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Shi LJ, Li CC, Zhang XT, Lin YC, Wang YP, Zhang JC. Application of HFO and scaling analysis of neuronal oscillations in the presurgical evaluation of focal epilepsy. Brain Res Bull 2024; 215:111018. [PMID: 38908759 DOI: 10.1016/j.brainresbull.2024.111018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/07/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
PURPOSE To explore the utility of high frequency oscillations (HFO) and long-range temporal correlations (LRTCs) in preoperative assessment of epilepsy. METHODS MEG ripples were detected in 59 drug-resistant epilepsy patients, comprising 5 with parietal lobe epilepsy (PLE), 21 with frontal lobe epilepsy (FLE), 14 with lateral temporal lobe epilepsy (LTLE), and 19 with mesial temporal lobe epilepsy (MTLE) to identify the epileptogenic zone (EZ). The results were compared with clinical MEG reports and resection area. Subsequently, LRTCs were quantified at the source-level by detrended fluctuation analysis (DFA) and life/waiting -time at 5 bands for 90 cerebral cortex regions. The brain regions with larger DFA exponents and standardized life-waiting biomarkers were compared with the resection results. RESULTS Compared to MEG sensor-level data, ripple sources were more frequently localized within the resection area. Moreover, source-level analysis revealed a higher proportion of DFA exponents and life-waiting biomarkers with relatively higher rankings, primarily distributed within the resection area (p<0.01). Moreover, these two LRCT indices across five distinct frequency bands correlated with EZ. CONCLUSION HFO and source-level LRTCs are correlated with EZ. Integrating HFO and LRTCs may be an effective approach for presurgical evaluation of epilepsy.
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Affiliation(s)
- Li-Juan Shi
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; Beijing Advanced Innovation Centre for Big Data-Based Precision Medicine, Beihang University, Beijing, China; Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Can-Cheng Li
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; Beijing Advanced Innovation Centre for Big Data-Based Precision Medicine, Beihang University, Beijing, China; Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Xia-Ting Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Brain Functional Disease and Neuromodulation of Beijing Key Laboratory, Beijing 100053, China
| | - Yi-Cong Lin
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Brain Functional Disease and Neuromodulation of Beijing Key Laboratory, Beijing 100053, China
| | - Yu-Ping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Brain Functional Disease and Neuromodulation of Beijing Key Laboratory, Beijing 100053, China.
| | - Ji-Cong Zhang
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; Beijing Advanced Innovation Centre for Big Data-Based Precision Medicine, Beihang University, Beijing, China; Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China; Hefei Innovation Research Institute, Beihang University, Hefei, Anhui, China.
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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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Chen JS, Lamoureux AA, Shlobin NA, Elkaim LM, Wang A, Ibrahim GM, Obaid S, Harroud A, Guadagno E, Dimentberg E, Bouthillier A, Bernhardt BC, Nguyen DK, Fallah A, Weil AG. Magnetic resonance-guided laser interstitial thermal therapy for drug-resistant epilepsy: A systematic review and individual participant data meta-analysis. Epilepsia 2023; 64:1957-1974. [PMID: 36824029 DOI: 10.1111/epi.17560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/30/2023] [Accepted: 02/22/2023] [Indexed: 02/25/2023]
Abstract
Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a popular minimally invasive alternative to open resective surgery for drug-resistant epilepsy (DRE). We sought to perform a systematic review and individual participant data meta-analysis to identify independent predictors of seizure outcome and complications following MRgLITT for DRE. Eleven databases were searched from January 1, 2010 to February 6, 2021 using the terms "MR-guided ablation therapy" and "epilepsy". Multivariable mixed-effects Cox and logistic regression identified predictors of time to seizure recurrence, seizure freedom, operative complications, and postoperative neurological deficits. From 8705 citations, 46 studies reporting on 450 MRgLITT DRE patients (mean age = 29.5 ± 18.1 years, 49.6% female) were included. Median postoperative seizure freedom and follow-up duration were 15.5 and 19.0 months, respectively. Overall, 240 (57.8%) of 415 patients (excluding palliative corpus callosotomy) were seizure-free at last follow-up. Generalized seizure semiology (hazard ratio [HR] = 1.78, p = .020) and nonlesional magnetic resonance imaging (MRI) findings (HR = 1.50, p = .032) independently predicted shorter time to seizure recurrence. Cerebral cavernous malformation (CCM; odds ratio [OR] = 7.97, p < .001) and mesial temporal sclerosis/atrophy (MTS/A; OR = 2.21, p = .011) were independently associated with greater odds of seizure freedom at last follow-up. Operative complications occurred in 28 (8.5%) of 330 patients and were independently associated with extratemporal ablations (OR = 5.40, p = .012) and nonlesional MRI studies (OR = 3.25, p = .017). Postoperative neurological deficits were observed in 53 (15.1%) of 352 patients and were independently predicted by hypothalamic hamartoma etiology (OR = 5.93, p = .006) and invasive electroencephalographic monitoring (OR = 4.83, p = .003). Overall, MRgLITT is particularly effective in treating patients with well-circumscribed lesional DRE, such as CCM and MTS/A, but less effective in nonlesional cases or lesional cases with a more diffuse epileptogenic network associated with generalized seizures. This study identifies independent predictors of seizure freedom and complications following MRgLITT that may help further guide patient selection.
