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Noorizadeh N, Varner JA, Birg L, Williard T, Rezaie R, Wheless J, Narayana S. Comparing the efficacy of awake and sedated MEG to TMS in mapping hand sensorimotor cortex in a clinical cohort. Neuroimage Clin 2024; 41:103562. [PMID: 38215622 PMCID: PMC10821581 DOI: 10.1016/j.nicl.2024.103562] [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: 08/28/2023] [Revised: 11/19/2023] [Accepted: 01/07/2024] [Indexed: 01/14/2024]
Abstract
Non-invasive methods such as Transcranial Magnetic Stimulation (TMS) and magnetoencephalography (MEG) aid in the pre-surgical evaluation of patients with epilepsy or brain tumor to identify sensorimotor cortices. MEG requires sedation in children or patients with developmental delay. However, TMS can be applied to awake patients of all ages with any cognitive abilities. In this study, we compared the efficacy of TMS with MEG (in awake and sedated states) in identifying the hand sensorimotor areas in patients with epilepsy or brain tumors. We identified 153 patients who underwent awake- (n = 98) or sedated-MEG (n = 55), along with awake TMS for hand sensorimotor mapping as part of their pre-surgical evaluation. TMS involved stimulating the precentral gyrus and recording electromyography responses, while MEG identified the somatosensory cortex during median nerve stimulation. Awake-MEG had a success rate of 92.35 % and TMS had 99.49 % (p-value = 0.5517). However, in the sedated-MEG cohort, TMS success rate of 95.61 % was significantly higher compared to MEG's 58.77 % (p-value = 0.0001). Factors affecting mapping success were analyzed. Logistic regression across the entire cohort identified patient sedation as the lone significant predictor, contrary to age, lesion, metal, and number of antiseizure medications (ASMs). A subsequent analysis replaced sedation with anesthetic drug dosage, revealing no significant predictors impacting somatosensory mapping success under sedation. This study yields insights into the utility of TMS and MEG in mapping hand sensorimotor cortices and underscores the importance of considering factors that influence eloquent cortex mapping limitations during sedation.
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Affiliation(s)
- Negar Noorizadeh
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States; Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Jackie Austin Varner
- Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Liliya Birg
- Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Theresa Williard
- Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Roozbeh Rezaie
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States; Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - James Wheless
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States; Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Shalini Narayana
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States; Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, United States; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States.
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Hassanzadeh E, Hornak A, Hassanzadeh M, Warfield SK, Pearl PL, Bolton J, Suarez R, Stone S, Stufflebeam S, Ailion AS. Comparison of fMRI language laterality with and without sedation in pediatric epilepsy. Neuroimage Clin 2023; 38:103448. [PMID: 37285796 PMCID: PMC10250119 DOI: 10.1016/j.nicl.2023.103448] [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: 03/16/2023] [Revised: 05/07/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023]
Abstract
Functional MRI is an essential component of presurgical language mapping. In clinical settings, young children may be sedated for the MRI with the functional stimuli presented passively. Research has found that sedation changes language activation in healthy adults and children. However, there is limited research comparing sedated and unsedated functional MRI in pediatric epilepsy patients. We compared language activation patterns in children with epilepsy who received sedation for functional MRI to the ones who did not. We retrospectively identified the patients with focal epilepsy who underwent presurgical functional MRI including Auditory Descriptive Decision Task at Boston Children's Hospital from 2014 to 2022. Patients were divided into sedated and awake groups, based on their sedation status during functional MRI. Auditory Descriptive Decision Task stimuli were presented passively to the sedated group per clinical protocol. We extracted language activation maps contrasted against a control task (reverse speech) in the Frontal and Temporal language regions and calculated separate language laterality indexes for each region. We considered positive laterality indexes as left dominant, negative laterality indexes as right dominant, and absolute laterality indexes <0.2 as bilateral. We defined 2 language patterns: typical (i.e., primarily left-sided) and atypical. Typical pattern required at least one left dominant region (either frontal or temporal) and no right dominant region. We then compared the language patterns between the sedated and awake groups. Seventy patients met the inclusion criteria, 25 sedated, and 45 awake. Using the Auditory Descriptive Decision Task paradigm, when adjusted for age, handedness, gender, and laterality of lesion in a weighted logistic regression model, the odds of the atypical pattern were 13.2 times higher in the sedated group compared to the awake group (Confidence Interval: 2.55-68.41, p-value < 0.01). Sedation may alter language activation patterns in pediatric epilepsy patients. Language patterns on sedated functional MRI with passive tasks may not represent language networks during wakefulness, sedation may differentially suppress some networks, or require a different task or method of analysis to capture the awake language network. Given the critical surgical implication of these findings, additional studies are needed to better understand how sedation impacts the functional MRI blood oxygenation level-dependent signal. Consistent with current practice, sedated functional MRI should be interpreted with greater caution and requires additional validation as well as research on post-surgical language outcomes.
