Cerebral metabolic changes (18F-FDG PET) during selective anterior temporal lobe amobarbital test

Cerebral glucose utilisation using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) was measured in 4 patients with temporal lobe epilepsy during a selective anterior temporal lobe (TL) amobarbital test (ATLAT) and compared with their baseline values. 18F-FDG was injected intravenously immediately after administration of amobarbital into the anterior choroidal artery (acha) in the case of the superselective ATLAT and into the territories of acha, posterior communicating artery, and ophthalmic artery in the case of the ATLAT using the temporary balloon occlusion technique. A decrease in glucose uptake as a result of amobarbital application was observed in ipsilateral temporolateral (4 patients), ipsilateral temporomesial (2 patients) and bilateral frontolateral (1 patient) cortices. All patients showed decreased glucose uptake in contralateral temporolateral regions. Cerebellar diaschisis was observed in 2 patients. In conclusion, although aimed at selective inactivation of the mesiobasal TL structures, the ATLAT does not result in exclusive selective glucose hypometabolism of these structures. Relatively widespread ipsilateral and contralateral effects were observed suggesting local and remote metabolic deafferentation. No association was observed between the glucose uptake, clinical or memory performance.