A provocative internal carotid artery balloon occlusion test with 99mTc-HM-PAO CBF mapping--report of three cases.

The balloon occlusion test (BOT) of the internal carotid artery (ICA), combined with induced hypotension and cerebral blood flow (CBF) mapping, was carried out in three patients with a large or giant aneurysm of the ICA. Occlusion of the ICA for 10 minutes in the normotensive state was followed by 5 minutes of induced hypotension. During the last 2 minutes of hypotensive occlusion, technetium-99m-hexamethyl-propyleneamine oxime was administered to study the CBF. All patients tolerated the procedure well. One patient with moderate CBF reduction developed ischemic complications 24 hours after permanent ICA occlusion. Another showed no significant change in CBF and tolerated permanent ICA occlusion well, while the third refused permanent occlusion. The provocative BOT combined with CBF mapping is a promising predictor of complications of ICA occlusion secondary to perfusion abnormalities.