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Affiliation(s)
- Jia-Shu Chen
- Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Audrey-Anne Lamoureux
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada
| | - Nathan A Shlobin
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Lior M Elkaim
- Division of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Andrew Wang
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - George M Ibrahim
- Division of Neurosurgery, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Sami Obaid
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada
- Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada
| | - Adil Harroud
- Division of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Elena Guadagno
- Harvey E. Beardmore Division of Pediatric Surgery, McGill University Health Center, Montreal, Quebec, Canada
| | - Evan Dimentberg
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada
- Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Alain Bouthillier
- Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada
| | - Boris C Bernhardt
- McConnell Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Dang K Nguyen
- Division of Neurology, University of Montreal Medical Center, Montreal, Quebec, Canada
| | - Aria Fallah
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Alexander G Weil
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada
- Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada
- Brain and Child Development Axis, Sainte Justine Research Center, Montreal, Quebec, Canada
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Prognostic value of high-frequency oscillations combined with multimodal imaging methods for epilepsy surgery. Chin Med J (Engl) 2021; 135:1087-1095. [PMID: 35773966 PMCID: PMC9276102 DOI: 10.1097/cm9.0000000000001909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background: The combination of high-frequency oscillations (HFOs) with single-mode imaging methods has been proved useful in identifying epileptogenic zones, whereas few studies have examined HFOs combined with multimodal imaging methods. The aim of this study was to evaluate the prognostic value of ripples, an HFO subtype with a frequency of 80 to 200 Hz is combined with multimodal imaging methods in predicting epilepsy surgery outcome. Methods: HFOs were analyzed in 21 consecutive medically refractory epilepsy patients who underwent epilepsy surgery. All patients underwent positron emission tomography (PET) and deep electrode implantation for stereo-electroencephalography (SEEG); 11 patients underwent magnetoencephalography (MEG). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting surgical outcome were calculated for ripples combined with PET, MEG, both PET and MEG, and PET combined with MEG. Kaplan-Meier survival analyses were conducted in each group to estimate prognostic value. Results: The study included 13 men and 8 women. Accuracy for ripples, PET, and MEG alone in predicting surgical outcome was 42.9%, 42.9%, and 81.8%, respectively. Accuracy for ripples combined with PET and MEG was the highest. Resection of regions identified by ripples, MEG dipoles, and combined PET findings was significantly associated with better surgical outcome (P < 0.05). Conclusions: Intracranial electrodes are essential to detect regions which generate ripples and to remove these areas which indicate good surgical outcome for medically intractable epilepsy. With the assistance of presurgical noninvasive imaging examinations, PET and MEG, for example, the SEEG electrodes would identify epileptogenic regions more effectively.