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Affiliation(s)
- Elmira Hassanzadeh
- Neuroradiology, Massachusetts General Hospital, Harvard Medical School, 02116, USA.
| | - Alena Hornak
- Neurology, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | | | - Simon K Warfield
- Radiology, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | - Phillip L Pearl
- Neurology, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | - Jeffrey Bolton
- Neurology, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | - Ralph Suarez
- Radiology, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | - Scellig Stone
- Neurosurgery, Boston Children's Hospital, Harvard Medical School, 02116, USA
| | - Steve Stufflebeam
- Neuroradiology, Massachusetts General Hospital, Harvard Medical School, 02116, USA
| | - Alyssa S Ailion
- Neurology, Boston Children's Hospital, Harvard Medical School, 02116, USA
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Mozaffari K, Hofmann K, Boyd P, Chalif E, Pasupuleti A, Gaillard WD, Oluigbo C. The Impact of Magnetoencephalography-Directed Stereo-Electroencephalography Depth Electrode Implantation on Seizure Control Outcome in Children. Cureus 2022; 14:e29860. [PMID: 36348878 PMCID: PMC9630048 DOI: 10.7759/cureus.29860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2022] [Indexed: 06/16/2023] Open
Abstract
Introduction The use of magnetoencephalography (MEG) in localizing epileptic foci and directing surgical treatment of medically refractory epilepsy is well established in clinical practice; however, it has not yet been incorporated into the routine planning of stereo-electroencephalography (EEG) (SEEG) depth electrode trajectories during invasive intracranial evaluation for epileptic foci localization. In this study, we assess the impact of MEG-directed SEEG on seizure outcomes in a pediatric cohort. Methods A retrospective analysis was performed on a single-institution cohort of pediatric patients with medically refractory epilepsy who underwent epilepsy surgery. The primary endpoint was the reduction in seizure burden as determined by dichotomized Engel scores (favorable outcome: Engel scores I and II; poor outcome: Engel scores III and IV). Results Thirty-seven patients met the inclusion criteria (24 males and 13 females). The median age at seizure onset was three years, the median age at surgery was 14.1 years, and the median follow-up length was 30.8 months. Concordance was noted in 7/10 (70%) patients who received MEG-directed SEEG. Good clinical outcomes were achieved in 70% of MEG-directed SEEG patients, compared to 59.4% in their counterparts; however, this difference was not statistically significant (p=0.72). We noted no statistically significant association between sex, disease laterality, or age at surgery and good clinical outcomes. Conclusions Patients who underwent MEG-directed SEEG had favorable clinical outcomes, which demonstrated the practicability of this technique for determining SEEG electrode placement. Although no significant difference in clinical outcomes was obtained between the two groups, this may have been due to low statistical power. Future prospective, multi-institutional investigations to assess the benefit of MEG-directed SEEG are warranted.
