Diagnosis of moyamoya disease primarily depends on the angiographic demonstration of stenosis and occlusion of the carotid bifurcation, and extensive parenchymal and leptomeningeal collaterals. According to previous reports, computed tomography (CT) reveals multiple low density areas in the brain, with atrophic changes. Based on this review of six cases, CT with contrast enhancement often reveals tortuous, curvilinear vessels in the basal ganglia, corresponding to extensive parenchymal and leptomeningeal collaterals on angiography. The most proximal portions of the anterior and middle cerebral arteries are often poorly visualized. When multiple low density areas or subarachnoid hemorrhages are encountered on CT, these findings in the basal ganglia should be sought for differential diagnosis.