Cerebral Angiography in Moyamoya Syndrome Secondary to Vasculopathy in Down Syndrome

Moyamoya disease (MMD) is an idiopathic intracranial vasculopathy characterized by progressive bilateral stenosis or occlusion of the terminal internal carotid arteries (ICA) and their main branches with compensatory collateral angiogenesis. It is more prevalent among Asian populations and has a typical angiographic appearance. A similar angiographic pattern is associated with vasculopathy due to several medical conditions including Down syndrome and is termed Moyamoya syndrome [1].

A 29-year-old non-Asian woman with Down syndrome was presented with acute headache, transient visual loss, and transient confusion for two days prior to admission. MRI confirmed acute infarction in the left middle cerebral artery (MCA) territory, mainly in the left parietal lobe. CT angiography suggested bilateral MCA stenosis and near occlusion, and asymmetric vascular blush. Diagnostic cerebral angiography confirmed MMS pattern with high grade focal stenosis of M1 segment of left MCA (Figure 1), and near occlusion of proximal M1 segment of right MCA with reconstitution via collateral arteries, and prominence of the lenticulostriate perforating vessels with significantly reduced capillary filling distally (Figure 2). Collateral circulation was from leptomeningeal vessels from the posterior cerebral artery filling the temporal and parietal lobes. There was sparing of the terminal ICAs, the external carotid artery branches, and posterior circulation suggesting an early stage disease. At 4 months follow up, there was no recurrence of symptoms after three months of dual antiplatelet therapy (Aspirin 325 mg and Clopidogrel 75 mg daily) following by single antiplatelet. At nine months, a follow-up MRI brain showed new lacunar infarct in the right medial frontal lobe white matter. Patients did not develop new neurological deficits.