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Affiliation(s)
- Khashayar Mozaffari
- Department of Neurosurgery, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Katherine Hofmann
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
| | - Paul Boyd
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
| | - Eric Chalif
- Department of Neurosurgery, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Archana Pasupuleti
- Department of Neurology, Children's National Hospital, Washington, DC, USA
| | - William D Gaillard
- Department of Neurology, Children's National Hospital, Washington, DC, USA
| | - Chima Oluigbo
- Department of Neurosurgery, Children's National Hospital, Washington, DC, USA
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Beumer S, Boon P, Klooster DCW, van Ee R, Carrette E, Paulides MM, Mestrom RMC. Personalized tDCS for Focal Epilepsy—A Narrative Review: A Data-Driven Workflow Based on Imaging and EEG Data. Brain Sci 2022; 12:brainsci12050610. [PMID: 35624997 PMCID: PMC9139054 DOI: 10.3390/brainsci12050610] [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] [Received: 04/08/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
Conventional transcranial electric stimulation(tES) using standard anatomical positions for the electrodes and standard stimulation currents is frequently not sufficiently selective in targeting and reaching specific brain locations, leading to suboptimal application of electric fields. Recent advancements in in vivo electric field characterization may enable clinical researchers to derive better relationships between the electric field strength and the clinical results. Subject-specific electric field simulations could lead to improved electrode placement and more efficient treatments. Through this narrative review, we present a processing workflow to personalize tES for focal epilepsy, for which there is a clear cortical target to stimulate. The workflow utilizes clinical imaging and electroencephalography data and enables us to relate the simulated fields to clinical outcomes. We review and analyze the relevant literature for the processing steps in the workflow, which are the following: tissue segmentation, source localization, and stimulation optimization. In addition, we identify shortcomings and ongoing trends with regard to, for example, segmentation quality and tissue conductivity measurements. The presented processing steps result in personalized tES based on metrics like focality and field strength, which allow for correlation with clinical outcomes.
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Affiliation(s)
- Steven Beumer
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Correspondence:
| | - Paul Boon
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Debby C. W. Klooster
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Raymond van Ee
- Philips Research Eindhoven, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands;
| | - Evelien Carrette
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Maarten M. Paulides
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Burgemeester Oudlaan 50, 3062 PA Rotterdam, The Netherlands
| | - Rob M. C. Mestrom
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
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Clinical Speech fMRI in Children and Adolescents : Development of an Optimal Protocol and Analysis Algorithm. Clin Neuroradiol 2021; 32:185-196. [PMID: 34613421 PMCID: PMC8894226 DOI: 10.1007/s00062-021-01097-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
Purpose In patients with drug-resistant focal epilepsy, surgical resection is often the only treatment option to achieve long-term seizure control. Prior to brain surgery involving potential language areas, identification of hemispheric language dominance is crucial. Our group developed and validated a functional magnetic resonance imaging (fMRI) battery of four pediatric language tasks. The present study aimed at optimizing fMRI data acquisition and analysis using these tasks. Methods We retrospectively analyzed speech fMRI examinations of 114 neuropediatric patients (age range 5.8–17.8 years) who were examined prior to possible epilepsy surgery. In order to evaluate hemispheric language dominance, 1–4 language tasks (vowel identification task VIT, word-chain task WCT, beep-story task BST, synonym task SYT) were measured. Results Language dominance was classified using fMRI activation in the 13 validly lateralizing ROIs (VLR) in frontal, temporal and parietal lobes and cerebellum of the recent validation study from our group: 47/114 patients were classified as left-dominant, 34/114 as bilateral and 6/114 as right-dominant. In an attempt to enlarge the set of VLR, we then compared for each task agreement of these ROI activations with the classified language dominance. We found four additional task-specific ROIs showing concordant activation and activation in ≥ 10 sessions, which we termed validly lateralizing (VLRnew). The new VLRs were: for VIT the temporal language area and for SYT the middle frontal gyrus, the intraparietal sulcus and cerebellum. Finally, in order to find the optimal sequence of measuring the different tasks, we analyzed the success rates of single tasks and all possible task combinations. The sequence 1) VIT 2) WCT 3) BST 4) SYT was identified as the optimal sequence, yielding the highest chance to obtain reliable results even when the fMRI examination has to be stopped, e.g., due to lack of cooperation. Conclusion Our suggested task order together with the enlarged set of VLRnew may contribute to optimize pediatric speech fMRI in a clinical setting. Supplementary Information The online version of this article (10.1007/s00062-021-01097-z) contains supplementary material, which is available to authorized users.
