[Follow-up study of the giant aneurysm by CT scan after unilateal carotid ligation (author's transl)].

We report a rare case of giant aneurysm of the anterior communicating artery, which was followed up by CT scan after unilateral carotid ligation. A 50-year-old female visited our clinic complaining of headache and visual disturbance. Neurological examination revealed bitemporal hemianopsia and loss of visual acuity. A giant anterior communicating artery aneurysm was found on right carotid angiograms. After ligation of the right common carotid artery, the aneurysm was reduced in size. Three weeks later, however, it ruptured and the patient died two months later. Autopsy showed the ruptured dome of the aneurysm. The wall of the sac lacked elastic fibers. It was considered that after carotid ligation the wall of the dome was pressed directly by the remaining blood flow, and the aneurysmal rupture was caused. We should give care to the aneurysm after carotid ligation.