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Hao G, Yan H, Wang X, Gao R, Xue Y, Zhang X, Ni D, Shu W, Qiao L, He L, Yu T. The role of magnetoencephalography in preoperative localization and postoperative outcome prediction in patients with posterior cortical epilepsy. CNS Neurosci Ther 2024; 30:e14602. [PMID: 38332652 PMCID: PMC10853654 DOI: 10.1111/cns.14602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/16/2023] [Accepted: 01/01/2024] [Indexed: 02/10/2024] Open
Abstract
OBJECTIVE We aimed to explore the value of magnetoencephalography in the presurgical evaluation of patients with posterior cortex epilepsy. METHODS A total of 39 patients with posterior cortex epilepsy (PCE) and intact magnetoencephalography (MEG) images were reviewed from August 2019 to July 2022. MEG dipole clusters were classified into single clusters, multiple clusters, and scatter dipoles based on tightness criteria. The association of the surgical outcome with MEG dipole classifications was evaluated using Fisher's exact tests. RESULTS Among the 39 cases, there were 24 cases of single clusters (61.5%), nine cases of multiple clusters (23.1%), and six cases of scattered dipoles (15.4%). Patients with single dipole clusters were more likely to become seizure-free. Among single dipole cluster cases (n = 24), complete MEG dipole resection yielded a more favorable surgical outcome than incomplete resection (83.3% vs. 16.7%, p = 0.007). Patients with concordant MRI and MEG findings achieved a significantly more favorable surgical outcome than discordant patients (66.7% vs. 33.3%, p = 0.044), especially in single dipole cluster patients (87.5% vs. 25.0%, p = 0.005). SIGNIFICANCE MEG can provide additional valuable information regarding surgical candidate selection, epileptogenic zone localization, electrode implantation schedule, and final surgical planning in patients with posterior cortex epilepsy.
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Affiliation(s)
- Guiliang Hao
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Hao Yan
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Xueyuan Wang
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Runshi Gao
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Yansong Xue
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Xiating Zhang
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Duanyu Ni
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Wei Shu
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Liang Qiao
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Liu He
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Tao Yu
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
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2
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Seedat ZA, Rier L, Gascoyne LE, Cook H, Woolrich MW, Quinn AJ, Roberts TPL, Furlong PL, Armstrong C, St. Pier K, Mullinger KJ, Marsh ED, Brookes MJ, Gaetz W. Mapping Interictal activity in epilepsy using a hidden Markov model: A magnetoencephalography study. Hum Brain Mapp 2022; 44:66-81. [PMID: 36259549 PMCID: PMC9783449 DOI: 10.1002/hbm.26118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 02/05/2023] Open
Abstract
Epilepsy is a highly heterogeneous neurological disorder with variable etiology, manifestation, and response to treatment. It is imperative that new models of epileptiform brain activity account for this variability, to identify individual needs and allow clinicians to curate personalized care. Here, we use a hidden Markov model (HMM) to create a unique statistical model of interictal brain activity for 10 pediatric patients. We use magnetoencephalography (MEG) data acquired as part of standard clinical care for patients at the Children's Hospital of Philadelphia. These data are routinely analyzed using excess kurtosis mapping (EKM); however, as cases become more complex (extreme multifocal and/or polymorphic activity), they become harder to interpret with EKM. We assessed the performance of the HMM against EKM for three patient groups, with increasingly complicated presentation. The difference in localization of epileptogenic foci for the two methods was 7 ± 2 mm (mean ± SD over all 10 patients); and 94% ± 13% of EKM temporal markers were matched by an HMM state visit. The HMM localizes epileptogenic areas (in agreement with EKM) and provides additional information about the relationship between those areas. A key advantage over current methods is that the HMM is a data-driven model, so the output is tuned to each individual. Finally, the model output is intuitive, allowing a user (clinician) to review the result and manually select the HMM epileptiform state, offering multiple advantages over previous methods and allowing for broader implementation of MEG epileptiform analysis in surgical decision-making for patients with intractable epilepsy.
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Affiliation(s)
- Zelekha A. Seedat
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK,Young EpilepsySt Pier's LaneLingfieldRH7 6PWUK
| | - Lukas Rier
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK
| | - Lauren E. Gascoyne
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK
| | - Harry Cook
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK
| | - Mark W. Woolrich
- Oxford Centre for Human Brain ActivityUniversity Department of Psychiatry, Warneford HospitalOxfordUK
| | - Andrew J. Quinn
- Oxford Centre for Human Brain ActivityUniversity Department of Psychiatry, Warneford HospitalOxfordUK
| | - Timothy P. L. Roberts
- Department of RadiologyChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | | | - Caren Armstrong
- Department of RadiologyChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA,Pediatric Epilepsy Program, Division of Child NeurologyCHOPPhiladelphiaPennsylvaniaUSA
| | | | - Karen J. Mullinger
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK,Centre for Human Brain Health, School of PsychologyUniversity of BirminghamBirminghamUK
| | - Eric D. Marsh
- Department of RadiologyChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA,Pediatric Epilepsy Program, Division of Child NeurologyCHOPPhiladelphiaPennsylvaniaUSA,Departments of Neurology and PaediatricsUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvaniaUSA
| | - Matthew J. Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and AstronomyUniversity of NottinghamNottinghamUK
| | - William Gaetz
- Department of RadiologyChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
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3
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Zhang C, Liu W, Zhang J, Zhang X, Huang P, Sun B, Zhan S, Cao C. Utility of magnetoencephalography combined with stereo-electroencephalography in resective epilepsy surgery: a 2-year follow-up. Seizure 2022; 97:94-101. [DOI: 10.1016/j.seizure.2022.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/25/2022] Open
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4
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Laohathai C, Ebersole JS, Mosher JC, Bagić AI, Sumida A, Von Allmen G, Funke ME. Practical Fundamentals of Clinical MEG Interpretation in Epilepsy. Front Neurol 2021; 12:722986. [PMID: 34721261 PMCID: PMC8551575 DOI: 10.3389/fneur.2021.722986] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/06/2021] [Indexed: 11/29/2022] Open
Abstract
Magnetoencephalography (MEG) is a neurophysiologic test that offers a functional localization of epileptic sources in patients considered for epilepsy surgery. The understanding of clinical MEG concepts, and the interpretation of these clinical studies, are very involving processes that demand both clinical and procedural expertise. One of the major obstacles in acquiring necessary proficiency is the scarcity of fundamental clinical literature. To fill this knowledge gap, this review aims to explain the basic practical concepts of clinical MEG relevant to epilepsy with an emphasis on single equivalent dipole (sECD), which is one the most clinically validated and ubiquitously used source localization method, and illustrate and explain the regional topology and source dynamics relevant for clinical interpretation of MEG-EEG.
