Figure 3: (a and b) Maximum intensity projection reconstructions in axial and coronal planes reveal uniform narrowing of the entire right internal carotid artery (from its origin till intracranial portion). Multiple small collateral vascular channels are seen at the apex of right internal carotid arteries with absence of A1 segment of right anterior cerebral artery and M1 segment of right middle cerebral artery. There is paucity of vessels in right cerebral hemisphere. Rest of the vessels of circle of Willis, left internal carotid arteries and vertero-basilar system appear normal in course and caliber