Magnetic source imaging versus intracranial electroencephalogram in epilepsy surgery: A prospective study

Knowlton, Robert C.; Elgavish, Rotem A.; Howell, Jennifer; Blount, Jeffrey P.; Burneo, Jorge G.; Faught, Edward; Kankirawatana, Pongkiat; Riley, Kristen; Morawetz, Richard B.; Worthington, Julie; Kuzniecky, Ruben

doi:10.1002/ana.20857

Cited by 160 publications

(124 citation statements)

References 31 publications

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“…Thus, our presurgical approach may potentially replace invasive monitoring for seizure localization in many patients with TSC. 12 This study also shows that younger age at surgery and shorter seizure duration was associated with higher rate of seizure freedom after surgery. Conversely, longer seizure duration was associated with lower rate of seizure freedom after surgery.…”

supporting

confidence: 57%

“…For this study, dipole clusters were defined as 5 or more epileptiform dipoles in 1 or contiguous sublobar regions of the brain. 12 By chance, patients 5 and 16 had seizures during their magnetoencephalography (MEG) studies (table 1), and the ictal onset zone closely matched the region localized by the interictal dipoles in the same study. Whereas 1 patient who had MSI elected not to undergo surgery, the other 13 children underwent surgery, with the final resection based on all noninvasive tests, and the intraoperative electrocorticography.…”

mentioning

confidence: 77%

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Noninvasive testing, early surgery, and seizure freedom in tuberous sclerosis complex

Wu¹,

Salamon²,

Kirsch³

et al. 2010

Neurology

113

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supporting

confidence: 57%

mentioning

confidence: 77%

Noninvasive testing, early surgery, and seizure freedom in tuberous sclerosis complex

Wu¹,

Salamon²,

Kirsch³

et al. 2010

Neurology

113

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“…A loose cluster was defined by five or more dipoles located within one sublobar region. Sublobar regions were defined using a common classification scheme (frontopolar, superior frontal, inferior frontal, mesial frontal, superior parietal, inferior parietal, mesial parietal, lateral occipital, mesial occipital, temporopolar, lateral temporal, and mesial temporal) (Knowlton et al, 2006;Schneider et al, 2012). A scattered cluster was defined by five or more dipoles involving more than one sublobar region.…”

Section: Definition Of Cluster Tightness and Orientationmentioning

confidence: 99%

“…Key advantages of MEG include non-invasiveness, high temporal and spatial resolution, and an ability to provide a broad whole-head view of brain activities. In many studies, MEG has been demonstrated to add non-redundant information to guide implantation sites for intracranial recordings (Knowlton et al, 2006;AgirreArrizubieta et al, 2014), resulting in changes to surgical treatment and medical management (Sutherling et al, 2008;Ito et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Correlating magnetoencephalography to stereo-electroencephalography in patients undergoing epilepsy surgery

