[The responses of somatosensory evoked potentials and cerebral blood flow to acetazolamide in patients with occlusive carotid disease].

The correlation between somatosensory evoked potential (SEP) and regional cerebral blood flow (rCBF) changes after acetazolamide administration was studied in six patients presented with transient ischemic attack (TIA) or minor completed stroke. All patients had no or only localized low density area on computed tomography, and severe occlusive disease in the ipsilateral common or internal carotid artery on cerebral angiography. In two patients with internal carotid artery occlusion, both marked decrease in ipsilateral N20 amplitude and prolongation of ipsilateral N20 latency were observed from 5-10 minutes after acetazolamide injection. These changes gradually improved and resolved 30-45 minutes after acetazolamide injection. In these cases, stable xenon CT revealed paradoxical rCBF decrease in the territory of the ipsilateral middle cerebral artery after acetazolamide injection. Especially, rCBF in the ipsilateral centrum semiovale fell to less than 20 ml/100 g/min. The other patients showed no change in SEPs and no paradoxical decrease in rCBF after acetazolamide injection. These results suggest that SEP test with acetazolamide loading could be valuable to evaluate a certain group of the patients with severely disturbed cerebral perfusion reserve in the carotid territory and suitable candidate for extracranial-intracranial arterial bypass (EC/IC bypass), although further investigations is needed.