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Watkins MW, Shah EG, Funke ME, Garcia-Tarodo S, Shah MN, Tandon N, Maestu F, Laohathai C, Sandberg DI, Lankford J, Thompson S, Mosher J, Von Allmen G. Indications for Inpatient Magnetoencephalography in Children - An Institution's Experience. Front Hum Neurosci 2021; 15:667777. [PMID: 34149382 PMCID: PMC8213217 DOI: 10.3389/fnhum.2021.667777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 04/14/2021] [Indexed: 11/13/2022] Open
Abstract
Magnetoencephalography (MEG) is recognized as a valuable non-invasive clinical method for localization of the epileptogenic zone and critical functional areas, as part of a pre-surgical evaluation for patients with pharmaco-resistant epilepsy. MEG is also useful in localizing functional areas as part of pre-surgical planning for tumor resection. MEG is usually performed in an outpatient setting, as one part of an evaluation that can include a variety of other testing modalities including 3-Tesla MRI and inpatient video-electroencephalography monitoring. In some clinical circumstances, however, completion of the MEG as an inpatient can provide crucial ictal or interictal localization data during an ongoing inpatient evaluation, in order to expedite medical or surgical planning. Despite well-established clinical indications for performing MEG in general, there are no current reports that discuss indications or considerations for completion of MEG on an inpatient basis. We conducted a retrospective institutional review of all pediatric MEGs performed between January 2012 and December 2020, and identified 34 cases where MEG was completed as an inpatient. We then reviewed all relevant medical records to determine clinical history, all associated diagnostic procedures, and subsequent treatment plans including epilepsy surgery and post-surgical outcomes. In doing so, we were able to identify five indications for completing the MEG on an inpatient basis: (1) super-refractory status epilepticus (SRSE), (2) intractable epilepsy with frequent electroclinical seizures, and/or frequent or repeated episodes of status epilepticus, (3) intractable epilepsy with infrequent epileptiform discharges on EEG or outpatient MEG, or other special circumstances necessitating inpatient monitoring for successful and safe MEG data acquisition, (4) MEG mapping of eloquent cortex or interictal spike localization in the setting of tumor resection or other urgent neurosurgical intervention, and (5) international or long-distance patients, where outpatient MEG is not possible or practical. MEG contributed to surgical decision-making in the majority of our cases (32 of 34). Our clinical experience suggests that MEG should be considered on an inpatient basis in certain clinical circumstances, where MEG data can provide essential information regarding the localization of epileptogenic activity or eloquent cortex, and be used to develop a treatment plan for surgical management of children with complicated or intractable epilepsy.
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Affiliation(s)
- Michael W Watkins
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States
| | - Ekta G Shah
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States
| | - Michael E Funke
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States.,Department of Neurology, McGovern Medical School, Houston, TX, United States
| | - Stephanie Garcia-Tarodo
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States.,Pediatric Neurology Unit, Children's Hospital, Geneva University Hospitals, Geneva, Switzerland
| | - Manish N Shah
- Department of Neurosurgery, McGovern Medical School, Houston, TX, United States.,Division of Pediatric Neurosurgery, Department of Pediatric Surgery, McGovern Medical School, Houston, TX, United States
| | - Nitin Tandon
- Department of Neurosurgery, McGovern Medical School, Houston, TX, United States
| | - Fernando Maestu
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States.,Laboratory of Cognitive and Computational Neuroscience, Center for Biomedical Technology, Universidad Complutense and Universidad Politecnica de Madrid, Madrid, Spain.,Department of Experimental Psychology, Universidad Complutense de Madrid, Madrid, Spain
| | - Christopher Laohathai
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States
| | - David I Sandberg
- Department of Neurosurgery, McGovern Medical School, Houston, TX, United States.,Division of Pediatric Neurosurgery, Department of Pediatric Surgery, McGovern Medical School, Houston, TX, United States
| | - Jeremy Lankford
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States
| | - Stephen Thompson
- Department of Neurology, McGovern Medical School, Houston, TX, United States
| | - John Mosher
- Department of Neurology, McGovern Medical School, Houston, TX, United States
| | - Gretchen Von Allmen
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX, United States.,Department of Neurology, McGovern Medical School, Houston, TX, United States
