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28.03.2010
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A 26 year-old female with onset of an intractable . seizure disorder at 16 years of age. Seizures were characterized by complex motor behavior with no lateralizing features.

Correlation of MEG with Epileptic Substrate

CASE STUDY: Correlation of MEG with Epileptic Substrate

Physician: Robert Knowlton, M.D.,
University of California, San Francisco. Now at the University of Alabama, Birmingham.

Case study:
A 26 year-old female with onset of an intractable seizure disorder at 16 years of age. Seizures were characterized by complex motor behavior with no lateralizing features.
Scalp VEEG showed interictal spikes over left fronto-temporal region. Seizure activity was non-lateralizing.
Invasive VEEG was non-lateralizing.
MRI showed a small area of increased T2 signal in the left middle-temporal gyrus. 

 
FDG-PET showed focal relative hypometabolism in the left mid-llateral middle temporal gyrus. 

 

PET Hypometabolism
An MEG study was conducted using a 4-D Neuroimaging Magnes II 74-channel sensor configuration. MEG spike localizations showed a focal cluster adjacent and mesial to the MRI abnormality.
The agreement among MEG, MRI and FDG-PET was sufficient to send the patient to surgery, even though scalp and invasive VEEG were not definitive.
A lesionectomy and anterior lateral resection sparing mesial structures was performed. The pathology showed a ganglioglioma.
The patient had no residual deficits and was seizure-free after surgery. 

Conclusion:
The combination of non-invasive MEG and MRI with minimally-invasive FDG-PET was sufficient to define a surgical plan that rendered the patient seizure free, even though the scalp and invasive VEEG data were non-diagnostic.