Hippocampal volume and glucose metabolism in temporal lobe epileptic foci.
OBJECTIVE
Reports conflict on the relation of glucose metabolism to hippocampal volume in temporal lobe foci. Previous studies usually have used side-side ratios rather than regional metabolic rates.


METHODS
We measured hippocampal volume and glucose metabolism in 37 patients with temporal epileptogenic zones identified by ictal video-EEG telemetry. Metabolic rates were normalized to global brain mean.


RESULTS
Both 18-fluoro-2-deoxyglucose-PET and volumetric MRI lateralized the epileptic focus determined by ictal video-EEG. There were significant correlations between left-right metabolic asymmetry and hippocampal formation volume left-right ratios. Comparisons between normalized metabolism and hippocampal formation volume, ignoring the side of the epileptic focus, showed significant relations between left hippocampal volume and left inferior lateral temporal metabolism, right hippocampus and right inferior mesial temporal, and left hippocampus and left inferior mesial temporal metabolism. In contrast, when normalized metabolism was compared with hippocampal volume in the epileptic focus, no relation was found.


CONCLUSIONS
Our study suggests that the relation between hippocampal volume and glucose metabolism breaks down in epileptic foci and that hypometabolism is not dependent on neuronal loss. It is consistent with data suggesting that hypometabolism is an independent predictor of surgical outcome.
Theodore
W H
WH
Clinical Epilepsy Section, Epilepsy Research Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bldg. 10, Room 5N-250, Bethesda, MD 20892-1408, USA. theodore@codon.nih.gov
Gaillard
W D
WD
De Carli
C
C
Bhatia
S
S
Hatta
J
J
D001921:Brain / Q000378:metabolism; D004569:Electroencephalography / Q000706:statistics & numerical data; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality; D005947:Glucose / Q000378:metabolism*; D006624:Hippocampus / Q000033:anatomy & histology* / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D011336:Probability; D013686:Telemetry; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000378:metabolism / Q000503:physiopathology*; D014055:Tomography, Emission-Computed / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014743:Videotape Recording
D019788:Fluorodeoxyglucose F18; D005947:Glucose