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Ictal and interictal electric source imaging in pre-surgical evaluation: a prospective study

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  • P. Sharma, Danish Epilepsy Centre, Dianalund, King George's Medical University
  • ,
  • M. Scherg, BESA GmbH
  • ,
  • L. H. Pinborg, Rigshospitalet
  • ,
  • M. Fabricius, Rigshospitalet
  • ,
  • G. Rubboli, Danish Epilepsy Centre, Dianalund
  • ,
  • B. Pedersen, Danish Epilepsy Centre, Dianalund
  • ,
  • A. M. Leffers, Hvidovre Universitets Hospital, Hvidovre
  • ,
  • P. Uldall, Rigshospitalet
  • ,
  • B. Jespersen
  • J. Brennum, Rigshospitalet
  • ,
  • O. M. Henriksen, Rigshospitalet
  • ,
  • S. Beniczky

Background and purpose: Accurate localization of the epileptic focus is essential for surgical treatment of patients with drug-resistant epilepsy. Electric source imaging (ESI) is increasingly used in pre-surgical evaluation. However, most previous studies have analysed interictal (II) discharges. Prospective studies comparing the feasibility and accuracy of II and ictal (IC) ESI are lacking. Methods: We prospectively analysed long-term video-electroencephalography recordings (LTM) of patients admitted for pre-surgical evaluation. We performed ESI of II and IC signals using two methods, i.e. equivalent current dipole (ECD) and a distributed source model (DSM). LTM recordings employed the standard 25-electrode array (including inferior temporal electrodes). An age-matched template head model was used for source analysis. Results were compared with intracranial recordings, conventional neuroimaging methods [magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT)] and outcome at 1 year after surgery. Results: A total of 87 consecutive patients were analysed. ECD gave a significantly higher proportion of patients with localized focal abnormalities (94%) compared with MRI (70%), PET (66%) and SPECT (64%). Agreement between the ESI methods and intracranial recording was moderate to substantial (k = 0.56–0.79). A total of 54 patients were operated (47 patients more than 1 year ago) and 62% of them became seizure-free. The localization accuracy of II-ESI was 51% for DSM and 57% for ECD, and that for IC-ESI was 51% for DSM and 62% for ECD. The differences between the ESI methods were not significant. Differences in localization accuracy between ESI and MRI (55%), PET (33%) and SPECT (40%) were not significant. Conclusions: The II-ESI and IC-ESI of LTM data have high feasibility and their localization accuracy is similar to that of conventional neuroimaging methods.

Original languageEnglish
JournalEuropean Journal of Neurology
Pages (from-to)1154-1160
Number of pages7
Publication statusPublished - 1 Sep 2018

Bibliographical note

© 2018 EAN.

    Research areas

  • electric source imaging, epilepsy, long-term video-electroencephalography monitoring, pre-surgical evaluation, Neuroimaging, Prospective Studies, Electroencephalography/methods, Humans, Middle Aged, Tomography, Emission-Computed, Single-Photon, Epilepsy/diagnostic imaging, Male, Treatment Outcome, Positron-Emission Tomography, Young Adult, Magnetic Resonance Imaging, Seizures/diagnostic imaging, Adolescent, Brain Mapping, Adult, Female, Child, Preoperative Period

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