as young as their 30s and 40s. Women are more likely to develop the disease than men. As Moyamoya disease has become increasingly recognized in adults, it is now considered a cause of hemorrhage and stroke in adults.

Moyamoya disease was initially thought to be a disease largely of patients of Asian descent; however, it is now diagnosed in patients regardless of ethnicity.

The cause of Moyamoya disease is not known, although familial genetics appears to be a factor in about 10-15% of patients.

The symptoms depend on age. Children are likely to have transient ischemic attacks (TIAs) or mini-strokes. Adults with Moyamoya disease tend to suffer hemorrhagic strokes, which can recur, cause lasting damage and be fatal.

Symptoms of a brain hemorrhage can include:

• Nausea /vomiting
• Visual changes (the loss of vision in one eye, blurry vision)
• Severe headaches
• Numbness/tingling of the body
• Lethargy

Adults may also experience cognitive issues such as memory loss, confusion or poor motor skills.

If it is suspected that a patient has Moyamoya disease, our team of experts provides a comprehensive evaluation. The patient will undergo imaging studies, such as MRI/MRA and/or a CT angiography.  In addition, cerebral angiography will be performed.  After the completion of these studies, the patient will be evaluated by our team’s neurologist and one of our team’s neurosurgeons. 

Once this evaluation is completed, our team meets to review the information and determine the best course of treatment that will offer each patient the best possible outcomes.  The type of treatment will depend on a range of factors that are unique to each patient, from symptoms and the severity of the disease on imaging studies to the anticipated benefit of medical or surgical treatment.

Moyamoya disease may be managed with medicines (antiplatelets) and careful monitoring; however, because the disease will invariably worsen, many patients will require surgery to restore blood flow to the affected area of the brain (called revascularization surgery). This results in reduced incidence of hemorrhage and stroke.

At BIDMC, our highly experienced neurosurgeons offer two types of revascularization procedures: direct and indirect.

The direct procedure, called an extracranial to intracranial bypass procedure (EC-IC bypass), entails using a scalp artery to create a detour and immediately increase blood flow to the affected area of the brain.

The indirect bypass procedure, called Encephaloduroarteriosynangiosis (EDAS), results in the growth of new blood vessels to the affected area of the brain over the course of months. The effectiveness of both procedures are equivalent, however there is some evidence that EDAS may be safer.

The best time to treat Moyamoya disease is before the patient suffers a stroke, which may cause long-term damage and can be fatal. Any patient with symptoms consistent with Moyamoya disease should be evaluated by a multidisciplinary team of experienced Moyamoya specialists as soon as possible.