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Affiliation(s)
- Christopher Laohathai
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
- Department of Neurology, Saint Louis University, Saint Louis, MO, United States
| | - John S. Ebersole
- Northeast Regional Epilepsy Group, Atlantic Health Neuroscience Institute, Summit, NJ, United States
| | - John C. Mosher
- Department of Neurology, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Anto I. Bagić
- University of Pittsburgh Comprehensive Epilepsy Center (UPCEC), Department of Neurology, University of Pittsburgh Medical Center, Pittsburg, PA, United States
| | - Ai Sumida
- Department of Neurology, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Gretchen Von Allmen
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
| | - Michael E. Funke
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School at UTHealth, Houston, TX, United States
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5
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van Mierlo P, Vorderwülbecke BJ, Staljanssens W, Seeck M, Vulliémoz S. Ictal EEG source localization in focal epilepsy: Review and future perspectives. Clin Neurophysiol 2020; 131:2600-2616. [PMID: 32927216 DOI: 10.1016/j.clinph.2020.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/12/2020] [Accepted: 08/04/2020] [Indexed: 11/25/2022]
Abstract
Electroencephalographic (EEG) source imaging localizes the generators of neural activity in the brain. During presurgical epilepsy evaluation, EEG source imaging of interictal epileptiform discharges is an established tool to estimate the irritative zone. However, the origin of interictal activity can be partly or fully discordant with the origin of seizures. Therefore, source imaging based on ictal EEG data to determine the seizure onset zone can provide precious clinical information. In this descriptive review, we address the importance of localizing the seizure onset zone based on noninvasive EEG recordings as a complementary analysis that might reduce the burden of the presurgical evaluation. We identify three major challenges (low signal-to-noise ratio of the ictal EEG data, spread of ictal activity in the brain, and validation of the developed methods) and discuss practical solutions. We provide an extensive overview of the existing clinical studies to illustrate the potential clinical utility of EEG-based localization of the seizure onset zone. Finally, we conclude with future perspectives and the needs for translating ictal EEG source imaging into clinical practice.
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Affiliation(s)
- Pieter van Mierlo
- Medical Image and Signal Processing Group, Department of Electronics and Information Systems, Ghent University, Corneel Heymanslaan 10, 9000 Ghent, Belgium.
| | - Bernd J Vorderwülbecke
- EEG and Epilepsy Unit, University Hospitals and Faculty of Medicine Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland; Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Willeke Staljanssens
- Medical Image and Signal Processing Group, Department of Electronics and Information Systems, Ghent University, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Margitta Seeck
- EEG and Epilepsy Unit, University Hospitals and Faculty of Medicine Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
| | - Serge Vulliémoz
- EEG and Epilepsy Unit, University Hospitals and Faculty of Medicine Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
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6
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Pellegrino G, Xu M, Alkuwaiti A, Porras-Bettancourt M, Abbas G, Lina JM, Grova C, Kobayashi E. Effects of Independent Component Analysis on Magnetoencephalography Source Localization in Pre-surgical Frontal Lobe Epilepsy Patients. Front Neurol 2020; 11:479. [PMID: 32582009 PMCID: PMC7280485 DOI: 10.3389/fneur.2020.00479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/01/2020] [Indexed: 01/18/2023] Open
Abstract
Objective: Magnetoencephalography source imaging (MSI) of interictal epileptiform discharges (IED) is a useful presurgical tool in the evaluation of drug-resistant frontal lobe epilepsy (FLE) patients. Yet, failures in MSI can arise related to artifacts and to interference of background activity. Independent component analysis (ICA) is a popular denoising procedure but its clinical application remains challenging, as the selection of multiple independent components (IC) is controversial, operator dependent, and time consuming. We evaluated whether selecting only one IC of interest based on its similarity with the average IED field improves MSI in FLE. Methods: MSI was performed with the equivalent current dipole (ECD) technique and two distributed magnetic source imaging (dMSI) approaches: minimum norm estimate (MNE) and coherent Maximum Entropy on the Mean (cMEM). MSI accuracy was evaluated under three conditions: (1) ICA of continuous data (Cont_ICA), (2) ICA at the time of IED (IED_ICA), and (3) without ICA (No_ICA). Localization performance was quantitatively measured as actual distance of the source maximum in relation to the focus (Dmin), and spatial dispersion (SD) for dMSI. Results: After ICA, ECD Dmin did not change significantly (p > 0.200). For both dMSI techniques, ICA application worsened the source localization accuracy. We observed a worsening of both MNE Dmin (p < 0.05, consistently) and MNE SD (p < 0.001, consistently) for both ICA approaches. A similar behaviour was observed for cMEM, for which, however, Cont_ICA seemed less detrimental. Conclusion: We demonstrated that a simplified ICA approach selecting one IC of interest in combination with distributed magnetic source imaging can be detrimental. More complex approaches may provide better results but would be rather difficult to apply in real-world clinical setting. In a broader perspective, caution should be taken in applying ICA for source localization of interictal activity. To ensure optimal and useful results, effort should focus on acquiring good quality data, minimizing artifacts, and determining optimal candidacy for MEG, rather than counting on data cleaning techniques.
