Original Article

Effect of epilepsy magnetic source imaging on intracranial electrode placement†

  1. Robert C. Knowlton MD, MSPH1,*,
  2. Shantanu N. Razdan MBBS2,
  3. Nita Limdi PhD, MSPH1,
  4. Rotem A. Elgavish MD, PhD1,
  5. Jeff Killen RT(MR)1,
  6. Jeffrey Blount MD3,
  7. Jorge G. Burneo MD, MSPH4,
  8. Lawrence Ver Hoef MD1,
  9. Lebron Paige MD1,
  10. Edward Faught MD1,
  11. Pongkiat Kankirawatana MD4,
  12. Al Bartolucci PhD2,
  13. Kristen Riley MD5,
  14. Ruben Kuzniecky MD6

Article first published online: 20 MAR 2009

DOI: 10.1002/ana.21660

Issue

Annals of Neurology

Annals of Neurology

Volume 65, Issue 6, pages 716–723, June 2009

Additional Information

How to Cite

Knowlton, R. C., Razdan, S. N., Limdi, N., Elgavish, R. A., Killen, J., Blount, J., Burneo, J. G., Ver Hoef, L., Paige, L., Faught, E., Kankirawatana, P., Bartolucci, A., Riley, K. and Kuzniecky, R. (2009), Effect of epilepsy magnetic source imaging on intracranial electrode placement. Annals of Neurology, 65: 716–723. doi: 10.1002/ana.21660

Author Information

  1. 1

    University of Alabama at Birmingham Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, School of Medicine

  2. 2

    University of Alabama at Birmingham School of Public Health, University of Alabama at Birmingham; Birmingham, AL

  3. 3

    Epilepsy Programme, Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada

  4. 4

    Division of Pediatric Neurology, Department of Pediatrics, University of Alabama at Birmingham School of Medicine; Birmingham, AL

  5. 5

    Division of Neurosurgery, Department of Surgery, University of Alabama at Birmingham School of Medicine; Birmingham, AL

  6. 6

    New York University Comprehensive Epilepsy Center, New York University Medical School, New York, NY

*UAB Epilepsy Center, 312 Civitan International Research Center, 1719 6th Avenue South, Birmingham, AL 35294-0001

  1. †

    Potential conflict of interest: Nothing to report.

Publication History

  1. Issue published online: 25 JUN 2009
  2. Article first published online: 20 MAR 2009
  3. Accepted manuscript online: 20 MAR 2009 12:00AM EST
  4. Manuscript Accepted: 23 JAN 2009
  5. Manuscript Revised: 19 DEC 2008
  6. Manuscript Received: 15 OCT 2008

Funded by

  • NIH (National Institute of Neurological Disorders and Stroke). Grant Number: K23 NS02218
  • Epilepsy Foundation of America Clinical Training and Research Fellowship

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Abstract

Objective

Intracranial electroencephalography (ICEEG) with chronically implanted electrodes is a costly invasive diagnostic procedure that remains necessary for a large proportion of patients who undergo evaluation for epilepsy surgery. This study was designed to evaluate whether magnetic source imaging (MSI), a noninvasive test based on magnetoencephalography source localization, can supplement ICEEG by affecting electrode placement to improve sampling of the seizure onset zone(s).

Methods

Of 298 consecutive epilepsy surgery candidates (between 2001 and 2006), 160 patients were prospectively enrolled by insufficient localization from seizure monitoring and magnetic resonance imaging results. Before presenting MSI results, decisions were made whether to proceed with ICEEG, and if so, where to place electrodes such that the hypothetical seizure-onset zone would be sampled. MSI results were then provided with allowance of changes to the original plan.

Results

MSI indicated additional electrode coverage in 18 of 77 (23%) ICEEG cases. In 39% (95% confidence interval, 16.4–61.4), seizure-onset ICEEG patterns involved the additional electrodes indicated by MSI. Sixty-two patients underwent surgical resection based on ICEEG recording of seizures. Highly localized MSI was significantly associated with seizure-free outcome (mean, 3.4 years; minimum, >1 year) for the entire surgical population (n = 62).

Interpretation

MSI spike localization increases the chance that the seizure-onset zone is sampled when patients undergo ICEEG for presurgical epilepsy evaluations. The clinical impact of this effect, improving diagnostic yield of ICEEG, should be considered in surgery candidates who do not have satisfactory indication of epilepsy localization from seizure semiology, electroencephalogram, and magnetic resonance imaging. Ann Neurol 2009;65:716–723

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