Authors :
Presenting Author: Yasuyoshi Hiramatsu, MD – Hokkaido University Graduate School of Medicine
Midori Nakajima, M.D. Ph.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Fumiya Takeuchi, Ph.D. – Department of Clinical Engineering – Japan Healthcare University; Takeru Goto, M.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Shuhei Kimura, M.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Sachiko Nakakubo, M.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Masashi Narugami, M.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Yuki Ueda, M.D. Ph.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Kiyoshi Egawa, M.D. Ph.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine; Hideaki Shiraishi, M.D. Ph.D. – Department of Pediatrics – Hokkaido University Graduate School of Medicine
Rationale:
We investigated whether advanced dynamic parametric mapping (AdSPM) could identify the seizure onset zone in MRI-negative FCD type II.
Methods:
We retrospectively analyzed four patients with intractable focal epilepsy with negative finding in initial 3T-MRI. All the patients underwent Video-EEG, magnetoencephalography (MEG), electrocorticogram (ECoG) or stereotactic EEG (SEEG), and resective surgery. Three of them were pathologically confirmed as FCD type II. In the other one patient, FCD type II lesion was identified on the repeated MRI and pathology after the recent surgery has not achieved yet. Advanced dynamic statistical parametric mapping (AdSPM) is a novel approach for MEG to identify epileptogenic zone.
1 In AdSPM, we analyzed each 100 msec segment of MEG spikes in the vicinity of equivalent current dipole (ECD). The area with highest threshold was defined as location of spike source.
1 We compared spatial congruence between seizure onset zone and (1) ECD cluster, and (2) Spike source in AdSPM. We also compared if spike source was included in the resection area.
Results:
Among three patients with pathologically confirmed FCD type II, two patients showed no ECD clusters. The other one patient had an ECD cluster distant from the seizure onset zone confirmed by ECoG. All of the three patients had spike sources localized the seizure onset zone and were resected with postsurgical seizure outcome of ILAE class I at mean of 7
±6.7 months. The other one patient without pathological confirmation, ECD cluster was distant from the FCD type II lesion identified by repeated MRI. Spike source localized the seizure onset zone on ECoG which was consistent with MRI lesion. The spike source was resected in this patient.Conclusions:
AdSPM could localize seizure onset zone in four patients with MRI negative FCD type II. AdSPM may have potential to neurophisiologically guide depth electrodes and IVEEG (SEEG) implantation in case MRI-negative FCD type II.
References:
1Nakajima M, et al. Advanced dynamic statistical parametric mapping with MEG in localizing epileptogenicity of the bottom of sulcus dysplasia. Clin Neurophysiol. 2018 Jun;129(6):1182-1191.
Funding: None