Ictal EEG Source Imaging for Presurgical Evaluation of Refractory Focal Epilepsy

Mohammad Ashfak Habib; Fatimah Ibrahim; Mas S Mohktar; Shahrul Bahyah Kamaruzzaman; Kartini Rahmat; Kheng Seang Lim

doi:10.1016/j.wneu.2015.10.096

Ictal EEG Source Imaging for Presurgical Evaluation of Refractory Focal Epilepsy

World Neurosurg. 2016 Apr:88:576-585. doi: 10.1016/j.wneu.2015.10.096. Epub 2015 Nov 5.

Authors

Mohammad Ashfak Habib¹, Fatimah Ibrahim², Mas S Mohktar³, Shahrul Bahyah Kamaruzzaman⁴, Kartini Rahmat⁵, Kheng Seang Lim⁴

Affiliations

¹ Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia; Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia; Department of Computer Science & Engineering, Chittagong University of Engineering & Technology, Chittagong, Bangladesh.
² Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia; Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia. Electronic address: fatimah@um.edu.my.
³ Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia; Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia.
⁴ Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia; Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
⁵ Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.

PMID: 26548833
DOI: 10.1016/j.wneu.2015.10.096

Abstract

Background: Electroencephalography source imaging (ESI) is a promising tool for localizing the cortical sources of both ictal and interictal epileptic activities. Many studies have shown the clinical usefulness of interictal ESI, but very few have investigated the utility of ictal ESI. The aim of this article is to examine the clinical usefulness of ictal ESI for epileptic focus localization in patients with refractory focal epilepsy, especially extratemporal lobe epilepsy.

Methods: Both ictal and interictal ESI were performed by the use of patient-specific realistic forward models and 3 different linear distributed inverse models. Lateralization as well as concordance between ESI-estimated focuses and single-photon emission computed tomography (SPECT) focuses were assessed.

Results: All the ESI focuses (both ictal and interictal) were found lateralized to the same hemisphere as ictal SPECT focuses. Lateralization results also were in agreement with the lesion sides as visualized on magnetic resonance imaging. Ictal ESI results, obtained from the best-performing inverse model, were fully concordant with the same cortical lobe as SPECT focuses, whereas the corresponding concordance rate is 87.50% in case of interictal ESI.

Conclusions: Our findings show that ictal ESI gives fully lateralized and highly concordant results with ictal SPECT and may provide a cost-effective substitute for ictal SPECT.

Keywords: Epilepsy; Ictal EEG; Interictal EEG; Source imaging; Source localization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Brain Mapping / methods*
Child
Drug Resistant Epilepsy / diagnosis*
Drug Resistant Epilepsy / surgery*
Electroencephalography / methods*
Female
Humans
Male
Middle Aged
Preoperative Care / methods*
Reproducibility of Results
Retrospective Studies
Sensitivity and Specificity
Surgery, Computer-Assisted / methods*
Young Adult