These authors contributed equally to this manuscript.
Full-Length Original Research
Ictal EEG-fMRI in localization of epileptogenic area in patients with refractory neocortical focal epilepsy
Version of Record online: 29 JUL 2013
Wiley Periodicals, Inc. © 2013 International League Against Epilepsy
Volume 54, Issue 9, pages 1688–1698, September 2013
How to Cite
Sierra-Marcos, A., Maestro, I., Falcón, C., Donaire, A., Setoain, J., Aparicio, J., Rumià, J., Pintor, L., Boget, T., Carreño, M. and Bargalló, N. (2013), Ictal EEG-fMRI in localization of epileptogenic area in patients with refractory neocortical focal epilepsy. Epilepsia, 54: 1688–1698. doi: 10.1111/epi.12329
- Issue online: 6 SEP 2013
- Version of Record online: 29 JUL 2013
- Manuscript Accepted: 24 JUN 2013
- Fondo de Investigación Sanitaria. Grant Number: PI 050052
- Fundació la Marató de TV3 Catalunya. Grant Number: PI 060910
- Functional imaging;
- EEG ;
- MRI ;
To evaluate the usefulness of ictal electroencephalography (EEG)–combined functional magnetic resonance imaging ( MRI) (EEG-fMRI) in localizing epileptogenic zone in refractory neocortical focal epilepsy.
From the EEG-fMRI database of our institution including 62 adult patients, 14 (age 18–46 years) experienced some ictal event during the test. Data were segmented into 10-s blocks, and the results were analyzed by contrasting each block to the contiguous 10-s block from the onset of seizure onward, in all cases. In seizures lasting >10 s (five cases), a supplementary analysis was performed, contrasting each block to a baseline condition, in the framework of the general linear model (GLM) of analysis. Regions of activations were compared to results from the different techniques performed during presurgical evaluation, such as SISCOM, positron emission tomography (PET), and invasive subdural EEG monitoring.
Regarding the structural MRI findings, nine cases presented some lesion, with blood oxygen level– dependent (BOLD) signal activation placed in the same location in eight of them (89%). SISCOM studies were performed in 11 patients; 5 were concordant with the increase in BOLD signal in a sublobar level, whereas in 3 cases the concordance was in a lobar level. Eleven patients underwent PET studies, being also concordant in a sublobar level in four of them and in a lobar level in four additional cases. Finally, invasive EEG evaluation was performed in three patients and all of them had the seizure-onset zone in the initial area of BOLD activation.
This study adds relevant information to support the integration of EEG-fMRI in the multidisciplinary presurgical workup in patients with refractory epilepsy.