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Koop JI, Credille K, Wang Y, Loman M, Marashly A, Kim I, Lew SM, Maheshwari M. Determination of language dominance in pediatric patients with epilepsy for clinical decision-making: Correspondence of intracarotid amobarbitol procedure and fMRI modalities. Epilepsy Behav 2021; 121:108041. [PMID: 34082317 DOI: 10.1016/j.yebeh.2021.108041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 11/29/2022]
Abstract
Identification of the language dominant hemisphere is an essential part of the evaluation of potential pediatric epilepsy surgery patients. Historically, language dominance has been determined using the intracarotid amobarbitol procedure (IAP), but use of functional Magnetic Resonance Imaging (fMRI) scanning is becoming more common. Few studies examine the correspondence between fMRI and IAP in pediatric samples. The current study examined the agreement of hemispheric lateralization as determined by fMRI and IAP in a consecutive sample of 10 pediatric patients with epilepsy evaluated for epilepsy surgery. Data showed a strong correlation between IAP and fMRI lateralilty indices (r=.91) and 70% agreement in determination of hemispheric dominance, despite increased demonstration of bilateral or atypical language representation in this pediatric sample. Clinical implications and interpretation challenges are discussed.
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Affiliation(s)
- Jennifer I Koop
- Department of Neurology (Neuropsychology), Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Kevin Credille
- Medical College of Wisconsin, Milwaukee, WI, United States
| | - Yang Wang
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michelle Loman
- Department of Neurology (Neuropsychology), Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ahmad Marashly
- Division of Pediatric Neurology, University of Washington/Seattle Children's Hospital, Seattle, WA, United States
| | - Irene Kim
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Sean M Lew
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Mohit Maheshwari
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
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Phillips NL, Shatil AS, Go C, Robertson A, Widjaja E. Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy. AJNR Am J Neuroradiol 2021; 42:1299-1304. [PMID: 33832955 DOI: 10.3174/ajnr.a7110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 02/16/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Task-based fMRI is a noninvasive method of determining language dominance; however, not all children can complete language tasks due to age, cognitive/intellectual, or language barriers. Task-free approaches such as resting-state fMRI offer an alternative method. This study evaluated resting-state fMRI for predicting language laterality in children with drug-resistant epilepsy. MATERIALS AND METHODS A retrospective review of 43 children with drug-resistant epilepsy who had undergone resting-state fMRI and task-based fMRI during presurgical evaluation was conducted. Independent component analysis of resting-state fMRI was used to identify language networks by comparing the independent components with a language network template. Concordance rates in language laterality between resting-state fMRI and each of the 4 task-based fMRI language paradigms (auditory description decision, auditory category, verbal fluency, and silent word generation tasks) were calculated. RESULTS Concordance ranged from 0.64 (95% CI, 0.48-0.65) to 0.73 (95% CI, 0.58-0.87), depending on the language paradigm, with the highest concordance found for the auditory description decision task. Most (78%-83%) patients identified as left-lateralized on task-based fMRI were correctly classified as left-lateralized on resting-state fMRI. No patients classified as right-lateralized or bilateral on task-based fMRI were correctly classified by resting-state fMRI. CONCLUSIONS While resting-state fMRI correctly classified most patients who had typical (left) language dominance, its ability to correctly classify patients with atypical (right or bilateral) language dominance was poor. Further study is required before resting-state fMRI can be used clinically for language mapping in the context of epilepsy surgery evaluation in children with drug-resistant epilepsy.
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Affiliation(s)
- N L Phillips
- From the Neurosciences and Mental Health Program (N.L.P., A.S.S., A.R., E.W.), The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Department of Psychology (N.L.P.)
| | - A S Shatil
- From the Neurosciences and Mental Health Program (N.L.P., A.S.S., A.R., E.W.), The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - C Go
- Division of Neurology (C.G., E.W.)
| | - A Robertson
- From the Neurosciences and Mental Health Program (N.L.P., A.S.S., A.R., E.W.), The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - E Widjaja
- From the Neurosciences and Mental Health Program (N.L.P., A.S.S., A.R., E.W.), The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Division of Neurology (C.G., E.W.)