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Gautham B, Abdulhak A, Mundlamuri RC, Narayanan M, Jayabal V, Kenchaiah R, Asranna A, Dawn BR, Jitender S, Nagaraj C, Mangalore S, Karthik K, Sadashiva N, Mahadevan A, Rajeswaran J, Kumar K, Arivazhagan A, Rao MB, Sinha S. Magnetic source imaging in presurgical evaluation of paediatric focal drug-resistant epilepsy and its predictive value of surgical outcome in lesional cases: A single-centre experience from South India. Seizure 2021; 91:22-28. [PMID: 34058605 DOI: 10.1016/j.seizure.2021.05.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE This study aims to evaluate the utility of magnetoencephalography in presurgical planning and in predicting post-surgical seizure outcome. METHODS This study included a cohort of 231 children (1-18 years) with focal drug-resistant epilepsy who underwent MEG as a part of their presurgical workup. Characteristics of MEG observations were described in all children. The concordance and agreement of Magnetic Source Imaging (MSI) of interictal discharges (IED) was estimated with either of the 3 subgroups - MRI lesion; presumed epileptogenic zone (EZ); or resection cavity. In operated children group, MEG dipole characteristics between good and poor outcome groups were assessed. RESULTS A total of 153 cases (66.2%) showed frequent IEDs (60 spikes/60 min). Of the 173 cases where MSI showed clusters (74.9%), 151 had lesions and 22 were non-lesional. amongst patients with lesional epilepsy and MEG clusters, class I concordance (MEG localization either completely included or overlapped at least 60% with the MRI lesion) was seen in 60.92% with a Cohen's kappa of 0.608. In non-lesional epilepsy, class I concordance of MEG with presumed EZ was found in (81.81%) with an agreement of 0.317. Fifty-three children underwent surgery of whom 39 (73.58%) showed a good outcome (Engel I). In operated children, concordance between MEG focus and resection cavity was observed in 23 (58.97%) with good outcome and in 12 (86.72%) with poor outcome with no significant difference (p>0.05). However, MEG cluster regular organization and clusterectomy are associated with good seizure outcome postoperatively (p< 0.05). Presence of scatters were associated with poor outcome (p<0.05) in children with focal cortical dysplasia. CONCLUSIONS MEG provides useful information that can serve as a biomarker for prognosticating the surgical outcome in paediatric epilepsy. Cluster removal and regular cluster organization shows predictive power in post-surgical prognostication in children and the presence of scatters predicts poor outcome in children with focal cortical dysplasia.
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Affiliation(s)
- Bhargava Gautham
- MEG research Centre, NIMHANS, Hosur Road, Bangalore, India; Department of Neurology, NIMHANS, Hosur Road, Bangalore, India
| | - Asheeb Abdulhak
- Department of Neurology, NIMHANS, Hosur Road, Bangalore, India
| | | | - Mariyappa Narayanan
- MEG research Centre, NIMHANS, Hosur Road, Bangalore, India; Department of Neurology, NIMHANS, Hosur Road, Bangalore, India
| | | | | | - Ajay Asranna
- Department of Neurology, NIMHANS, Hosur Road, Bangalore, India
| | - Bharath Rose Dawn
- Department of Neuroimaging and Interventional Radiology, NIMHANS, Hosur Road, Bangalore, India
| | - Saini Jitender
- Department of Neuroimaging and Interventional Radiology, NIMHANS, Hosur Road, Bangalore, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology, NIMHANS, Hosur Road, Bangalore, India
| | - Sandhya Mangalore
- Department of Neuroimaging and Interventional Radiology, NIMHANS, Hosur Road, Bangalore, India
| | - Kulanthaivelu Karthik
- Department of Neuroimaging and Interventional Radiology, NIMHANS, Hosur Road, Bangalore, India
| | | | - Anita Mahadevan
- Department of Neuropathology, NIMHANS, Hosur Road, Bangalore, India
| | - Jamuna Rajeswaran
- Department of Clinical Psychology, NIMHANS, Hosur Road, Bangalore, India
| | - Keshav Kumar
- Department of Clinical Psychology, NIMHANS, Hosur Road, Bangalore, India
| | | | | | - Sanjib Sinha
- MEG research Centre, NIMHANS, Hosur Road, Bangalore, India; Department of Neurology, NIMHANS, Hosur Road, Bangalore, India.
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7
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Kuzan-Fischer CM, Parker WE, Schwartz TH, Hoffman CE. Challenges of Epilepsy Surgery. World Neurosurg 2020; 139:762-774. [PMID: 32689697 DOI: 10.1016/j.wneu.2020.03.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/02/2020] [Indexed: 12/22/2022]
Abstract
Though frequently effective in the management of medically refractory seizures, epilepsy surgery presents numerous challenges. Selection of the appropriate candidate patients who are likely to benefit from surgery is critical to achieving seizure freedom and avoiding neurocognitive morbidity. Identifying the seizure focus and mapping epileptogenic networks involves an interdisciplinary team dedicated to formulating a safe and effective surgical plan. Various strategies can be employed either to eliminate the epileptic focus or to modulate network activity, including resection of the focus with open surgery or laser interstitial thermal therapy; modulation of epileptogenic firing patterns with responsive neurostimulation, deep brain stimulation, or vagus nerve stimulation; or non-invasive disconnection of epileptic circuits with focused ultrasound, which is also discussed in greater detail in the subsequent chapter in our series. We review several challenges of epilepsy surgery that must be thoughtfully addressed in order to ensure its success.
