“Swimming Worms in a Bare Cistern”: A Sign for Moyamoya Disease

Abstract

Moyamoya disease is a rare cerebrovascular occlusive disorder most often found among the Japanese. It is angiographically defined as a progressive steno-occlusion of the bilateral internal carotid arteries with characteristic abnormal vascular networks, so-called Moyamoya vessels, at the base of the brain. MRI is the initial investigation of choice and we describe an MRI sign to diagnose Moyamoya disease warranting digital subtraction angiography.