Moyamoya disease: diagnosis with three-dimensional time-of-flight MR angiography.

Twelve patients with moyamoya disease were studied with three-dimensional time-of-flight magnetic resonance (MR) angiography, and the findings were compared with results obtained with conventional arteriography. Of a total of 24 supraclinoid internal carotid arteries studied, 21 arteries (88%) were accurately evaluated with MR angiography and in three arteries the extent of occlusive disease was overestimated. Of a total of 72 large branch basal cerebral vessels, including the bilateral anterior, middle, and posterior cerebral arteries, 61 arteries (85%) were accurately evaluated with MR angiography and in 11 arteries the extent of occlusive disease was overestimated. While conventional arteriography showed basal cerebral moyamoya vessels in all 24 hemispheres, MR angiography showed moyamoya vessels in 20 of these. Of a total of 28 large leptomeningeal and transdural collateral vessels, 18 were identified with MR angiography. In the one surgical collateral vessel evaluated, MR angiography successfully showed its patency. MR angiography may have value in following disease progression and, perhaps, in evaluation of surgical bypass patency.