Long-term Outcome of Surgically Treated Bottom of Sulcus FCD Identified by Advanced dSPM
Abstract number :
2.045
Submission category :
3. Neurophysiology / 3D. MEG
Year :
2023
Submission ID :
935
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Midori Nakajima, MD PhD – Hokkaido University Hospital
Hiroshi Otsubo, M.D. – Professot, Department of Pediatrics, The Hospital for Sick Children,Toronto; Hideaki Shiraishi, M.D. Ph.D – Assistant Professor, Department of Pediatrics, Hokkaido University Hospital
Rationale:
This study aims to investigate long term surgical outcome of bottom of sulcus FCD (BOSD) identified by advanced dynamic statistical parametric mapping (AdSPM).
Methods:
We analyzed 15 children with intractable focal epilepsy with a diagnosis of FCD type II at the bottom of sulcus on 3T MRI. All children underwent scalp video EEG, MEG, intracranial video-EEG (IVEEG) and resective surgery. Advanced dynamic statistical parametric mapping (AdSPM), a novel approach for MEG to identify epileptogenic zone of bottom of sulcus dysplasia (Nakajima et al., 2018). We investigated long term surgical outcome of children with bottom of sulcus FCD type II identified by AdSPM. In AdSPM, we analyzed each 100 msec segment around MEG dipole estimated in single moving dipole (SMD) method. The area with highest threshold was defined as location of spike source. We compared spatial congruence between pathologically confirmed FCD type II and spike source in AdSPM, and their surgical outcomes. We defined “Localized” when spike source was localized seizure onset zone in ECoG.
Results:
Spike source localized the MRI lesion in 12 out of 15 children (80%). SMD cluster localized the MRI lesion in six out of 15 children (40%). All the 12 children localized by AdSPM underwent ECoG. Ten out of the 12 children (83%)had spike source localized within seizure onset zone. Eight out of the 10 children had pathological confirmation of FCD type II. Seven of the 8 children had surgical outcome of ILAE class 1 after mean of 5.1 years postoperatively. The other one child had ILAE class 3 due to residual lesion at the bottom of sulcus revealed in the postsurgical MRI.
Conclusions:
AdSPM had identified seizure onset zone in the BOSD in 83% of the children. Long term outcome of surgically treated BOSD identified by AdSPM showed excellent outcome except one case with residual lesion after the surgery. AdSPM may have potential of guiding placement of subdural grid electrodes for successful surgery with long term post-operative seizure freedom.
Funding: None
Neurophysiology