Comparison of [18F]FDG-PET, [99mTc]-HMPAO-SPECT, and [123I]-iomazenil-SPECT in localising the epileptogenic cortex.
OBJECTIVE
Firstly, to compare the findings of interictal 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and of single photon emission computed tomography (SPECT) using 99mTc-hexamethyl propylene-amine-oxime (HMPAO) and 123I-iomazenil in localising the epileptogenic cortex in patients who were candidates for epilepsy surgery, but in whom clinical findings, video EEG monitoring (V-EEG), MRI, and neuropsychological evaluations did not give any definite localisation of the seizure onset. Secondly, to assess the ability of these functional methods to help in the decision about the epilepsy surgery.


METHODS
Eighteen epileptic patients were studied with FDG-PET and iomazenil-SPECT. HMPAO-SPECT was performed in 11 of these 18 patients. Two references for localisation was used--ictal subdural EEG recordings (S-EEG) and the operated region.


RESULTS
Fifteen of 18 patients had localising findings in S-EEG. FDG-PET findings were in accordance with the references in 13 patients and iomazenil-SPECT in nine patients. HMPAO-SPECT visualised the focus less accurately than the two other methods. In three patients S-EEG showed independent bitemporal seizure onset. In these patients FDG-PET showed no lateralisation. However, iomazenil-SPECT showed temporal lobe lateralisation in two of them.


CONCLUSIONS
FDG-PET seemed to localise the epileptogenic cortex more accurately than interictal iomazenil-SPECT in patients with complicated focal epilepsy.
Lamusuo
S
S
Department of Neurology, University of Turku, Finland.
Ruottinen
H M
HM
Knuuti
J
J
Härkönen
R
R
Ruotsalainen
U
U
Bergman
J
J
Haaparanta
M
M
Solin
O
O
Mervaala
E
E
Nousiainen
U
U
Jääskeläinen
S
S
Ylinen
A
A
Kälviäinen
R
R
Rinne
J K
JK
Vapalahti
M
M
Rinne
J O
JO
D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000000981:diagnostic imaging / Q000473:pathology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005442:Flumazenil / Q000031:analogs & derivatives*; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019690:Technetium Tc 99m Exametazime; D005442:Flumazenil; C063038:iomazenil; D005947:Glucose