Pathological findings underlying focal temporal lobe hypometabolism in partial epilepsy
Source: Ann Neurol
1982 Dec;12(6):518-528.
Author: Engel J;Brown WJ;Kuhl DE;Phelps ME;Mazziotta JC;Crandall PH PubMed ID: 6984318
Abstract:
Histopathological studies were carried out on temporal lobe tissue
from 25 patients with partial complex seizures who were studied by
interictal positron computed tomography (PCT) with 18F-
fluorodeoxyglucose and subsequently underwent anterior temporal lobe
resection. Abnormalities were identified on x-ray computed tomographic
scans in 7 patients, but none indicated the site of a pathologically
confirmed structural lesion. Hypometabolic zones were observed on PCT
scans of 22 patients and corresponded to focal pathological
abnormalities in 19 (15 mesial temporal sclerosis, 2 small neoplasms, 1
angioma, 1 heterotopia). In 1 patient with a focally abnormal PCT scan
and no pathological changes, the lesion may have been located posterior
to the resection. In the remaining 2 patients, the hypometabolic zones
later disappeared and may have represented a transient response induced
by depth electrode implantation. Three patients with normal PCT scans
had no pathological abnormalities in their resected tissue. The degree
of relative hypometabolism measured by PCT correlated well with the
severity of the pathological lesion, but the size of the hypometabolic
zone was generally much larger than the area of pathological
involvement. This discrepancy could not be considered an artifact of
technique and must represent either structural abnormalities below the
resolution of routine histopathological studies (e.g., loss of synapses)
or functional inactivation of neuronal elements associated with the
epileptogenic lesion.