Abstract
Diagnosis of moyamoya diseases primarily depends on the angiographic demonstration of stenosis and/orocclusion of internal carotid bifurcation, and extensive collaterals. Nine patients with moyamoya disease were studied with high resolution computed tomography(HRCT), and the CT findings were retrospectively analyzed. The CT scans revealed not only parenchymal ischemic and hemorrhagic changes, but also mottled, tortuous, linear, and/orthalamic regions, corresponding to extensive collaterals on angiography, in all nine patients. In addition, the circle of Willis was poorly or partly visualized in eight patients, which seems to reflect the vascular occlusionor stenosis. HRCT appears to play an improtant role in the diagnosis of moyamoya disease.