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Affiliation(s)
- Giovanni Pellegrino
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Min Xu
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Department of Geriatrics, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Abdulla Alkuwaiti
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Manuel Porras-Bettancourt
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Ghada Abbas
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Jean-Marc Lina
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, McGill University, Montreal, QC, Canada.,Département de Génie Électrique, École de Technologie Supérieure, Montreal, QC, Canada.,Centre de Recherches Mathematiques, Univeristé de Montréal, Montreal, QC, Canada
| | - Christophe Grova
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, McGill University, Montreal, QC, Canada.,Département de Génie Électrique, École de Technologie Supérieure, Montreal, QC, Canada.,Physics Department and PERFORM Centre, Concordia University, Montreal, QC, Canada
| | - Eliane Kobayashi
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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7
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Pellegrino G, Hedrich T, Porras-Bettancourt M, Lina JM, Aydin Ü, Hall J, Grova C, Kobayashi E. Accuracy and spatial properties of distributed magnetic source imaging techniques in the investigation of focal epilepsy patients. Hum Brain Mapp 2020; 41:3019-3033. [PMID: 32386115 PMCID: PMC7336148 DOI: 10.1002/hbm.24994] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/18/2020] [Accepted: 03/11/2020] [Indexed: 02/03/2023] Open
Abstract
Source localization of interictal epileptiform discharges (IEDs) is clinically useful in the presurgical workup of epilepsy patients. We aimed to compare the performance of four different distributed magnetic source imaging (dMSI) approaches: Minimum norm estimate (MNE), dynamic statistical parametric mapping (dSPM), standardized low-resolution electromagnetic tomography (sLORETA), and coherent maximum entropy on the mean (cMEM). We also evaluated whether a simple average of maps obtained from multiple inverse solutions (Ave) can improve localization accuracy. We analyzed dMSI of 206 IEDs derived from magnetoencephalography recordings in 28 focal epilepsy patients who had a well-defined focus determined through intracranial EEG (iEEG), epileptogenic MRI lesions or surgical resection. dMSI accuracy and spatial properties were quantitatively estimated as: (a) distance from the epilepsy focus, (b) reproducibility, (c) spatial dispersion (SD), (d) map extension, and (e) effect of thresholding on map properties. Clinical performance was excellent for all methods (median distance from the focus MNE = 2.4 mm; sLORETA = 3.5 mm; cMEM = 3.5 mm; dSPM = 6.8 mm, Ave = 0 mm). Ave showed the lowest distance between the map maximum and epilepsy focus (Dmin lower than cMEM, MNE, and dSPM, p = .021, p = .008, p < .001, respectively). cMEM showed the best spatial features, with lowest SD outside the focus (SD lower than all other methods, p < .001 consistently) and high contrast between the generator and surrounding regions. The average map Ave provided the best localization accuracy, whereas cMEM exhibited the lowest amount of spurious distant activity. dMSI techniques have the potential to significantly improve identification of iEEG targets and to guide surgical planning, especially when multiple methods are combined.
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Affiliation(s)
- Giovanni Pellegrino
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.,IRCCS Fondazione San Camillo Hospital, Venice, Italy.,Department of Multimodal Functional Imaging Lab, Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Tanguy Hedrich
- Department of Multimodal Functional Imaging Lab, Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Manuel Porras-Bettancourt
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jean-Marc Lina
- Departement de Genie Electrique, Ecole de Technologie Superieure, Montreal, Quebec, Canada.,Centre de Recherches Mathematiques, Montréal, Quebec, Canada
| | - Ümit Aydin
- Physics Department and PERFORM Centre, Concordia University, Montreal, Quebec, Canada
| | - Jeffery Hall
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Christophe Grova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.,Department of Multimodal Functional Imaging Lab, Biomedical Engineering, McGill University, Montreal, Quebec, Canada.,Centre de Recherches Mathematiques, Montréal, Quebec, Canada.,Physics Department and PERFORM Centre, Concordia University, Montreal, Quebec, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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8
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Gofshteyn JS, Le T, Kessler S, Kamens R, Carr C, Gaetz W, Bloy L, Roberts TPL, Schwartz ES, Marsh ED. Synthetic aperture magnetometry and excess kurtosis mapping of Magnetoencephalography (MEG) is predictive of epilepsy surgical outcome in a large pediatric cohort. Epilepsy Res 2019; 155:106151. [PMID: 31247475 PMCID: PMC6699633 DOI: 10.1016/j.eplepsyres.2019.106151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/23/2019] [Accepted: 06/09/2019] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Resective surgery is the most effective treatment option for patients with refractory epilepsy; however identification of patients who will benefit from epilepsy surgery remains challenging. Synthetic aperture magnetometry and excess kurtosis mapping (SAM(g2)) of magnetoencephalography (MEG) is a non-invasive tool that warrants further examination in the pediatric epilepsy population. Here, we examined the utility of MEG with SAM(g2) to determine if MEG epileptiform foci correlates with surgical outcome and to develop a predictive model incorporating MEG information to best assess likelihood of seizure improvement/freedom from resective surgery. METHODS 564 subjects who had MEG at the Children's Hospital of Philadelphia between 2010-2015 were screened. Clinical epilepsy history and prior electrographic records were extracted and reviewed and correlated with MEG findings. MEG assessments were made by both a neurologist and neuroradiologist. Predictive models were developed to assess the utility of MEG in determining Engel class at one year and five years after resective epilepsy surgery. RESULTS The number of MEG spike foci was highly associated with Engel class outcome at both one year and five years; however, using MEG data in isolation was not significantly predictive of 5 year surgical outcome. When combined with clinical factors; scalp EEG (single ictal onset zone), MRI (lesional or not), age and sex in a logistic regression model MEG foci was significant for Engel class outcome at both 1 year (p = 0.03) and 5 years (0.02). The percent correctly classified for Engel class at one year was 78.43% and the positive predictive value was 71.43. SIGNIFICANCE MEG using SAM(g2) analysis in an important non-invasive tool in the identification of those patients who will benefit most from surgery. Integrating MEG data analysis into pre-surgical evaluation can help to predict epilepsy outcome after resective surgery in the pediatric population if utilized with skilled interpretation.
