Regional cerebral blood flow during interictal state: differences between temporal lobe epilepsy and primary generalized epilepsy.

Regional cerebral blood flow (rCBF) was investigated during interictal state by 133Xenon intravenous clearance technique in two groups of epileptic patients: group I (n = 28) having partial complex seizures (temporal lobe epilepsy); group II (n = 14) having generalized seizures (primary generalized epilepsy). Mean hemispheric CBF was decreased in group I and unchanged in group II compared to normal controls. Modifications in rCBF pattern were observed in group I but not in group II. A marked hypoperfusion of one temporal region was found in patients from group I showing a unilateral and fixed epileptic focus. Hypoperfusion of other cerebral areas at a distance from the epileptic focus was greater for patients with a left epileptic focus than for those with a right epileptic focus. Patients with the same severity of disease and bilateral and variable foci had no significant modification of mean hemispheric CBF and rCBF distribution. These observations indicate that interictal investigations of rCBF may be of interest for a differential classification of epilepsy.