Murakami

Wang

Marashly

et al. 2016

Brain

135

103

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) for a scientific commentary on this article.Magnetoencephalography and stereo-electroencephalography are often necessary in the course of the non-invasive and invasive presurgical evaluation of challenging patients with medically intractable focal epilepsies. In this study, we aim to examine the significance of magnetoencephalography dipole clusters and their relationship to stereo-electroencephalography findings, area of surgical resection, and seizure outcome. We also aim to define the positive and negative predictors based on magnetoencephalography dipole cluster characteristics pertaining to seizure-freedom. Included in this retrospective study were a consecutive series of 50 patients who underwent magnetoencephalography and stereo-electroencephalography at the Cleveland Clinic Epilepsy Center. Interictal magnetoencephalography localization was performed using a single equivalent current dipole model. Magnetoencephalography dipole clusters were classified based on tightness and orientation criteria. Magnetoencephalography dipole clusters, stereo-electroencephalography findings and area of resection were reconstructed and examined in the same space using the patient's own magnetic resonance imaging scan. Seizure outcomes at 1 year postoperative were dichotomized into seizurefree or not seizure-free. We found that patients in whom the magnetoencephalography clusters were completely resected had a much higher chance of seizure-freedom compared to the partial and no resection groups (P = 0.007). Furthermore, patients had a significantly higher chance of being seizure-free when stereo-electroencephalography completely sampled the area identified by magnetoencephalography as compared to those with incomplete or no sampling of magnetoencephalography results (P = 0.012). Partial concordance between magnetoencephalography and interictal or ictal stereo-electroencephalography was associated with a much lower chance of seizure freedom as compared to the concordant group (P = 0.0075). Patients with one single tight cluster on magnetoencephalography were more likely to become seizure-free compared to patients with a tight cluster plus scatter (P = 0.0049) or patients with loose clusters (P = 0.018). Patients whose magnetoencephalography clusters had a stable orientation perpendicular to the nearest major sulcus had a better chance of seizure-freedom as compared to other orientations (P = 0.042). Our data demonstrate that stereo-electroencephalography exploration and subsequent resection are more likely to succeed, when guided by positive magnetoencephalography findings. As a corollary, magnetoencephalography clusters should not be ignored when planning the stereo-electroencephalography strategy. Magnetoencephalography tight cluster and stable orientation are positive predictors for a good seizure outcome after resective surgery, whereas the presence of scattered sources diminishes the probability of favourable outcomes. The concordance pattern between magnetoencephalography and stereo-electroencephalography is a strong...

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“…Several studies have shown that this method can provide reliable and useful information in presurgical patients with partial epilepsy (Stefan et al, 2003;Wu et al, 2006;RamachandranNair et al, 2007), and have concluded that non-invasive MEG techniques might eventually partly replace invasive intracranial recording techniques (Pataraia et al, 2004;Papanicolaou et al, 2005;Knowlton et al, 2006). However, the analysis procedures require that each dipole is manually reviewed and classified as either corresponding to a real spike or as corresponding to a non-epileptic origin, which can be timeconsuming, requires trained and experienced scorers, and introduces a sizeable amount of subjectivity in the results.…”

Section: Introductionmentioning

confidence: 99%

Fast oscillations associated with interictal spikes localize the epileptogenic zone in patients with partial epilepsy

et al. 2008

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Although interictal epileptic spikes are defined as fast transient activity, the spatial distribution of spike-related high-frequency power changes is unknown. In this study, we localized the sources of spike-locked power increases in the beta and gamma band with magnetoencephalography and an adaptive spatial filtering technique, and tested the usefulness of these reconstructions for determining the epileptogenic zone in a population of 27 consecutive presurgical patients with medication refractory partial epilepsies. The reliability of this approach was compared to the performance of conventional MEG techniques such as equivalent current dipole (ECD) models. In patients with good surgical outcome after a mean follow up time of 16 months (Engel class I or II), the surgically resected area was identified with an accuracy of 85% by sources of spike-locked beta/gamma activity, which compared favourably with the accuracy of 69% found for ECD models of single spikes. In patients with a total of more than 50 spikes in their recordings, the accuracies increased to 100% vs. 88%, respectively. Imaging of spike-locked beta/gamma power changes therefore seems to be a reliable and fast alternative to conventional MEG techniques for localizing epileptogenic tissue, in particular if more than 50 interictal spikes can be recorded.

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Magnetic source imaging versus intracranial electroencephalogram in epilepsy surgery: A prospective study

Abstract: MSI yields localizing information with a high positive predictive value in epilepsy surgery candidates who typically require ICEEG. This finding suggests that enough clinical validity exists for MSI to potentially replace ICEEG for seizure localization.

Cited by 160 publications

References 31 publications

Noninvasive testing, early surgery, and seizure freedom in tuberous sclerosis complex

Noninvasive testing, early surgery, and seizure freedom in tuberous sclerosis complex

Correlating magnetoencephalography to stereo-electroencephalography in patients undergoing epilepsy surgery

Fast oscillations associated with interictal spikes localize the epileptogenic zone in patients with partial epilepsy

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