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Affiliation(s)
- J S Gofshteyn
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, NY, United States; New-York Presbyterian Hospital, New York, NY, United States
| | - T Le
- Division of Pediatric Neurology, The Children's Hospital of Philadelphia, United States
| | - S Kessler
- Division of Pediatric Neurology, The Children's Hospital of Philadelphia, United States; Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, United States
| | - R Kamens
- Division of Pediatric Neurology, The Children's Hospital of Philadelphia, United States
| | - C Carr
- Division of Pediatric Neurology, The Children's Hospital of Philadelphia, United States
| | - W Gaetz
- Division of Neuroradiology, Department of Radiology, The Children's Hospital of Philadelphia, United States; Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, United States
| | - L Bloy
- Division of Neuroradiology, Department of Radiology, The Children's Hospital of Philadelphia, United States; Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, United States
| | - T P L Roberts
- Division of Neuroradiology, Department of Radiology, The Children's Hospital of Philadelphia, United States; Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, United States
| | - E S Schwartz
- Division of Neuroradiology, Department of Radiology, The Children's Hospital of Philadelphia, United States; Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, United States
| | - E D Marsh
- Division of Pediatric Neurology, The Children's Hospital of Philadelphia, United States; Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, United States.
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9
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Mouthaan BE, Rados M, Boon P, Carrette E, Diehl B, Jung J, Kimiskidis V, Kobulashvili T, Kuchukhidze G, Larsson PG, Leitinger M, Ryvlin P, Rugg-Gunn F, Seeck M, Vulliémoz S, Huiskamp G, Leijten FSS, Van Eijsden P, Trinka E, Braun KPJ. Diagnostic accuracy of interictal source imaging in presurgical epilepsy evaluation: A systematic review from the E-PILEPSY consortium. Clin Neurophysiol 2019; 130:845-855. [PMID: 30824202 DOI: 10.1016/j.clinph.2018.12.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 11/16/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Interictal high resolution (HR-) electric source imaging (ESI) and magnetic source imaging (MSI) are non-invasive tools to aid epileptogenic zone localization in epilepsy surgery candidates. We carried out a systematic review on the diagnostic accuracy and quality of evidence of these modalities. METHODS Embase, Pubmed and the Cochrane database were searched on 13 February 2017. Diagnostic accuracy studies taking post-surgical seizure outcome as reference standard were selected. Quality appraisal was based on the QUADAS-2 framework. RESULTS Eleven studies were included: eight MSI (n = 267), three HR-ESI (n = 127) studies. None was free from bias. This mostly involved: selection of operated patients only, interference of source imaging with surgical decision, and exclusion of indeterminate results. Summary sensitivity and specificity estimates were 82% (95% CI: 75-88%) and 53% (95% CI: 37-68%) for overall source imaging, with no statistical difference between MSI and HR-ESI. Specificity is higher when partially concordant results were included as non-concordant (p < 0.05). Inclusion of indeterminate test results as non-concordant lowered sensitivity (p < 0.05). CONCLUSIONS Source imaging has a relatively high sensitivity but low specificity for identification of the epileptogenic zone. SIGNIFICANCE We need higher quality studies allowing unbiased test evaluation to determine the added value and diagnostic accuracy of source imaging in the presurgical workup of refractory focal epilepsy.
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Affiliation(s)
- Brian E Mouthaan
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Matea Rados
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Paul Boon
- Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, Belgium
| | - Evelien Carrette
- Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, Belgium
| | - Beate Diehl
- National Hospital for Neurology and Neurosurgery, University College London Hospitals, London, United Kingdom; Department of Clinical and Experimental Epilepsy, University College, London, UK
| | - Julien Jung
- Department of Functional Neurology and Epileptology, Institute of Epilepsies (IDEE), Hospices Civils de Lyon, Lyon, France
| | - Vasilios Kimiskidis
- Laboratory of Clinical Neurophysiology, Medical School, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Teia Kobulashvili
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Giorgi Kuchukhidze
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Pål G Larsson
- Department of Neurosurgery, Clinic of Surgery and Neuroscience, Oslo University Hospital, Norway
| | - Markus Leitinger
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria
| | - Philippe Ryvlin
- Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland
| | - Fergus Rugg-Gunn
- National Hospital for Neurology and Neurosurgery, University College London Hospitals, London, United Kingdom; Department of Clinical and Experimental Epilepsy, University College, London, UK
| | - Margitta Seeck
- EEG and Epilepsy Unit, Department of Clinical Neurosciences, University Hospital of Geneva, Switzerland
| | - Serge Vulliémoz
- EEG and Epilepsy Unit, Department of Clinical Neurosciences, University Hospital of Geneva, Switzerland
| | - Geertjan Huiskamp
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Frans S S Leijten
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Pieter Van Eijsden
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands
| | - Eugen Trinka
- Department of Neurology, Christian-Doppler University Hospital, Paracelsus Medical University, and Centre for Cognitive Neuroscience, Salzburg, Austria; Institute of Public Health, Medical Decision Making and HTA, UMIT, Private University for Health Sciences, Medical Informatics and Technology, Hall in Tyrol, Austria
| | - Kees P J Braun
- Department of (Child) Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands.
