Prediction of seizure outcome following epilepsy surgery: asymmetry of thalamic glucose metabolism and cerebral neural activity in temporal lobe epilepsy.
OBJECTIVE
The objective of this retrospective study is to analyze whether preoperative functional imaging studies using FDG-PET and MEG enable prediction of postoperative seizure outcomes.


METHODS
Thirty-six patients with intractable temporal lobe epilepsy were studied. Asymmetry index of tCMRgluc (PET-AI) and the equivalent current dipole intensity of first response of SEF (SEF-AI) were determined preoperatively using (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetoencephalography (MEG), respectively. Seizure outcomes were evaluated according to the classification proposed by the International League Against Epilepsy (ILAE) at least 24 months after resection of epileptic focuses. Twelve healthy volunteers were included in this study to determine the normal value.


RESULTS
Quantitative analysis revealed mean PET-AI in the patients was 5.4+/-5.2% (significantly different from normal controls); mean SEF-AI was 25.2+/-20.6% (not significantly different). PET-AI was positive (indicative of epileptic focus) in 29 of 36 patients (80.6%), while SEF-AI was positive in 17 of 36 patients (47.2%). Although no significant correlation between PET-AI and SEF-AI was noted (r=0.43), concordant asymmetry in both PET-AI and SEF-AI was significantly associated with better seizure outcome than discordant or paradoxical asymmetry of both factors (p<0.01).


CONCLUSIONS
The results suggest that quantitative analysis of tCMRgluc with SEF may be helpful in characterizing the preoperative epileptogenic condition and predicting postoperative seizure outcome in patients with temporal lobe epilepsy, although a constellation of developmental brain abnormalities and environmental factors that together produce epilepsy need to be further explored.
Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan. s-sakamoto@med.osaka-cu.ac.jp
Shinichi
S
Sakamoto
Toshihiro
T
Takami
Naohiro
N
Tsuyuguchi
Michiharu
M
Morino
Kenji
K
Ohata
Yuichi
Y
Inoue
Wataru
W
Ide
Ikuo
I
Hashimoto
Hajime
H
Kamada
Hiroaki
H
Tanaka
Mitsuhiro
M
Hara
D000328:Adult; D002648:Child; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D011184:Postoperative Period; D011237:Predictive Value of Tests; D018709:Statistics, Nonparametric; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism*; D016896:Treatment Outcome; D055815:Young Adult
D019788:Fluorodeoxyglucose F18; D005947:Glucose