High-resolution MR technique can distinguish moyamoya disease from atherosclerotic occlusion

Moyamoya disease (MMD) is an idiopathic progressive narrowing of distal internal carotid arteries and secondary development of small collaterals.1 The distinction between MMD and intracranial atherosclerosis is not easy when a patient has concomitant vascular risk factors. We attempted to differentiate the 2 disease conditions by applying high-resolution plaque MRI in the occluded segment.2 High-resolution MRI of MMD disclosed blunted obliteration of the vessel lumen without eccentric plaque, and black-blood image delineated the occlusion site with homogeneous material and multiple spring-like vascular structures (figure, A). Intracranial atherosclerosis showed eccentric plaque with heterogeneous signals and enhancement (figure, B).