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Affiliation(s)
- Claudia M Kuzan-Fischer
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Whitney E Parker
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Caitlin E Hoffman
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA.
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8
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Gao R, Yu T, Xu C, Zhang X, Yan X, Ni D, Zhang X, Ma K, Qiao L, Zhu J, Wang X, Ren Z, Zhang X, Zhang G, Li Y. The value of magnetoencephalography for stereo-EEG-guided radiofrequency thermocoagulation in MRI-negative epilepsy. Epilepsy Res 2020; 163:106322. [PMID: 32278277 DOI: 10.1016/j.eplepsyres.2020.106322] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/24/2020] [Accepted: 03/19/2020] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Magnetoencephalography (MEG) is valuable for guiding resective surgery in patients with epilepsy. However, its value for minimally invasive treatment is still unknown. This study aims to evaluate the value of MEG for stereo-electroencephalogram (EEG)-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in magnetic resonance imaging (MRI)-negative epilepsies. METHODS An observational cohort study was performed and 19 MRI-negative patients who underwent SEEG-guided RF-TC in our epilepsy center were included. In addition, 16 MRI-positive patients were included as a reference group. Semiology, electrophysiology, and imaging information were collected. To evaluate the value of locating the MEG cluster, the proportion of the RF-TC contacts located in the MEG cluster out of all contacts used to perform RF-TC in each patient was calculated. All patients underwent the standard SEEG-guided RF-TC procedure and were followed up after the treatment. RESULTS Nineteen MRI-negative patients were divided into two groups based on the existence of MEG clusters; 10 patients with MEG clusters were in group I and nine patients without any MEG cluster were in group II. No significant difference was observed in terms of age, sex, type of seizures, or number of SEEG electrodes implanted. The median of the proportion of contacts in the MEG cluster was 77.0 % (IQR 57.7-100.0 %). The follow-up results showed that the probability of being seizure-free at one year after RFTC in MRI-negative patients with an MEG cluster was 30.0 % (95 % CI 11.6-77.3 %), significantly (p = 0.014) higher than that in patients without an MEG cluster; there was no significant difference when compared with MRI-positive patients. CONCLUSION This is the first study to evaluate the value of MEG in SEEG-guided RF-TC in MRI-negative epilepsies. MEG is a useful supplement for patients with MRI-negative epilepsy. MEG can be applied in minimally invasive treatment. MEG clusters can help identify better candidates and provide a valuable target for SEEG-guided RF-TC, which leads to better outcomes.
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Affiliation(s)
- Runshi Gao
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Tao Yu
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Cuiping Xu
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiating Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaoming Yan
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Duanyu Ni
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaohua Zhang
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kai Ma
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Liang Qiao
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jin Zhu
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xueyuan Wang
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zhiwei Ren
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xi Zhang
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Guojun Zhang
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yongjie Li
- Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
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9
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Magnetoencephalographic Recordings in Infants: A Retrospective Analysis of Seizure-Focus Yield and Postsurgical Outcomes. J Clin Neurophysiol 2018; 35:454-462. [PMID: 30004913 DOI: 10.1097/wnp.0000000000000500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Magnetoencephalography (MEG) is often incorporated into the presurgical work-up of children with pharmacoresistant epilepsy. There is growing literature on its role in improving selection for epilepsy surgery, particularly when brain MRI is "non-lesional" or in patients with recurrence or intractable seizures after epilepsy surgery. There are, however, no reports on the extrapolation of its role in the presurgical decision-making process of infants. METHODS We performed a retrospective analysis of infants who underwent MEG over a 10-year period at our center for presurgical work-up. We reviewed medical records to ascertain seizure history, work-up procedures including brain MRI and scalp EEG, and in the case of surgery, intracranial recordings, operative notes, and follow-up outcomes. RESULTS We identified 31 infants (<2 years of age) who underwent MEG recordings. Despite EEG interictal readings showing patterns of generalized dysfunction in 80%, MEG was able to pinpoint the foci of epileptic activity in 45%. In the MRI-negative group, 44% had focal lateralized interictal spikes on MEG. The sensitivity of MEG to detect interictal epileptiform activity was 90%, and its ability to provide additional information was 28%. Among 18 infants who had surgery, 13 became seizure free at follow-up. The percentage of infants with a focal spike volume on MEG studies and a seizure-free outcome was 66%. CONCLUSIONS MEG recordings in infants were found to be as sensitive for identifying seizure focus as other age groups, also supplying additional information to the decision-making process and validating its role in the presurgical work-up of infants with intractable epilepsy.
