[F-18]FDG-PET and whole-scalp MEG localization of epileptogenic cortex

Purpose: To evaluate combined [F-18]fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET) and 122-channel whole-scalp magnetoencephalograph y (MEG) in lateralizing the epileptogenic cortex in patients whose routine presurgical evaluations gave discordant results about the location of the e pileptic focus. Methods: Nine patients (five women, four men) aged 13-40 years were studied . Subdural EEG (SEEG) was recorded from eight patients. Six patients were o perated on. Results: In seven of nine patients, PET and MEG agreed in localizing the ep ileptogenic cortex. When PET and MEG were in congruence, SEEG agreed with t he findings. In five of six operated-on patients, PET and MEG results were congruent, and the outcome of the operation was successful. Two patients ha d discordant PET and MEG results. In one patient, PET showed bitemporal hyp ometabolism, whereas MEG showed epileptiform activity in the right parietal lobe. The surgical outcome of the palliative temporal lobectomy was poor. Another patient had unilateral temporal hypometabolism in PET and bitempora l activity in MEG. She was not operated on. Conclusions: In most patients, PET and MEG were congruent in locating the e pileptogenic cortex. Thus the combination of these techniques may provide u seful support for the localization of the seizure onset and reduce the need for invasive procedures.