Moyamoya syndrome: Pial synangiosis

Abstract

Moyamoya syndrome is an arteriopathy characterized by progressive stenosis at the apices of the intracranial internal carotid arteries associated with cerebral ischemia. As the internal carotids undergo this reduction in flow, the brain compensates through the development of smaller collateral vessels. This alternative blood supply provides circulation to the region formerly supplied by the internal carotids, and this fine network of vessels arises from the carotid apex, the leptomeninges, and branches of the external carotid artery supplying the dura and skull base. Although usually limited to the anterior circulation, there are rare cases where the process encompasses the posterior circulation as well, including the basilar and posterior cerebral arteries. The appearance of this collateral network on angiogram has been compared to a puffof smoke; in Japanese, moyamoya. © 2010 Springer-Verlag Tokyo.