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The role of magnetoencephalography in the presurgical evaluation of patients with MRI-negative operculo-insular epilepsy. Seizure 2018; 61:104-110. [DOI: 10.1016/j.seizure.2018.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/30/2018] [Accepted: 07/08/2018] [Indexed: 10/28/2022] Open
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Pre-surgical mapping of eloquent cortex for paediatric epilepsy surgery candidates: Evidence from a review of advanced functional neuroimaging. Seizure 2017; 52:136-146. [DOI: 10.1016/j.seizure.2017.09.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/16/2017] [Accepted: 09/29/2017] [Indexed: 11/19/2022] Open
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Shukla G, Kazutaka J, Gupta A, Mosher J, Jones S, Alexopoulos A, Burgess RC. Magnetoencephalographic Identification of Epileptic Focus in Children With Generalized Electroencephalographic (EEG) Features but Focal Imaging Abnormalities. J Child Neurol 2017; 32:981-995. [PMID: 28828916 DOI: 10.1177/0883073817724903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE Children with generalized seizures are often excluded as epilepsy surgery candidates. This prospective study was conducted to evaluate the utility of magnetoencephalography (MEG) to refine the location of the "irritative zone" in children with single lesions on magnetic resonance imaging (MRI) but with generalized ictal electroencephalographic (EEG) findings. METHODS Patients admitted with refractory epilepsy with imaging studies showing focal or hemispheric abnormalities but scalp video EEG showing generalized or multiregional epileptiform abnormalities were included. Patients were encouraged into natural sleep, and simultaneous whole-head MEG/EEG was recorded. Source localization of epileptic spikes on MEG was carried out while blinded to other results. Acceptable dipoles were classified into 3 groups: focal, hemispheric clusters, and single focal cluster with additional widespread dipoles. RESULTS Nine patients (4 female, 5 males; ages 10 months to 15 years) were included. Two had focal features on clinical semiology, whereas all had generalized or multiregional interictal and ictal EEG. Etiologies included tuberous sclerosis complex (2), postencephalitic sequelae (1), focal cortical dysplasia (1), and unknown (2). Five patients had clear focal lesions on brain MRI whereas the other 2 had focal positron emission tomography (PET) abnormalities. An average of 38 spikes were accepted (average goodness of fit = 85.3%). A single tight cluster of dipoles was identified in 5 patients, 1 had dipoles with propagation from left occipital to right temporal. One patient had 2 distinct dipole clusters. MEG demonstrated focal findings 9 times more often than the simultaneously recorded scalp EEG, and 3 times more often than the associated multiday video EEG recordings. CONCLUSION This study shows that neurophysiologic evidence of focal epileptiform abnormalities in patients with focal brain lesions and generalized EEG findings can be strengthened using MEG. Further feasibility of surgical candidacy should be evaluated in these patients.
