Metabolic changes of subcortical structures in intractable focal epilepsy.
OBJECTIVE
Intractable focal epilepsy is commonly associated with cortical glucose hypometabolism on interictal 2-deoxy-2[18F]-fluoro-D-glucose (FDG) positron emission tomography (PET). However, subcortical brain structures also may show hypometabolism on PET and volume changes on magnetic resonance imaging (MRI) studies, and these are less well understood in terms of their pathophysiology and clinical significance. In the present study, we analyzed alterations of glucose metabolism in subcortical nuclei and hippocampus by using FDG-PET in young patients with intractable epilepsy.


METHODS
Thirty-seven patients (mean age, 7.5 years; age range, 1-27 years) with intractable frontal (n = 23) and temporal (n = 14) lobe epilepsy underwent FDG-PET scanning as part of their presurgical evaluation. Normalized glucose metabolism was measured in the thalamus and caudate and lentiform nuclei, as well as in hippocampus, both ipsi- and contralateral to the epileptic focus, and correlated with duration and age at onset of epilepsy, presence or absence of secondary generalization, location of the epileptic focus, and extent of cortical glucose hypometabolism.


RESULTS
Long duration of epilepsy was associated with lower glucose metabolism in the ipsilateral thalamus and hippocampus. Duration of epilepsy was a significant predictor of ipsilateral thalamic glucose metabolism in both temporal and frontal lobe epilepsy. Presence of secondarily generalized seizures also was associated with lower normalized metabolism in the ipsilateral thalamus and hippocampus. Extent of cortical hypometabolism did not correlate with subcortical metabolism, and glucose metabolism in the caudate and lentiform nuclei did not show any correlation with the clinical variables.


CONCLUSIONS
The findings suggest that metabolic dysfunction of the thalamus ipsilateral to the seizure focus may become more severe with long-standing temporal and frontal lobe epilepsy, and also with secondary generalization of seizures.
Benedek
Krisztina
K
Department of Pediatrics, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Juhász
Csaba
C
Muzik
Otto
O
Chugani
Diane C
DC
Chugani
Harry T
HT
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D004828:Epilepsies, Partial / Q000000981:diagnostic imaging / Q000378:metabolism*; D017034:Epilepsy, Frontal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality; D005947:Glucose / Q000378:metabolism*; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D007223:Infant; D011300:Preoperative Care; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism; D014055:Tomography, Emission-Computed
D019788:Fluorodeoxyglucose F18; D005947:Glucose