Optimizing Epileptogenic Zone Localization Using Magnetoencephalography (MEG)-guided Stereo-electroencephalography (sEEG) in Drug Resistant Epilepsy
Abstract number :
2.442
Submission category :
9. Surgery / 9B. Pediatrics
Year :
2024
Submission ID :
1067
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Negar Noorizadeh, PhD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital
Roozbeh Rezaie, PhD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital
Sarah Weatherspoon, MD – University of Tennessee Health Science Center
Amy Patterson, MD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital
Basanagoud Mudigoudar, MD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital
Paul Klimo, MD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital, St. Jude Children’s Research Hospital
Nir Shimony, MD – University of Tennessee Health Science Center
James Wheless, BScPharm, MD, FAAP, FACP, FAAN, FAES – LeBonheur Children’s Hospital
Shalini Narayana, PhD – University of Tennessee Health Science Center, Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital
Rationale: While stereo-electroencephalography (sEEG) is considered gold-standard for localizing the seizure onset zone (SOZ), characterization of the epileptogenic zone using this technique alone may be subject to spatial under sampling due to limited electrode coverage. To compensate for this, whole-head Magnetoencephalography (MEG) has been proposed as a complementary method in guiding sEEG electrode placement, based on non-invasive localization of interictal epileptiform discharges (IED) [1]. Although there is increasing evidence to support this in the adult population, the utility of MEG in guiding sEEG placement in pediatric epilepsy patients merits further investigation. To further explore the utility of MEG in guiding sEEG placement, we investigated the concordance between interictal epileptiform discharges identified by MEG (IEDMEG) with the IED and SOZ identified by sEEG (i.e., IEDsEEG and SOZsEEG) in patients with drug resistance epilepsy.
Methods: A retrospective chart review identified 12 subjects (mean age 11.9 years; range 4-25 years; with 75% being under 18 years) who underwent Phase I MEG and Phase II sEEG evaluation (Table 1). For each subject, IEDMEG, modeled as single equivalent current dipoles (ECD), were derived using visual inspection of the resting state recordings (mean duration 44 minutes; range 30-75 minutes). Determination of the IEDsEEG and SOZsEEG were based on an average of 6 days of continuous sEEG recordings (range 3-9 days). Co-registration of MEG dipole clusters and sEEG electrodes was performed to align them in a common native space (Figure 1), and the Euclidean distance between IEDMEG clusters and both IEDsEEG and SOZsEEG contacts was computed. IEDMEG clusters with at least one dipole within 10 mm of active sEEG contacts (i.e., IEDsEEG and SOZsEEG) were deemed as acceptable source locations.
Results: Among the 12 subjects analyzed, 19 IEDMEG clusters were localized. Six subjects had a single IEDMEG cluster, while the remaining 6 exhibited multifocal clusters. IEDsEEG and SOZsEEG were localized within 14 (74%) and 8 (42%) IEDMEG clusters, with average distances of 16.36 mm (range 6.15-26.74 mm) and 16.87 mm (range 6.05-26.80 mm), respectively. Additionally, 34% and 49% of IEDMEG clusters were within 10 mm of the IEDsEEG and SOZsEEG, respectively. In two patients, none of the IEDMEG clusters were within 10 mm of the IEDsEEG, and in four patients, none were within 10 mm of the and SOZsEEG.
Conclusions: The range of concordance reported in this study between MEG and sEEG, highlights the spatial sensitivity of the two methodologies, and emphasizes the complementary nature of the techniques in understanding the epileptogenic zone. In particular, the fact that MEG most readily characterizes the irritative zone and has broader spatial yield which may be of prognostic value, has the potential to further inform on sEEG placement, particularly in pediatric patients who comprised a majority of patients in this study.
References:
1. Murakami H, et al: Correlating magnetoencephalography to stereo-electroencephalography in patients undergoing epilepsy surgery. Brain 2016, 139(11):2935-2947.
Funding: NA
Surgery