Metabolic correlates of epileptic spikes in cerebral cavernous angiomas.
BACKGROUND
Cerebral cavernous angiomas (CCA) are frequently associated with focal intractable epilepsy. Epileptogenicity is usually attributed to hemosiderin deposits. Combined recording of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) is a new method to investigate epileptic discharges.


METHODS
We used EEG-fMRI to identify BOLD responses to interictal spikes in patients with CCA. Responses were analyzed in the lesional and perilesional area, and at distance.


RESULTS
Eight patients were scanned, all with temporal lobe epilepsy and spikes. One patient had bilateral spikes, analyzed separately, and three studies with less than two spikes were excluded. All six studies analyzed showed BOLD responses. No response was found in the lesion itself or immediate periphery, and the raw fMRI signal showed signal loss in lesional and perilesional areas in all patients. Responses were close to the perilesional area in 2/6 studies. All patients showed responses at a distance from the lesions.


CONCLUSIONS
Despite susceptibility artifacts caused by iron deposits, we demonstrated EEG-fMRI responses involving the perilesional areas in 33% of studies. We also demonstrated diffuse rather than focal responses, in accordance with previous studies in lesional and non-lesional temporal lobe epilepsy, confirming the frequent distant effect of epileptic spikes.
Kobayashi
Eliane
E
Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal (PQ), Canada H3A 2B4. eliane.kobayashi@mcgill.ca
Bagshaw
Andrew P
AP
Gotman
Jean
J
Dubeau
François
F
D000328:Adult; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000150:complications / Q000503:physiopathology*; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006392:Hemangioma, Cavernous / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012640:Seizures / Q000209:etiology / Q000503:physiopathology*