HOUSTON – Combined electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) with electrical source imaging (ESI) is effective at identifying a single spatial target with high accuracy for use in epilepsy surgery. The study results were presented at the 2016 American Epilepsy Society Annual Meeting.1

EEG/fMRI and ESI have previously demonstrated usefulness alone and combined in mapping regions of brain activity and localization of a spatial target needed in order to perform resective epilepsy surgery.2-5 In this study, Maria Centeno, MD, of University College London, United Kingdom, and colleagues sought to assess and compare the localizing and predictive value of EEG/fMRI and ESI alone and combined in a cohort of pediatric patients with focal epilepsy.

Fifty-three pediatric patients with treatment-resistant epilepsy and frequent interictal epileptiform discharges (IEDs) were included in the study and underwent EEG/fMRI. Surgery was performed in 20 of those patients. Single localization was determined using a decision tree (available in the abstract). Once the epileptogenic focus was determined, accuracy measures predictive of surgery outcomes were compared between the combined method and EEG/fMRI or ESI alone.

Overall, 52 patients had significant results: 34 for combined EEG/fMRI and ESI; 13 for EEG/fMRI alone; and 5 for ESI alone. The combined method allowed for identification of a single localization in 47 of 53 patients, contributing to a more specific characterization of the epileptic focus in 64% of all patients and 82% of MRI-negative patients. Among the 19 patients who had significant results and underwent surgery, localization predicted surgery outcome with 100% sensitivity and 83% specificity. In comparison, EEG/fMRI alone and ESI alone demonstrated lower sensitivity and specificity (21%, 83% and 83%, 75%, respectively). Localization in 22 patients with concordant EEG/fMRI and ESI cluster predicted outcome with 100% sensitivity and specificity.

The authors concluded that the combined use of EEG/fMRI with ESI results in localization of the epileptic focus with a high degree of accuracy, noting that the approach is “particularly useful in providing a spatial hypothesis in MRI-negative cases.”

Disclosures: This study was supported by Action Medical Research.

Click here for more coverage of AES 2016.

Related Articles

References

  1. Centeno M, Perani S, Shamshiri E, et al. Better together? EEG-fMRI and ESI improve localization accuracy and predict surgical outcome in paediatric focal epilepsy. Presented at: 2016 American Epilepsy Society Annual Meeting; December 2-6, 2016; Houston, TX. Abstract 2.143.
  2. Centeno M, Carmichael DW. Network connectivity in epilepsy: resting state fMRI and EEG-fMRI contributions. Front Neurol. 2014;5:93.
  3. Brodbeck V, Spinelli L, Lascano AM, et al. Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain. 2011;134(Pt 10):2887-2897.
  4. Russo A, Jayakar P, Lallas M, et al. The diagnostic utility of 3D electroencephalography source imaging in pediatric epilepsy surgery. Epilepsia. 2016;57(1):24-31.
  5. Vulliemoz S, Lemieux L, Daunizeau J, Michel CM, Duncan JS. The combination of EEG source imaging and EEG-correlated functional MRI to map epileptic networks. Epilepsia. 2010;51(4):491-505.