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Hall MBH, Nissen IA, van Straaten ECW, Furlong PL, Witton C, Foley E, Seri S, Hillebrand A. An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients. Clin Neurophysiol 2018; 129:1221-1229. [PMID: 29660580 PMCID: PMC5953276 DOI: 10.1016/j.clinph.2017.12.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 11/12/2017] [Accepted: 12/30/2017] [Indexed: 11/23/2022]
Abstract
Objective localizations of interictal spikes using a kurtosis beamformer. Kurtosis Beamforming can provide confidence to scattered dipoles. Kurtosis beamforming can assist in localizing the epileptogenic zone.
Objective Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients. Methods We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas. Results The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%). Conclusions Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered. Significance Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.
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Affiliation(s)
- Michael B H Hall
- Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
| | - Ida A Nissen
- Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands
| | - Elisabeth C W van Straaten
- Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands
| | - Paul L Furlong
- Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Caroline Witton
- Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Elaine Foley
- Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Stefano Seri
- Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK; Department of Clinical Neurophysiology and Paediatric Epilepsy Surgery Programme, The Birmingham Children's Hospital NHS Foundation Trust, Birmingham, UK
| | - Arjan Hillebrand
- Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands
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Feyissa AM, Britton JW, Van Gompel J, Lagerlund TL, So E, Wong-Kisiel LC, Cascino GC, Brinkman BH, Nelson CL, Watson R, Worrell GA. High density scalp EEG in frontal lobe epilepsy. Epilepsy Res 2017; 129:157-161. [PMID: 28073096 DOI: 10.1016/j.eplepsyres.2016.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/27/2016] [Accepted: 12/31/2016] [Indexed: 10/20/2022]
Abstract
PURPOSE Localization of seizures in frontal lobe epilepsy using the 10-20 system scalp EEG is often challenging because neocortical seizure can spread rapidly, significant muscle artifact, and the suboptimal spatial resolution for seizure generators involving mesial frontal lobe cortex. Our aim in this study was to determine the value of visual interpretation of 76 channel high density EEG (hdEEG) monitoring (10-10 system) in patients with suspected frontal lobe epilepsy, and to evaluate concordance with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional EEG, and intracranial EEG (iEEG). METHODS We performed a retrospective cohort study of 14 consecutive patients who underwent hdEEG monitoring for suspected frontal lobe seizures. The gold standard for localization was considered to be iEEG. Concordance of hdEEG findings with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional 10-20 EEG, and iEEG as well as correlation of hdEEG localization with surgical outcome were examined. RESULTS hdEEG localization was concordant with iEEG in 12/14 and was superior to conventional EEG 3/14 (p<0.01) and SISCOM 3/12 (p<0.01). hdEEG correctly lateralized seizure onset in 14/14 cases, compared to 9/14 (p=0.04) cases with conventional EEG. Seven patients underwent surgical resection, of whom five were seizure free. CONCLUSIONS hdEEG monitoring should be considered in patients with suspected frontal epilepsy requiring localization of epileptogenic brain. hdEEG may assist in developing a hypothesis for iEEG monitoring and could potentially augment EEG source localization.
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Affiliation(s)
- Anteneh M Feyissa
- Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, United States.
| | - Jeffrey W Britton
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Jamie Van Gompel
- Departments of Neurological Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Terrance L Lagerlund
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Elson So
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Lilly C Wong-Kisiel
- Division of Child and Adolescent Neurology, Mayo Clinic Children's Center, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Gregory C Cascino
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Benjamin H Brinkman
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Cindy L Nelson
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Robert Watson
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
| | - Gregory A Worrell
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States.