- Department of Diagnostic Imaging (E.W.), The Hospital for Sick Children, Toronto, Ontario, Canada
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Redefining the role of Magnetoencephalography in refractory epilepsy. Seizure 2020; 83:70-75. [PMID: 33096459 DOI: 10.1016/j.seizure.2020.10.010] [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: 09/30/2020] [Accepted: 10/10/2020] [Indexed: 11/23/2022] Open
Abstract
Magnetoencephalography (MEG) possesses a number of features, including excellent spatiotemporal resolution, that lend itself to the functional imaging of epileptic activity. However its current use is restricted to specific scenarios, namely in the diagnosis refractory focal epilepsies where electroencephalography (EEG) has been inconclusive. This review highlights the recent progress of MEG within epilepsy, including advances in the technique itself such as simultaneous EEG/MEG and intracranial EEG/MEG recording and room temperature MEG recording using optically pumped magnetometers, as well as improved post processing of the data during interictal and ictal activity for accurate source localisation of the epileptogenic focus. These advances should broaden the scope of MEG as an important part of epilepsy diagnostics in the future.
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Patterns and predictors of language representation and the influence of epilepsy surgery on language reorganization in children and young adults with focal lesional epilepsy. PLoS One 2020; 15:e0238389. [PMID: 32898166 PMCID: PMC7478845 DOI: 10.1371/journal.pone.0238389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 08/14/2020] [Indexed: 11/19/2022] Open
Abstract
Mapping brain functions is crucial for neurosurgical planning in patients with drug-resistant seizures. However, presurgical language mapping using either functional or structural networks can be challenging, especially in children. In fact, most of the evidence on this topic derives from cross-sectional or retrospective studies in adults submitted to anterior temporal lobectomy. In this prospective study, we used fMRI and DTI to explore patterns of language representation, their predictors and impact on cognitive performances in 29 children and young adults (mean age at surgery: 14.6 ± 4.5 years) with focal lesional epilepsy. In 20 of them, we also assessed the influence of epilepsy surgery on language lateralization. All patients were consecutively enrolled at a single epilepsy surgery center between 2009 and 2015 and assessed with preoperative structural and functional 3T brain MRI during three language tasks: Word Generation (WG), Rhyme Generation (RG) and a comprehension task. We also acquired DTI data on arcuate fasciculus in 24 patients. We first assessed patterns of language representation (relationship of activations with the epileptogenic lesion and Laterality Index (LI)) and then hypothesized a causal model to test whether selected clinical variables would influence the patterns of language representation and the ensuing impact of the latter on cognitive performances. Twenty out of 29 patients also underwent postoperative language fMRI. We analyzed possible changes of fMRI and DTI LIs and their clinical predictors. Preoperatively, we found atypical language lateralization in four patients during WG task, in one patient during RG task and in seven patients during the comprehension task. Diffuse interictal EEG abnormalities predicted a more atypical language representation on fMRI (p = 0.012), which in turn correlated with lower attention (p = 0.036) and IQ/GDQ scores (p = 0.014). Postoperative language reorganization implied shifting towards atypical language representation. Abnormal postoperative EEG (p = 0.003) and surgical failures (p = 0.015) were associated with more atypical language lateralization, in turn correlating with worsened fluency. Neither preoperative asymmetry nor postoperative DTI LI changes in the arcuate fasciculus were observed. Focal lesional epilepsy associated with diffuse EEG abnormalities may favor atypical language lateralization and worse cognitive performances, which are potentially reversible after successful surgery.
