Moyamoya is a rare cerebrovascular disease characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. We report on the progression of the disease in a 3-year-old boy, confirmed to have idiopathic Moyamoya disease, over 6 ensuing years, using serial magnetic resonance imaging with MR angiography. Comparison is also made with conventional angiography at the last visit. Characteristic imaging appearances of asymmetric narrowing of the internal carotid arteries (especially the supra-clinoid portion) with numerous collateral vessels around the brainstem especially within the ambient and quadrigeminal plate cisterns are demonstrated with progression.

moyamoya disease; idiopathic moyamoya; moyamoya disease progression; MRI; MRA