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Updated: Jul 10, 2026
09:57
Electromagnetic Source Imaging in Presurgical Evaluation of Children with Drug-Resistant Epilepsy
Published on: September 20, 2024
Complementary predictive value of electromagnetic source imaging and hemodynamic responses in epilepsy surgery: A
Chifaou Abdallah1,2, Edouard Delaire3, Arielle Dascal1,2
1Montreal Neurological Institute and Hospital, McGill University, Montréal, Québec, Canada.
Epilepsia
|July 9, 2026
Summary
Electromagnetic source imaging (EMSI) and EEG/functional MRI (fMRI) offer complementary insights for epilepsy surgery. Concordant multimodal findings accurately predict good surgical outcomes in patients with drug-resistant focal epilepsy.
Area of Science:
- Neuroscience
- Medical Imaging
- Epileptology
Background:
- Accurate presurgical evaluation is crucial for defining the epileptogenic zone in focal epilepsy.
- Assessing the spatial extent of epileptic activity relative to the surgical cavity is key for successful outcomes.
- Electromagnetic source imaging (EMSI) and hemodynamic responses (fMRI) are potential tools for this assessment.
Purpose of the Study:
- To evaluate how EMSI and hemodynamic responses to epileptic discharges correlate with the surgical cavity and postoperative outcomes.
- To determine if multimodal concordance between EEG/magnetoencephalography (MEG) and EEG/fMRI improves surgical prediction accuracy.
- To compare the predictive performance of individual and combined imaging modalities.
Main Methods:
- Included consecutive patients with drug-resistant focal epilepsy undergoing EEG/MEG and EEG/fMRI, followed by surgery and at least 1-year follow-up.
- Quantified spatial concordance with the surgical cavity using spatial overlap (AUC), distance localization error (DLE), and spatial dispersion (SD).
- Evaluated predictive performance using a combined spatial criterion (AUC >0.70 and DLE = 0 mm).
Main Results:
- EEG/MEG showed higher spatial overlap and shorter DLE in patients with good postoperative outcomes (p<0.05).
- EEG/fMRI demonstrated similar trends, though not statistically significant.
- Multimodal analysis revealed that all patients with concordant resected findings achieved good outcomes, while discordant results predicted poor outcomes.
Conclusions:
- EEG/MEG and EEG/fMRI exhibit complementary roles in presurgical evaluation for epilepsy.
- Resection of EEG/MEG localizations correlated with better outcomes, while unresected EEG/fMRI responses predicted poorer outcomes.
- A quantitative, multimodal approach integrating concordant findings is recommended for improved presurgical evaluation and surgical outcome prediction.