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10
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Jacobs J. Networks in Posterior Cortex Epilepsies. Neurosurg Clin N Am 2020; 31:325-334. [PMID: 32475483 DOI: 10.1016/j.nec.2020.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Posterior cortex epilepsies comprise all epilepsies with seizures generated from the occipital, parietal, and posterior temporal areas. Seizures usually occur early in life. Visual phenomena during seizures are the hallmark for occipital lobe seizures. Most patients show objective semiology mimicking seizures from other brain regions. Separation of symptomatogenic and epileptogenic zones complicates diagnosis. Understanding networks of propagation is crucial for planning surgery. An overview about typical clinical findings and prognostic value is presented. It explains ways to investigate the epileptogenic zone and propagation pathways to identify seizures from the posterior cortex and better categorize epilepsies for precise surgical treatment.
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Affiliation(s)
- Julia Jacobs
- Alberta Children's Hospital, 28 Oki Drive Northwest, Calgary, Alberta T3B 6A8, Canada; Department of Pediatric Neurology and Muscular Disease, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany; Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.
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Pearce K, Dixon L, D'Arco F, Pujar S, Das K, Tahir Z, Tisdall M, Mankad K. Epilepsy surgery in children: what the radiologist needs to know. Neuroradiology 2020; 62:1061-1078. [PMID: 32435887 DOI: 10.1007/s00234-020-02448-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/27/2020] [Indexed: 12/18/2022]
Abstract
This review updates the radiologist on current epilepsy surgery practice in children, with a specific focus on the role of imaging in pre-surgical work-up, current and novel surgical techniques, expected post-surgical imaging appearances and important post-operative complications. A comprehensive review of the current and emerging international practices in paediatric epilepsy surgical planning and post-operative imaging is provided with details on case-based radiological findings. A detailed discussion of the pathophysiology and imaging features of different epileptogenic lesions will not be discussed as this is not the objective of this paper. Epilepsy surgery can be an effective method to control seizures in certain children with drug-resistant focal epilepsy. Early surgery in selected appropriate cases can lead to improved cognitive and developmental outcome. Advances in neurosurgical techniques, imaging and neuroanaesthesia have driven a parallel expansion in the array of epilepsy conditions which are potentially treatable with surgery. The range of surgical options is now wide, including minimally invasive ablative procedures for small lesions such as hypothalamic hamartomata, resections for focal lesions like hippocampal sclerosis and complex disconnective surgeries for multilobar conditions like Sturge Weber Syndrome and diffuse cortical malformations. An awareness of the surgical thinking when planning epilepsy surgery in children, and the practical knowledge of the operative steps involved will promote more accurate radiology reporting of the post-operative scan.
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Affiliation(s)
- Kirsten Pearce
- Department of Radiology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Luke Dixon
- Department of Radiology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Felice D'Arco
- Department of Radiology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Suresh Pujar
- Department of Neurology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Krishna Das
- Department of Neurology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Zubair Tahir
- Department of Neurosurgery, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Martin Tisdall
- Department of Neurosurgery, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK
| | - Kshitij Mankad
- Department of Radiology, Great Ormond Street Hospital NHS Foundation Trust, Great Ormond St, London, WC1N 3JH, UK.
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Guerin JB, Greiner HM, Mangano FT, Leach JL. Functional MRI in Children: Current Clinical Applications. Semin Pediatr Neurol 2020; 33:100800. [PMID: 32331615 DOI: 10.1016/j.spen.2020.100800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Functional magnetic resonance imaging has become a critical research tool for evaluating brain function during active tasks and resting states. This has improved our understanding of developmental trajectories in children as well as the plasticity of neural networks in disease states. In the clinical setting, functional maps of eloquent cortex in patients with brain lesions and/or epilepsy provides crucial information for presurgical planning. Although children are inherently challenging to scan in this setting, preparing them appropriately and providing adequate resources can help achieve useful clinical data. This article will review the basic underlying physiologic aspects of functional magnetic resonance imaging, review clinically relevant research applications, describe known validation data compared to gold standard techniques and detail future directions of this technology.
