History and Definition

Abstract

Characteristically, cerebral angiograms in cases of moyamoya disease show stenosis or occlusion of the terminal portion of the internal carotid artery bilaterally. Moreover, in the vicinity of the base of the brain, abnormal net-like vessels can also often be seen bilaterally, showing differences in the degree of the vascular network on the left and right. Depending upon the individual case, angiographical abnormalities are seen in the defects of the middle and/or anterior cerebral arteries, and sometimes of all the main cerebral arteries including the posterior cerebral artery (Fig. 1).