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Affiliation(s)
- Garima Shukla
- 1 Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA.,2 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Jin Kazutaka
- 1 Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA.,3 Department of Epileptology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Ajay Gupta
- 1 Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA
| | - John Mosher
- 1 Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA
| | - Stephen Jones
- 1 Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, USA
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Magnetoencephalographic Recordings in Infants Using a Standard-Sized Array. J Clin Neurophysiol 2017; 34:461-468. [DOI: 10.1097/wnp.0000000000000400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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14
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Timoney N, Rutka JT. Recent Advances in Epilepsy Surgery and Achieving Best Outcomes Using High-Frequency Oscillations, Diffusion Tensor Imaging, Magnetoencephalography, Intraoperative Neuromonitoring, Focal Cortical Dysplasia, and Bottom of Sulcus Dysplasia. Neurosurgery 2017; 64:1-10. [DOI: 10.1093/neuros/nyx239] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/27/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nessa Timoney
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky, USA
- Department of Surgery, Division of Ne-urosurgery, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - James T. Rutka
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky, USA
- Department of Surgery, Division of Ne-urosurgery, The Hospital for Sick Children, University of Toronto, Toronto, Canada
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Bansal S, Kim AJ, Berg AT, Koh S, Laux LC, Nangia S, Millichap JJ, Shaw A, Fisher B, Dezort C, DiPatri AJ, Alden TD, Nordli DR. Seizure Outcomes in Children Following Electrocorticography-Guided Single-Stage Surgical Resection. Pediatr Neurol 2017; 71:35-42. [PMID: 28483395 DOI: 10.1016/j.pediatrneurol.2017.01.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/13/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND In children with abnormal imaging, single-stage epilepsy surgery is an attractive alternative to the two-stage approach that relies on invasive recording of seizures. Implanted electrodes carry risks of their own and extend hospitalization, but the efficacy of one-stage resections in a variety of pathologies and cerebral locations is not well established. We report our center's experience with single-stage epilepsy surgery guided by intraoperative electrocorticography (ECoG). METHODS We retrospectively analyzed 130 consecutive patients who underwent single-stage epilepsy surgery before age 19 years and had at least a two-year follow-up. Intraoperative ECoG was available for review in 113. Patients were considered seizure-free if they were continuously Engel Class I up to the two-year postoperative mark. ECoG findings were classified according to the presence of interictal attenuation, spikes, both, or neither. Complications and hospital length of stay were evaluated. RESULTS Eighty percent of 130 patients were seizure-free at two years. All but one had an abnormal MRI. Patients with tumor had a better seizure outcome than patients with cortical malformation. Frontal resections had worse outcome, especially among tumors. Intraoperative ECoG revealed both attenuation and spikes in 48%, attenuation only in 23%, spikes only in 20%, and neither in 9%. The complication rate was 6.9%, with no major neurological complications. The average length of stay was 5.7 nights. CONCLUSIONS With ECoG-guided single-stage surgery, we achieved results comparable with other pediatric surgical series and with a low complication rate. An extensive two-stage approach may not be required when there is a lesion on imaging and other information is concordant, even when the MRI abnormality is subtle and unclearly delineated. Frontal foci may present a challenge because of their proximity to "eloquent" nonresectable cortex or critical structures.
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Affiliation(s)
- Seema Bansal
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Andrew J Kim
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
| | - Anne T Berg
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Sookyong Koh
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Linda C Laux
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Srishti Nangia
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - John J Millichap
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Alexandra Shaw
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Breanne Fisher
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Catherine Dezort
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Arthur J DiPatri
- Department of Neurological Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Tord D Alden
- Department of Neurological Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Douglas R Nordli
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Warsi NM, Lasry O, Farah A, Saint-Martin C, Montes JL, Atkinson J, Farmer JP, Dudley RWR. 3-T intraoperative MRI (iMRI) for pediatric epilepsy surgery. Childs Nerv Syst 2016; 32:2415-2422. [PMID: 27757571 DOI: 10.1007/s00381-016-3263-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
Abstract
PURPOSE Three-tesla intraoperative MRI (iMRI) is a promising tool that could help confirm complete resections and disconnections in pediatric epilepsy surgery, leading to improved outcomes. However, a large proportion of epileptogenic pathologies in children are poorly defined on imaging, which brings into question the utility of iMRI for these cases. Our aim was to compare postoperative seizure outcomes between iMRI- and non-iMRI-based epilepsy surgeries. METHODS We performed a comparative retrospective analysis of non-iMRI- versus iMRI-based epilepsy surgeries with 2-year follow-up. Patients were stratified into well-defined cases (WDCs), poorly defined cases (PDCs), and diffuse hemispheric cases (DHCs). Primary outcomes were rates of complete seizure freedom and surgical complications. Secondary outcomes included good (Engel class I/II) seizure outcome, extent of resection/disconnection, and operative duration. Regression models were used to adjust for confounding. RESULTS Thirty-nine iMRI-based and 39 non-iMRI-based surgeries were included. The distributions of age, sex, and lesion class in each era were similar, but the distributions of individual pathologies varied. Seizure freedom and complication rates at 2-year follow-up were not different between the groups, but Engel class I/II outcome was more common in the iMRI group. Extent of resection/disconnection and length of surgery were similar in both groups. PDCs had the worst outcomes, which were unchanged by the use of iMRI. CONCLUSION Three-tesla iMRI-based epilepsy surgery may have the potential to improve patient outcomes. However, we conclude that iMRI, in its current state of use at our institute, does not improve outcomes for children undergoing epilepsy surgery. Given that its use appears safe, further research on this technology is warranted, particularly for the most challenging PDCs.