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12
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Magnetoencephalography-guided surgery in frontal lobe epilepsy using neuronavigation and intraoperative MR imaging. Epilepsy Res 2016; 126:26-36. [DOI: 10.1016/j.eplepsyres.2016.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/01/2016] [Accepted: 06/24/2016] [Indexed: 11/17/2022]
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Kim D, Joo EY, Seo DW, Kim MY, Lee YH, Kwon HC, Kim JM, Hong SB. Accuracy of MEG in localizing irritative zone and seizure onset zone: Quantitative comparison between MEG and intracranial EEG. Epilepsy Res 2016; 127:291-301. [PMID: 27693985 DOI: 10.1016/j.eplepsyres.2016.08.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/25/2016] [Accepted: 08/14/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND We conducted the study to examine accuracy of the magnetoencephalography (MEG) spike source localization in presurgical evaluation of patients with medically refractory focal epilepsy. METHODS Ten consecutive patients with refractory focal epilepsy who were candidates for two-stage surgery with long-term intracranial electroencephalography (ICEEG) monitoring were enrolled. Interictal MEG recordings with simultaneous scalp EEG were obtained within 7days before the ICEEG electrode implantation. The location of each MEG spike source was quantitatively compared with ICEEG spike foci (focal area of interictal spikes) and ICEEG ictal foci (earliest cortical origin of seizures). Gyral-width concordance and sublobar concordance were also determined for all MEG spike sources. Gyral-width concordance was defined by distance of 15mm or less between MEG spike sources and ICEEG spike foci or ICEEG ictal foci. RESULTS Visual analyses of the MEG traces of all 10 patients revealed 292 spikes (29.2±24.0 per patient). Spike yield of the MEG was similar to the simultaneously recorded scalp EEG. MEG spike sources were closely located with ICEEG spike foci (distance: 9.3±10.8mm). Clustered MEG spike sources were even closer to ICEEG spike foci (distance: 7.3±6.4mm). MEG spike sources, even clustered ones, were less concordant with ICEEG ictal foci and had significant longer distance from ICEEG ictal foci (distance: 21.5±15.6mm for all sources, 19.7±13.7mm for clustered sources). Gyral-width concordance rate and sublobar concordance rate were also higher with ICEEG interictal spike foci than with ICEEG ictal foci. On the other hand, 53.4% of interictal spike foci from ICEEG were not detected by interictal MEG recordings. CONCLUSIONS MEG spike sources, especially clustered ones, from interictal recording could localize the irritative zone of ICEEG with a high accuracy. However, MEG spike sources have relatively poor correlation with seizure onset zone and lower sensitivity in identifying all irritative zones of ICEEG. This limitation should be considered in the interpretation of MEG results.
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Affiliation(s)
- Daeyoung Kim
- Department of Neurology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Eun Yeon Joo
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dae-Won Seo
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Min-Young Kim
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Yong-Ho Lee
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Hyuk Chan Kwon
- Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Jae-Moon Kim
- Department of Neurology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea.
| | - Seung Bong Hong
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Samsung Biomedical Research Institute, Seoul, Republic of Korea.
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Zhu H, Zhu J, Bao FS, Liu H, Zhu X, Wu T, Yang L, Zou Y, Zhang R, Zheng G. Statistical parametric mapping for analyzing interictal magnetoencephalography in patients with left frontal lobe epilepsy. Seizure 2015; 34:38-43. [PMID: 26707266 DOI: 10.1016/j.seizure.2015.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 11/11/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022] Open
Abstract
PURPOSE Frontal lobe epilepsy is a common epileptic disorder and is characterized by recurring seizures that arise in the frontal lobes. The purpose of this study is to identify the epileptogenic regions and other abnormal regions in patients with left frontal lobe epilepsy (LFLE) based on the magnetoencephalogram (MEG), and to understand the effects of clinical variables on brain activities in patients with LFLE. METHOD Fifteen patients with LFLE (23.20 ± 8.68 years, 6 female and 9 male) and 16 healthy controls (23.13 ± 7.66 years, 6 female and 10 male) were included in resting-stage MEG examinations. Epileptogenic regions of LFLE patients were confirmed by surgery. Regional brain activations were quantified using statistical parametric mapping (SPM). The correlation between the activations of the abnormal brain regions and the clinical seizure parameters were computed for LFLE patients. RESULTS Brain activations of LFLE patients were significantly elevated in left superior/middle/inferior frontal gyri, postcentral gyrus, inferior temporal gyrus, insula, parahippocampal gyrus and amygdala, including the epileptogenic regions. Remarkable decreased activations were found mainly in the left parietal gyrus and precuneus. There is a positive correlation between the duration of the epilepsy (in month) and activations of the abnormal regions, while no relation was found between age of seizure onset (year), seizure frequency and the regions of the abnormal activity of the epileptic patients. CONCLUSION Our findings suggest that the aberrant brain activities of LFLE patients were not restricted to the epileptogenic zones. Long duration of epilepsy might induce further functional damage in patients with LFLE.
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Affiliation(s)
- Haitao Zhu
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Jinlong Zhu
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Forrest Sheng Bao
- Department of Electrical and Computer Engineering, University of Akron, Akron, OH, USA
| | - Hongyi Liu
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xuchuang Zhu
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Ting Wu
- MEG Center, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Lu Yang
- MEG Center, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Yuanjie Zou
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Rui Zhang
- Department of Neurosurgery, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing 210029, Jiangsu, China.
| | - Gang Zheng
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu, China; College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, Jiangsu, China.
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Idris Z, Kandasamy R, Reza F, Abdullah JM. Neural oscillation, network, eloquent cortex and epileptogenic zone revealed by magnetoencephalography and awake craniotomy. Asian J Neurosurg 2015; 9:144-52. [PMID: 25685205 PMCID: PMC4323898 DOI: 10.4103/1793-5482.142734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Magnetoencephalography (MEG) is a method of functional neuroimaging. The concomitant use of MEG and electrocorticography has been found to be useful in elucidating neural oscillation and network, and to localize epileptogenic zone and functional cortex. We describe our early experience using MEG in neurosurgical patients, emphasizing on its impact on patient management as well as the enrichment of our knowledge in neurosciences. MATERIALS AND METHODS A total of 10 subjects were included; five patients had intraaxial tumors, one with an extraaxial tumor and brain compression, two with arteriovenous malformations, one with cerebral peduncle hemorrhage and one with sensorimotor cortical dysplasia. All patients underwent evoked and spontaneous MEG recordings. MEG data was processed at band-pass filtering frequency of between 0.1 and 300 Hz with a sampling rate of 1 kHz. MEG source localization was performed using either overdetermined equivalent current dipoles or underdetermined inversed solution. Neuromag collection of events software was used to study brain network and epileptogenic zone. The studied data were analyzed for neural oscillation in three patients; brain network and clinical manifestation in five patients; and for the location of epileptogenic zone and eloquent cortex in two patients. RESULTS We elucidated neural oscillation in three patients. One demonstrated oscillatory phenomenon on stimulation of the motor-cortex during awake surgery, and two had improvement in neural oscillatory parameters after surgery. Brain networks corresponding to clinico-anatomical relationships were depicted in five patients, and two networks were illustrated here. Finally, we demonstrated epilepsy cases in which MEG data was found to be useful in localizing the epileptogenic zones and functional cortices. CONCLUSION The application of MEG while enhancing our knowledge in neurosciences also has a useful role in epilepsy and awake surgery.
