Page 204 - MEGIN Book Of Abstracts - 2023

Preoperative localization of seizure onset zones by can help in focusing implantation of icEEG electrodes
magnetic source imaging, EEG-correlated functional targeting the SOZ.
MRI, and their combination (2020)
Keywords: EEG-fMRI, MSI, icEEG, magnetic source imaging,
Berger, Assaf; Cohen, Noa; Fahoum, Firas; Medvedovsky, refractory epilepsy, seizure onset zone
Mordekhay; Meller, Aaron; Ekstein, Dana; Benifla, Mony;
Aizenstein, Orna; Fried, Itzhak; Gazit, Tomer; Strauss, Ido Journal of neurosurgery (2020), Vol. 134, No. 3 (32413858)
(2 citations)
Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv;
Hebrew University Hadassah Medical School, Jerusalem; and;
Rappaport Faculty of Medicine-Technion, Haifa, Israel Lateralization of epilepsy using intra-hemispheric
brain networks based on resting-state MEG data
OBJECTIVE Preoperative localization of seizure onset (2020)
zones (SOZs) is an evolving field in the treatment of re-
fractory epilepsy. Both magnetic source imaging (MSI), Pourmotabbed, Haatef; Wheless, James W; Babajani-
and the more recent EEG-correlated functional MRI Feremi, Abbas
(EEG-fMRI), have shown applicability in assisting surgi-
cal planning. The purpose of this study was to evaluate Neuroscience Institute & Le Bonheur Comprehensive Epilepsy
the capability of each method and their combination in Program, Le Bonheur Children's Hospital, Memphis, Ten-
localizing the seizure onset lobe (SL). nessee, USA; Department of Anatomy and Neurobiology,
University of Tennessee Health Science Center, Memphis,
METHODS The study included 14 patients who under- Tennessee, USA
went both MSI and EEG-fMRI before undergoing im-
plantation of intracranial EEG (icEEG) as part of the pre- ABSTRACT Focal epilepsy originates within networks
surgical planning of the resection of an epileptogenic in one hemisphere. However, previous studies have
zone (EZ) during the years 2012-2018. The estimated investigated network topologies for the entire brain. In
location of the SL by each method was compared with this study, magnetoencephalography (MEG) was used
the location determined by icEEG. Identification rates of to investigate functional intra-hemispheric networks
the SL were compared between the different methods. of healthy controls (HCs) and patients with left- or
right-hemispheric temporal lobe or temporal plus
RESULTS MSI and EEG-fMRI showed similar identifica- extra-temporal lobe epilepsy. 22 HCs, 25 left patients
tion rates of SL locations in relation to icEEG results (LPs), and 16 right patients (RPs) were enrolled. The
(88% ± 31% and 73% ± 42%, respectively; p = 0.281). debiased weighted phase lag index was used to calcu-
The additive use of the coverage lobes of both meth- late functional connectivity between 246 brain regions
ods correctly identified 100% of the SL, significantly in six frequency bands. Global efficiency, character-
higher than EEG-fMRI alone (p = 0.039) and nonsignifi- istic path length, and transitivity were computed for
cantly higher than MSI (p = 0.180). False-identification left and right intra-hemispheric networks. The right
rates of the additive coverage lobes were significantly global graph measures (GGMs) in the theta band were
higher than MSI (p = 0.026) and EEG-fMRI (p = 0.027). significantly different (p < .005) between RPs and both
The intersecting lobes of both methods showed the LPs and HCs. Right and left GGMs in higher frequency
lowest false identification rate (13% ± 6%, p = 0.01). bands were significantly different (p < .05) between
HCs and the patients. Right GGMs were used as input
CONCLUSIONS Both MSI and EEG-fMRI can assist in features of a Naïve-Bayes classifier to classify LPs and
the presurgical evaluation of patients with refractory RPs (78.0% accuracy) and all three groups (75.5% ac-
epilepsy. The additive use of both tests confers a high curacy). The complete theta band brain networks were
identification rate in finding the SL. This combination compared between LPs and RPs with network-based

 ontents  Index 183
C