Moyamoya syndrome

A 70 years-old man, with significant atherosclerotic risk factors, presented with acute onset of dysarthria, left-side facial paresthesias and hypotony of the left upper extremity. A non-contrast head CT showed a right basal ganglia hemorrhage and hyperdense ipsilateral MCA with a calcified atherosclerotic plaque. CT angiography of the cerebral arteries was performed demonstrating an occlusion of the right MCA with net-like collaterals. His angiogram confirmed the occlusion of the right MCA, with associated moyamoya collaterals.

Moyamoya disease is a cerebrovascular disorder, characterized by progressive steno-oclussive disease involving the main intracranial arteries, with secondary collateralization. The term moyamoya disease should be reserved for an idiopathic condition, However, this phenomenon can be seen in association with other diseases (atherosclerosis, radiation induced vasculopathy, phakomatoses, tuberculous meningitis, Graves disease, Down syndrome…), in which case the term moyamoya syndrome or pattern is used. The presentation depends on the age. In children, hemispheric ischemic strokes, ischemic strokes are the most frequent, whereas in adults hemorrhage or watershed infarcts are more common. Conventional angiography is useful to display the radiographic features: stenosis or occlusion of the arteries of the circle of Willis, as well as the development of collateral vascular network (puff of smoke). CTA and MRA are not always able to demonstrate this appearance on account of lower flow and spatial resolution.

Moyamoya disease is an idiopathic progressive vasculo-occlusive disease, most common in Asian population, nevertheless there are several entities that could mimic its features, causing a cerebrovascular accident.

- Acker G, Goerdes S, Schneider UC, Schmiedek P, Czabanka M, Vajkoczy P. Distinct clinical and radiographic characteristics of moyamoya disease amongst European Caucasians. European Journal of Neurology. 2015,22(6):1012–7. - Fujimura M, Tominaga T. Diagn