Abstract
We report an adult patient with moyamoya disease which progressed from unilateral to bilateral involvement. The disease was detected with magnetic resonance angiography (MRA) and treated with a prophylactic direct revascularization. A 37-year-old female developed a cerebral infarction in the left frontal lobe. A MRA showed absence of a signal from the proximal portion of the left middle cerebral artery (MCA). A cerebral angiogram revealed obstruction of the terminal portion of the left middle cerebral artery(MCA). A cerebral angiogram revealed obstruction of the terminal portion of the left internal carotid artery (ICA) and basal moyamoya vessels. The right ICA did not have a steno-occlusive lesion. Because the diagnosis was 'probably'moyamoya disease, we performed direct bypass surgery on the affected left side. The result was an uneventful postoperative course. Follow-up MRA obtained 5 years after the first surgery showed the absence of a right MCA signal, although the patient did not have new symptoms. A cerebral angiogram demonstrated a steno-occlusive change at the terminal portion of the right ICA. Futhermore, a measurement of cerebral blood flow (CBF) gave a normal value at rest but a negative response to acetazolamide loading in the region of the right MCA. Direct bypass surgery was then performed on the right hemisphere to protect it from ischemic insult caused by a further progression of the moyamoya disease. A follow-up study revealed a rich revasculatization from the right external carotid artery, regression of the moyamoya vessels and an improvement of vascular reactivity. This case reinforces the necessity and usefulness of a follow-up MRA of adult patients with unilateral moyamoya disease. In cases where an impaired vascular reactivity is demonstrted in a CBF study, prophylactic revascularization may be considered.
