title: [Obstruction of the circle of Willis].
mesh_terms: D000293:Adolescent; D000328:Adult; D002533:Cerebral Angiography; D002539:Cerebral Arterial Diseases / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002941:Circle of Willis; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D008875:Middle Aged