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Affiliation(s)
- Zamzuri Idris
- Center for Neuroscience Service and Research, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia ; Department of Neurosciences, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia
| | - Regunath Kandasamy
- Department of Neurosciences, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia
| | - Faruque Reza
- Department of Neurosciences, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia
| | - Jafri M Abdullah
- Center for Neuroscience Service and Research, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia ; Department of Neurosciences, School of Medical Sciences, Center for Neuroscience Service and Research, Universiti Sains Malaysia, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia
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Mu J, Rampp S, Carrette E, Roessler K, Sommer B, Schmitt FC, De Tiège X, Hamer H, Boon P, Pauli E, Bluemcke I, Zhou D, Buchfelder M, Stefan H. Clinical relevance of source location in frontal lobe epilepsy and prediction of postoperative long-term outcome. Seizure 2014; 23:553-9. [DOI: 10.1016/j.seizure.2014.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 03/04/2014] [Accepted: 04/10/2014] [Indexed: 11/26/2022] Open
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Dipole source localization of mouse electroencephalogram using the Fieldtrip toolbox. PLoS One 2013; 8:e79442. [PMID: 24244506 PMCID: PMC3828402 DOI: 10.1371/journal.pone.0079442] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 09/24/2013] [Indexed: 11/20/2022] Open
Abstract
The mouse model is an important research tool in neurosciences to examine brain function and diseases with genetic perturbation in different brain regions. However, the limited techniques to map activated brain regions under specific experimental manipulations has been a drawback of the mouse model compared to human functional brain mapping. Here, we present a functional brain mapping method for fast and robust in vivo brain mapping of the mouse brain. The method is based on the acquisition of high density electroencephalography (EEG) with a microarray and EEG source estimation to localize the electrophysiological origins. We adapted the Fieldtrip toolbox for the source estimation, taking advantage of its software openness and flexibility in modeling the EEG volume conduction. Three source estimation techniques were compared: Distribution source modeling with minimum-norm estimation (MNE), scanning with multiple signal classification (MUSIC), and single-dipole fitting. Known sources to evaluate the performance of the localization methods were provided using optogenetic tools. The accuracy was quantified based on the receiver operating characteristic (ROC) analysis. The mean detection accuracy was high, with a false positive rate less than 1.3% and 7% at the sensitivity of 90% plotted with the MNE and MUSIC algorithms, respectively. The mean center-to-center distance was less than 1.2 mm in single dipole fitting algorithm. Mouse microarray EEG source localization using microarray allows a reliable method for functional brain mapping in awake mouse opening an access to cross-species study with human brain.
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Jin SH, Jeong W, Chung CK. Information source in multiple MEG spike clusters can be identified by effective connectivity in focal cortical dysplasia. Epilepsy Res 2013; 105:118-24. [DOI: 10.1016/j.eplepsyres.2013.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/07/2012] [Accepted: 01/22/2013] [Indexed: 11/28/2022]
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Vadera S, Jehi L, Burgess RC, Shea K, Alexopoulos AV, Mosher J, Gonzalez-Martinez J, Bingaman W. Correlation between magnetoencephalography-based “clusterectomy” and postoperative seizure freedom. Neurosurg Focus 2013; 34:E9. [DOI: 10.3171/2013.4.focus1357] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
During the presurgical evaluation of patients with medically intractable focal epilepsy, a variety of noninvasive studies are performed to localize the hypothetical epileptogenic zone and guide the resection. Magnetoencephalography (MEG) is becoming increasingly used in the clinical realm for this purpose. No investigators have previously reported on coregisteration of MEG clusters with postoperative resection cavities to evaluate whether complete “clusterectomy” (resection of the area associated with MEG clusters) was performed or to compare these findings with postoperative seizure-free outcomes.
Methods
The authors retrospectively reviewed the charts and imaging studies of 65 patients undergoing MEG followed by resective epilepsy surgery from 2009 until 2012 at the Cleveland Clinic. Preoperative MEG studies were fused with postoperative MRI studies to evaluate whether clusters were within the resected area. These data were then correlated with postoperative seizure freedom.
Results
Sixty-five patients were included in this study. The average duration of follow-up was 13.9 months, the mean age at surgery was 23.1 years, and the mean duration of epilepsy was 13.7 years. In 30 patients, the main cluster was located completely within the resection cavity, in 28 it was completely outside the resection cavity, and in 7 it was partially within the resection cavity. Seventy-four percent of patients were seizure free at 12 months after surgery, and this rate decreased to 60% at 24 months. Improved likelihood of seizure freedom was seen with complete clusterectomy in patients with localization outside the temporal lobe (extra–temporal lobe epilepsy) (p = 0.04).
Conclusions
In patients with preoperative MEG studies that show clusters in surgically accessible areas outside the temporal lobe, we suggest aggressive resection to improve the chances for seizure freedom. When the cluster is found within the temporal lobe, further diagnostic testing may be required to better localize the epileptogenic zone.
