Subcortical [18F]fluorodeoxyglucose uptake in lesional epilepsy in patients with intracranial tumour.
BACKGROUND
We hypothesized that in patients with intracerebral tumours a subcortical metabolical shift may be present when the underlying pathology can, itself, be the epileptogenic focus. We also assumed that by studying the alterations in glucose metabolism beyond the tumour's borders we could identify a modulator area.


METHODS
Sixty-seven patients with supratentorial brain tumour associated epilepsy were investigated interictally, in normoglycaemic conditions, by using [18F]fluorodeoxyglucose positron emission tomography (FDG PET). The studies were analysed semiquantitatively by calculating standardized uptake values and asymmetry indices. Normal subjects and patients with non-epileptic brain lesions were used as controls.


RESULTS
Compared to normal controls frontal and temporal tumours showed significant changes in thalamic FDG uptake, which reflected hypometabolism of the affected side. It was noted in occipito-medial cortex in temporal tumours and in lentiform nucleus in frontal tumours as well. Comparison to lesional brains only proved that there was significant hypometabolism in lentiform nucleus in temporal tumours.


CONCLUSIONS
The quantified values obviously reflect biological changes. The observed subcortical hypometabolism is most likely secondary to underlying pathology. Although seizures in tumorous patients do not originate from subcortical structures their influence on cortical sites of seizure initiation could be explained by defective subcortical regulation of cortical excitability.
Novak
Laszlo
L
Department of Neurosurgery, Health and Life Sciences Center, University of Debrecen, Hungary. lnovak@jaguar.dote.hu
Emri
Miklos
M
Molnar
Peter
P
Balkay
Laszlo
L
Lengyel
Zsolt
Z
Tron
Lajos
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D001931:Brain Mapping; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000209:etiology / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005625:Frontal Lobe / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015173:Supratentorial Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism; D013702:Temporal Lobe / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18