NeuroradiologyMoyamoya disease
a progressive occlusive disease of the basal cerebral vessels forming the circle of Willis, of unknown aetiology. The clinical presentation is characterized by repeated ischaemic episodes in children and adolescents; the severity of the neurological deficits depends on the rapidity of progression, and the extent of the disease.
Progressive occlusion of the distal portion of the internal carotid arteries and of the proximal segments of the middle cerebral arteries is the angiographic hallmark of the disease together with a peculiar collateral circulation that involves meningeal vessels with transdural anastomosis and penetrating vessels of the basal ganglia. Hypertrophy of lenticulostriate arteries and thalamoperforating arteries leads to the characteristic appearance first described in the Japanese literature as the "puff of smoke" or Moyamoya. Although MR can show the infarcted areas of the brain the diagnostic modality of choice is cerebral angiography (Fig.1).
The angiographic pattern has been classified according to Suzuki et al., grading the severity from Stage I through Stage VI. Stage I represents narrowing of the internal carotid bifurcation and Stage VI reflects the appearance of the classical Moyamoya pattern with extensive pial collaterals through the external carotid arteries.
Adults may present with intraventricular and subarachnoid haemorrhage.
GS
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a, b. Lateral and AP right carotid angiogram. The supraclinoidal portion of the internal carotid artery is almost completely occluded. A very rich collateral network is seen involving the ophthalmic artery and pial collaterals. The anterior and middle cerebral artery are opacified via collaterals.
c, d. Selective left internal angiogram, lateral and AP view. A similar pattern is seen. The posterior circulation is vascularized through a persistent trigeminal artery.
e, f . Left vertebral artery. The same pattern is seen with hypertrophy of meningeal vessels and collaterals to supply the posterior cerebral arteries territory.
g, h. Selective right external carotid artery. The pial collateral circulation is extremely developed. Anterior and middle cerebral arteries are opacified via pial collaterals.
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Moyamoya disease, Fig.1 (a) | | Moyamoya disease, Fig.1 (b) | | Moyamoya disease, Fig.1 (c) |
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Moyamoya disease, Fig.1 (d) | | Moyamoya disease, Fig.1 (e) | | Moyamoya disease, Fig.1 (f) |
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Moyamoya disease, Fig.1 (g) | | Moyamoya disease, Fig.1 (h) | |