Moyamoya disease--imaging with magnetic resonance.

We report a case of moyamoya disease in a young adult female, in whom the initial clinical and radiological features were considered to be compatible with multiple sclerosis. The subsequent development of cerebral infarction led to the typical moyamoya features being found on carotid angiography. Magnetic resonance imaging (MRI) features of dilated collateral arteries were then recognized, and the initial MRI findings considered to represent demyelination were reinterpreted as areas of infarction. Although rare, moyamoya disease should be considered in the differential diagnosis in young patients presenting with symptoms and signs suggestive of multiple sclerosis. The diagnosis may be suggested by typical MRI findings.