scholarly journals Preoperative localization of seizure onset zones by magnetic source imaging, EEG-correlated functional MRI, and their combination

2020 ◽  
pp. 1-7
Author(s):  
Assaf Berger ◽  
Noa Cohen ◽  
Firas Fahoum ◽  
Mordekhay Medvedovsky ◽  
Aaron Meller ◽  
...  
Keyword(s):  
Functional Mri ◽  
Refractory Epilepsy ◽  
Preoperative Localization ◽  
False Identification ◽  
Seizure Onset ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Identification Rate ◽  
Magnetic Source ◽  
Seizure Onset Zones

OBJECTIVEPreoperative localization of seizure onset zones (SOZs) is an evolving field in the treatment of refractory epilepsy. Both magnetic source imaging (MSI), and the more recent EEG-correlated functional MRI (EEG-fMRI), have shown applicability in assisting surgical planning. The purpose of this study was to evaluate the capability of each method and their combination in localizing the seizure onset lobe (SL).METHODSThe study included 14 patients who underwent both MSI and EEG-fMRI before undergoing implantation of intracranial EEG (icEEG) as part of the presurgical planning of the resection of an epileptogenic zone (EZ) during the years 2012–2018. The estimated location of the SL by each method was compared with the location determined by icEEG. Identification rates of the SL were compared between the different methods.RESULTSMSI and EEG-fMRI showed similar identification rates of SL locations in relation to icEEG results (88% ± 31% and 73% ± 42%, respectively; p = 0.281). The additive use of the coverage lobes of both methods correctly identified 100% of the SL, significantly higher than EEG-fMRI alone (p = 0.039) and nonsignificantly higher than MSI (p = 0.180). False-identification rates of the additive coverage lobes were significantly higher than MSI (p = 0.026) and EEG-fMRI (p = 0.027). The intersecting lobes of both methods showed the lowest false identification rate (13% ± 6%, p = 0.01).CONCLUSIONSBoth MSI and EEG-fMRI can assist in the presurgical evaluation of patients with refractory epilepsy. The additive use of both tests confers a high identification rate in finding the SL. This combination can help in focusing implantation of icEEG electrodes targeting the SOZ.

Magnetic source imaging (MSI) in the evaluation of patients with medically refractory epilepsy

1995 ◽  
Vol 95 (1) ◽  
pp. P9-P10
Author(s):  
M. Aung ◽  
B.J. Schwartz ◽  
D.F. Sobel ◽  
J.S. Ebersole ◽  
J.R. Smith ◽  
...  
Keyword(s):  
Refractory Epilepsy ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Magnetic Source ◽  
Medically Refractory Epilepsy

Accuracy of diffusion tensor magnetic resonance imaging tractography assessed using intraoperative subcortical stimulation mapping and magnetic source imaging

2007 ◽  
Vol 107 (3) ◽  
pp. 488-494 ◽  
Author(s):  
Jeffrey I. Berman ◽  
Mitchel S. Berger ◽  
Sungwon Chung ◽  
Srikantan S. Nagarajan ◽  
Roland G. Henry
Keyword(s):  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Fiber Tracking ◽  
Bipolar Electrode ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Motor Pathway ◽  
Magnetic Source ◽  
Subcortical Stimulation

Object Resecting brain tumors involves the risk of damaging the descending motor pathway. Diffusion tensor (DT)–imaged fiber tracking is a noninvasive magnetic resonance (MR) technique that can delineate the subcortical course of the motor pathway. The goal of this study was to use intraoperative subcortical stimulation mapping of the motor tract and magnetic source imaging to validate the utility of DT-imaged fiber tracking as a tool for presurgical planning. Methods Diffusion tensor-imaged fiber tracks of the motor tract were generated preoperatively in nine patients with gliomas. A mask of the resultant fiber tracks was overlaid on high-resolution T1- and T2-weighted anatomical MR images and used for stereotactic surgical navigation. Magnetic source imaging was performed in seven of the patients to identify functional somatosensory cortices. During resection, subcortical stimulation mapping of the motor pathway was performed within the white matter using a bipolar electrode. Results A total of 16 subcortical motor stimulations were stereotactically identified in nine patients. The mean distance between the stimulation sites and the DT-imaged fiber tracks was 8.7 ±3.1 mm (±standard deviation). The measured distance between subcortical stimulation sites and DT-imaged fiber tracks combines tracking technique errors and all errors encountered with stereotactic navigation. Conclusions Fiber tracks delineated using DT imaging can be used to identify the motor tract in deep white matter and define a safety margin around the tract.

scholarly journals Magnetic source imaging for the surgical evaluation of electroencephalography-confirmed secondary bilateral synchrony in intractable epilepsy

2009 ◽  
Vol 111 (6) ◽  
pp. 1248-1256 ◽  
Author(s):  
Edward F. Chang ◽  
Srikantan S. Nagarajan ◽  
Mary Mantle ◽  
Nicholas M. Barbaro ◽  
Heidi E. Kirsch
Keyword(s):  
Mr Imaging ◽  
Intractable Epilepsy ◽  
Focal Lesion ◽  
Seizure Type ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Ms Imaging ◽  
Epileptiform Discharges ◽  
Magnetic Source ◽  
Imaging Results

