FUNCTIONAL NEUROIMAGING WITH POSITRON EMISSION TOMOGRAPHY

Epilepsy research using positron emission tomography (PET) has provide d considerable new information about ictal and interictal dysfunctions in human epilepsy. Neuroreceptor mapping with PET ligands has reveale d altered central benzodiazepine receptor and opiate receptor densitie s in partial epilepsies interictally, and regional increases in endoge nous opioid peptide concentrations during absence seizures. Imaging of perfusion and glucose metabolism during cognitive processing has show n interictal abnormalities of regional activation in partial and gener alized epilepsies. The diagnostically robust patterns of interictal gl ucose hypometabolism are not adequately explained by macrostructural a nd microstructural alterations in temporal lobe epilepsy. Current inve stigations of the pathophysiology of interictal hypometabolism must ad dress ultrastructural and neurochemical factors. Clinical PET in pre s urgical evaluation of medically refractory epilepsies remains an activ e area of research, but remarkably little antiepileptic drug research has exploited PET techniques.