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Affiliation(s)
| | - Lara Jehi
- 2Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | | | - Katherine Shea
- 2Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | | | - John Mosher
- 2Epilepsy Center, Cleveland Clinic Foundation, Cleveland, Ohio
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Wu XT, Rampp S, Buchfelder M, Kuwert T, Blümcke I, Dörfler A, Zhou D, Stefan H. Interictal magnetoencephalography used in magnetic resonance imaging-negative patients with epilepsy. Acta Neurol Scand 2013; 127:274-80. [PMID: 22882005 DOI: 10.1111/j.1600-0404.2012.01712.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2012] [Indexed: 02/05/2023]
Abstract
PURPOSE This study aims to investigate the contributions of magnetoencephalography (MEG) in magnetic resonance imaging (MRI)-negative patients. METHODS A total of 18 MRI-negative patients diagnosed with refractory epilepsy, subjected to MEG investigation, and subsequently underwent surgery were selected for retrospective analysis. A 1.5-tesla Magnetom Sonata with an eight-channel head array coil was used. MEG data were obtained using a 74/248-channel system. RESULTS A total of 16 patients (16/18) had positive MEG results, comprising 12 patients with monofocal localizations, five with multifocal localizations, and one with unremarkable results in MEG. In addition, 12 patients had indicative single photon-emission computed tomography (SPECT), five had indicative fluorodeoxyglucose positron emission tomography (FDG-PET), and all the patients had intracranial electroencephalography (EEG) (14 with subdural electrodes and four with electrocorticography). The intracranial EEG recordings of nine patients were guided by MEG informative results. Among these 18 patients, 10 exhibited good postoperative outcomes (Engel I and II), four of which were completely seizure-free. All these ten patients had clear monofocal localization in MEG, including nine with accordant indicative metabolic changes in either SPECT or FDG-PET, or both. None of the five patients with multifocal localizations achieved good postoperative outcomes. CONCLUSION For cases with negative MRI findings, epilepsy surgery may be an alternative option for pharmaco-resistant patients if epileptogenic focus localizations by MEG are present in multimodal evaluation.
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Affiliation(s)
| | - S. Rampp
- Neurological Clinic; University Hospital Erlangen; Erlangen; Germany
| | - M. Buchfelder
- Department of Neurosurgery; University Hospital Erlangen; Erlangen; Germany
| | - T. Kuwert
- Department of Nuclear medicine; University Hospital Erlangen; Erlangen; Germany
| | - I. Blümcke
- Department of Neuropathology; University Hospital Erlangen; Erlangen; Germany
| | - A. Dörfler
- Department of Neuroradiology; University Hospital Erlangen; Erlangen; Germany
| | - D. Zhou
- Department of Neurology; West China Hospital; Sichuan University; Chengdu; Sichuan; China
| | - H. Stefan
- Neurological Clinic; University Hospital Erlangen; Erlangen; Germany
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Abstract
Mesial frontal lobe epilepsies can be divided into epilepsies arising from the anterior cingulate gyrus and those of the supplementary sensorimotor area. They provide diagnostic challenges because they often lack lateralizing or localizing features on clinical semiology and interictal and ictal scalp electroencephalographic (EEG) recordings. A number of unique semiologic features have been described over the last decade in patients with mesial frontal lobe epilepsy (FLE). There are few reports of applying advanced neurophysiologic techniques such as electrical source imaging, magnetoencephalography, EEG/functional magnetic resonance imaging, or analysis of high-frequency oscillations in patients with mesial FLE. Despite these diagnostic challenges, it seems that patients with mesial FLE benefit from epilepsy surgery to the same extent or even better than patients with FLE do, as a whole.
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Wu XT, Rampp S, Hopfengärtner R, Buchfelder M, Zhou D, Stefan H. Complementary use of video-electroencephalography and magnetoencephalography in frontal lobe epilepsy. Seizure 2012; 21:426-30. [DOI: 10.1016/j.seizure.2012.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 04/19/2012] [Accepted: 04/20/2012] [Indexed: 11/28/2022] Open
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Yasuda CL, Cendes F. Neuroimaging for the prediction of response to medical and surgical treatment in epilepsy. ACTA ACUST UNITED AC 2012; 6:295-308. [PMID: 23480740 DOI: 10.1517/17530059.2012.683408] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Approximately 30% of patients with epilepsy do not respond to adequate medication and are candidates for surgical treatment. Outcome predictors can improve the selection of more suitable treatment options for each patient. Therefore, the authors aimed to review the role of neuroimaging studies in predicting outcomes for both clinical and surgical treatment of epilepsy. AREAS COVERED This review analyzes studies that investigated different neuroimaging techniques as predictors of clinical and surgical treatment outcome in epilepsy. Studies involving both structural (i.e., T1-weighted images and diffusion tensor images) and functional MRI (fMRI) were identified, as well as other modalities such as spectroscopy, PET, SPECT and MEG. The authors also evaluated the importance of fMRI in predicting memory outcome after surgical resections in temporal lobe epilepsy. EXPERT OPINION The identification of reliable biomarkers to predict response to medical and surgical treatments are much needed in order to provide more adequate patient counseling about prognosis and treatment options individually. Different neuroimaging techniques may provide combined measurements that potentially may become these biomarkers in the near future.
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Affiliation(s)
- Clarissa Lin Yasuda
- University of Campinas/UNICAMP, Department of Neurology, Neuroimaging Laboratory , Cidade Universitária Zeferino Vaz, Rua Tessália Vieira de Camargo, 126. Cx postal 6111, Campinas, SP. CEP 13083-970 , Brazil
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