Object Routine scalp electroencephalography (EEG) cannot always distinguish whether generalized epileptiform discharges are the result of primary bilateral synchrony or secondary bilateral synchrony (SBS) from a focal origin; this is an important distinction because the latter may be amenable to resection. Whole-head magnetoencephalography (MEG) has superior spatial resolution compared with traditional EEG, and can potentially elucidate seizure foci in challenging epilepsy cases in which patients are undergoing evaluation for surgery. Methods Sixteen patients with medically intractable epilepsy in whom SBS was suspected were referred for magnetic source (MS) imaging. All patients had bilateral, synchronous, widespread, and most often generalized spike-wave discharges on scalp EEG studies, plus some other clinical (for example, seizure semiology) or MR imaging feature (for example, focal lesion) suggesting focal onset and hence possible surgical candidacy. The MS imaging modality is the combination of whole-head MEG and parametric reconstruction of corresponding electrical brain sources. An MEG and simultaneous EEG studies were recorded with a 275-channel whole-head system. Single-equivalent current dipoles were estimated from the MEG data, and dipole locations and orientations were superimposed on patients' MR images. Results The MS imaging studies revealed focal dipole clusters in 12 (75%) of the 16 patients, of which a single dipole cluster was identified in 7 patients (44%). Patient age, seizure type, duration of disease, video-EEG telemetry, and MR imaging results were analyzed to determine factors predictive of having clusters revealed on MS imaging. Of these factors, only focal MR imaging anatomical abnormalities were associated with dipole clusters (chi-square test, p = 0.03). Selective resections (including the dipole cluster) in 7 (87%) of 8 patients resulted in seizure-free or rare seizure outcomes (Engel Classes I and II). Conclusions Magnetic source imaging may provide noninvasive anatomical and neurophysiological confirmation of localization in patients in whom there is a suspicion of SBS (based on clinical or MR imaging data), especially in those with an anatomical lesion. Identification of a focal seizure origin has significant implications for both resective and nonresective treatment of intractable epilepsy.

scholarly journals Detection and Magnetic Source Imaging of Fast Oscillations (40–160 Hz) Recorded with Magnetoencephalography in Focal Epilepsy Patients

2016 ◽  
Vol 29 (2) ◽  
pp. 218-231 ◽  
Author(s):  
Nicolás von Ellenrieder ◽  
Giovanni Pellegrino ◽  
Tanguy Hedrich ◽  
Jean Gotman ◽  
Jean-Marc Lina ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Magnetic Source ◽  
Fast Oscillations

Magnetic source imaging (MSI) in children with neocortical epilepsy: Surgical outcome association with 3D post-resection analysis

2013 ◽  
Vol 106 (1-2) ◽  
pp. 164-172 ◽  
Author(s):  
Hyunmi Kim ◽  
Pongkiat Kankirawatana ◽  
Jeff Killen ◽  
Allan Harrison ◽  
Ahyuda Oh ◽  
...  
Keyword(s):  
Surgical Outcome ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Magnetic Source ◽  
Neocortical Epilepsy

Magnetic Source Imaging in the Evaluation of Chronic Alcohol Abuse

Biomag 96 ◽  
2000 ◽  
pp. 1011-1013
Author(s):  
D. Hill ◽  
V. A. Waldorf ◽  
J. D. Lewine ◽  
S. L. Provencal ◽  
T. Moyers ◽  
...  
Keyword(s):  
Alcohol Abuse ◽  
Chronic Alcohol ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Chronic Alcohol Abuse ◽  
Magnetic Source

Presurgical localization of functional cortex using magnetic source imaging

1995 ◽  
Vol 82 (6) ◽  
pp. 988-994 ◽  
Author(s):  
Christopher C. Gallen ◽  
Barry J. Schwartz ◽  
Richard D. Bucholz ◽  
Ghaus Malik ◽  
Gregory L. Barkley ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Preoperative Planning ◽  
Source Imaging ◽  
Magnetic Source Imaging ◽  
Minimum Risk ◽  
Content Type ◽  
Magnetic Source ◽  
Two Measures ◽  
Eloquent Cortex ◽  
Mass Lesions

✓ The boundaries of somatosensory cortex were localized noninvasively by means of a large-array biomagnetometer in six patients with mass lesions in or near eloquent cortex. The results were used by neurosurgeons and neurologists in preoperative planning and for reference in the operating room. The magnetic source imaging (MSI) localizations from somatosensory evoked potentials were used to predict the pattern of phase reversals measurable intraoperatively on the cortical surface, providing a quantitative comparison between the two measures. The magnetic localizations were found to be predictive in all six cases, with the two sets of localizations falling within an 8-mm distance on average. Somatosensory localizations using MSI offer accuracy in localizing somatosensory cortex stereotactically and in depicting its relationship to lesions. Such data are valuable preoperatively in assessing the risks associated with a proposed surgical procedure and for optimizing subsequent minimum-risk surgical strategy.

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