Page 211 - MEGIN Book Of Abstracts - 2023

additional concordant diagnostic information to other ABSTRACT Deep-seated epileptic focus estimation us-
presurgical workup in another 2 patients; rejection ing magnetoencephalography is challenging because
of surgery in 3 patients originally deemed surgical of its low signal-to-noise ratio and the ambiguity of
candidates; change of plan from direct surgery to icEEG current sources estimated by interictal epileptiform
in 2 patients; and allowing icEEG in 3 patients deemed discharge (IED). We developed a distributed source
not surgical candidates. MSI results led to changed (DS) analysis method using a volume head model as
electrode locations and contact numbers in another 18 the source space of the forward model and standard-
patients. Epilepsy surgery was performed in 26 patients ized low-resolution brain electromagnetic tomogra-
influenced by MSI results and good surgical outcome phy combined with statistical methods (permutation
was achieved in 21 patients. tests between IEDs and baselines and false discovery
rate between voxels to reduce variation). We aimed to
CONCLUSIONS This prospective, blinded study showed evaluate the efficacy of the combined DS (cDS) analysis
that information provided by MSI allows more informed in surgical cases. In total, 19 surgical cases with adult
icEEG planning and surgical outcome in a significant and pediatric focal epilepsy were evaluated. Both cDS
percentage of patients with NLRFE and should be in- and equivalent current dipole (ECD) analyses were
cluded in the presurgical workup in those patients. performed in all cases. The concordance rates of the
two methods with surgically identified epileptic foci
Keywords: ATL = anterior temporal lobectomy, ECD = were calculated and compared with surgical outcomes.
equivalent current dipole, EMSI = electromagnetic source Concordance rates from the cDS analysis were signifi-
imaging, EZ = epileptogenic zone, MEG = magnetoen- cantly higher than those from the ECD analysis (68.4%
cephalography, MSI = magnetic source imaging, NLRFE = vs. 26.3%), especially in cases with deep-seated lesions,
nonlesional refractory focal epilepsy, SEEG = stereo-elec- such as in the interhemispheric, fronto-temporal
troencephalography, VEEG = video-EEG, epilepsy surgery, base, and mesial temporal structures (81.8% vs. 9.1%).
icEEG = intracranial EEG, magnetoencephalography, Furthermore, the concordance rate correlated well with
nonlesional, prospective study surgical outcomes. In conclusion, cDS analysis has bet-
ter diagnostic performance in focal epilepsy, especially
Neurosurgical focus (2020), Vol. 48, No. 4 (32234989) (9 with deep-seated epileptic focus, and potentially leads
citations) to good surgical outcomes.

Scientific reports (2020), Vol. 10, No. 1 (32210314) (0
Distributed source analysis of citations)
magnetoencephalography using a volume head
model combined with statistical methods improves
focus diagnosis in epilepsy surgery (2020) Interictal structural and functional connectivity
in idiopathic generalized epilepsy: A systematic
Ishizaki, Tomotaka; Maesawa, Satoshi; Nakatsubo, review of graph theoretical studies (2020)
Daisuke; Yamamoto, Hiroyuki; Takai, Sou; Shibata,
Masashi; Kato, Sachiko; Natsume, Jun; Hoshiyama, Pegg, Emily J; Taylor, Jason R; Keller, Simon S; Mohanraj,
Minoru; Wakabayashi, Toshihiko Rajiv

Department of Neurosurgery, Nagoya University Graduate Department of Neurology, Manchester Centre for Clinical
School of Medicine, Nagoya, Aichi, Japan. tomotakaishiza- Neurosciences, United Kingdom; Division of Neuroscience
[email protected]; Brain and Mind Research Center, Nagoya and Experimental Psychology, School of Biological Sciences,
University, Nagoya, Aichi, Japan; Department of Pediatrics, Faculty of Biology, Medicine and Health, University of Man-
Nagoya University Graduate School of Medicine, Nagoya, chester, United Kingdom. Electronic address: Emily-pegg@
Aichi, Japan doctors.org.uk; Division of Neuroscience and Experimental

 ontents  Index 190
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