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Affiliation(s)
- Nebras M Warsi
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Oliver Lasry
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada. .,Department of Epidemiology, Biostatistics and Occupational Health, Faculty of Medicine, McGill University, 1020 Pine Avenue West, Montréal, QC, H3A 1A2, Canada.
| | - Adel Farah
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Christine Saint-Martin
- Department of Medical Imaging, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jose L Montes
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jeffrey Atkinson
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jean-Pierre Farmer
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Roy W R Dudley
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
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Pang EW, Snead III OC. From Structure to Circuits: The Contribution of MEG Connectivity Studies to Functional Neurosurgery. Front Neuroanat 2016; 10:67. [PMID: 27445705 PMCID: PMC4914570 DOI: 10.3389/fnana.2016.00067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/07/2016] [Indexed: 11/14/2022] Open
Abstract
New advances in structural neuroimaging have revealed the intricate and extensive connections within the brain, data which have informed a number of ambitious projects such as the mapping of the human connectome. Elucidation of the structural connections of the brain, at both the macro and micro levels, promises new perspectives on brain structure and function that could translate into improved outcomes in functional neurosurgery. The understanding of neuronal structural connectivity afforded by these data now offers a vista on the brain, in both healthy and diseased states, that could not be seen with traditional neuroimaging. Concurrent with these developments in structural imaging, a complementary modality called magnetoencephalography (MEG) has been garnering great attention because it too holds promise for being able to shed light on the intricacies of functional brain connectivity. MEG is based upon the elemental principle of physics that an electrical current generates a magnetic field. Hence, MEG uses highly sensitive biomagnetometers to measure extracranial magnetic fields produced by intracellular neuronal currents. Put simply then, MEG is a measure of neurophysiological activity, which captures the magnetic fields generated by synchronized intraneuronal electrical activity. As such, MEG recordings offer exquisite resolution in the time and oscillatory domain and, as well, when co-registered with magnetic resonance imaging (MRI), offer excellent resolution in the spatial domain. Recent advances in MEG computational and graph theoretical methods have led to studies of connectivity in the time-frequency domain. As such, MEG can elucidate a neurophysiological-based functional circuitry that may enhance what is seen with MRI connectivity studies. In particular, MEG may offer additional insight not possible by MRI when used to study complex eloquent function, where the precise timing and coordination of brain areas is critical. This article will review the traditional use of MEG for functional neurosurgery, describe recent advances in MEG connectivity analyses, and consider the additional benefits that could be gained with the inclusion of MEG connectivity studies. Since MEG has been most widely applied to the study of epilepsy, we will frame this article within the context of epilepsy surgery and functional neurosurgery for epilepsy.
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Affiliation(s)
- Elizabeth W. Pang
- Division of Neurology, Hospital for Sick ChildrenToronto, ON, Canada
- Neurosciences and Mental Health, SickKids Research InstituteToronto, ON, Canada
- Department of Paediatrics, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - O. C. Snead III
- Division of Neurology, Hospital for Sick ChildrenToronto, ON, Canada
- Neurosciences and Mental Health, SickKids Research InstituteToronto, ON, Canada
- Department of Paediatrics, Faculty of Medicine, University of TorontoToronto, ON, Canada
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Ahmed R, Rutka JT. The role of MEG in pre-surgical evaluation of epilepsy: current use and future directions. Expert Rev Neurother 2016; 16:795-801. [DOI: 10.1080/14737175.2016.1181544] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Raheel Ahmed
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada
| | - James T. Rutka
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada
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O'Donovan CA. To do or not to do? Magnetoencephalography in the presurgical evaluation of epilepsy. Epilepsy Behav 2015; 46:8-9. [PMID: 25864993 DOI: 10.1016/j.yebeh.2015.02.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 02/16/2015] [Accepted: 02/20/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Cormac A O'Donovan
- Department of Neurology, Wake Forest University, Winston-Salem, NC 27157, USA.
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