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Affiliation(s)
- Julie B Guerin
- Department of Pediatric Radiology and Medical Imaging, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Radiology, Mayo Clinic, Rochester, MN
| | - Hansel M Greiner
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Francesco T Mangano
- Division of Pediatric Neurosurgery, University of Cincinnati College of Medicine Department of Neurosurgery, Cincinnati, OH
| | - James L Leach
- Department of Pediatric Radiology and Medical Imaging, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Radiology, Mayo Clinic, Rochester, MN.
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Hur YJ. Guideline for advanced neuroimaging in pediatric epilepsy. Clin Exp Pediatr 2020; 63:100-101. [PMID: 32164045 PMCID: PMC7073381 DOI: 10.3345/cep.2019.01403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/10/2020] [Indexed: 11/27/2022] Open
Affiliation(s)
- Yun Jung Hur
- Department of Pediatrics, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Pusan, Korea
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14
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Lee YJ. Advanced neuroimaging techniques for evaluating pediatric epilepsy. Clin Exp Pediatr 2020; 63:88-95. [PMID: 32024331 PMCID: PMC7073377 DOI: 10.3345/kjp.2019.00871] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 11/06/2019] [Indexed: 01/11/2023] Open
Abstract
Accurate localization of the seizure onset zone is important for better seizure outcomes and preventing deficits following epilepsy surgery. Recent advances in neuroimaging techniques have increased our understanding of the underlying etiology and improved our ability to noninvasively identify the seizure onset zone. Using epilepsy-specific magnetic resonance imaging (MRI) protocols, structural MRI allows better detection of the seizure onset zone, particularly when it is interpreted by experienced neuroradiologists. Ultra-high-field imaging and postprocessing analysis with automated machine learning algorithms can detect subtle structural abnormalities in MRI-negative patients. Tractography derived from diffusion tensor imaging can delineate white matter connections associated with epilepsy or eloquent function, thus, preventing deficits after epilepsy surgery. Arterial spin-labeling perfusion MRI, simultaneous electroencephalography (EEG)-functional MRI (fMRI), and magnetoencephalography (MEG) are noinvasive imaging modalities that can be used to localize the epileptogenic foci and assist in planning epilepsy surgery with positron emission tomography, ictal single-photon emission computed tomography, and intracranial EEG monitoring. MEG and fMRI can localize and lateralize the area of the cortex that is essential for language, motor, and memory function and identify its relationship with planned surgical resection sites to reduce the risk of neurological impairments. These advanced structural and functional imaging modalities can be combined with postprocessing methods to better understand the epileptic network and obtain valuable clinical information for predicting long-term outcomes in pediatric epilepsy.
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Affiliation(s)
- Yun Jeong Lee
- Department of Pediatrics, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
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Meinhold T, Hofer W, Pieper T, Kudernatsch M, Staudt M. Presurgical Language fMRI in Children, Adolescents and Young Adults : A Validation Study. Clin Neuroradiol 2020; 30:691-704. [PMID: 31960077 DOI: 10.1007/s00062-019-00852-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/27/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE To validate four established, child-friendly functional magnetic resonance imaging (fMRI) language tasks (word chain task [WCT], vowel identification task [VIT], synonym task [SYT] and beep story task [BST]) in a predominantly pediatric cohort. METHODS Intracarotid amobarbital procedures (IAP) (n = 17) and unchanged language after hemispherotomy (n = 6) were used as gold standards. The fMRI activations of nine regions of interest (ROI) in the frontal, temporal and parietal lobes as well as in the cerebellum were visually assessed in 23 fMRI examinations (in total 117 fMRI task sessions) of 23 patients (age range 10.0-23.0 years) with drug-refractory epilepsies. RESULTS The ROIs were considered valid when they showed activation in more than 25% of all sessions for the respective task and never showed false lateralization (in comparison to gold standards). Thus, 13 valid, task-specific ROIs were identified: 5 ROIs for the WCT (frontal operculum, inferior frontal gyrus, middle frontal gyrus, intraparietal sulcus, cerebellum), 3 ROIs for the VIT (frontal operculum, inferior frontal gyrus, middle frontal gyrus), 3 ROIs for the SYT (frontal operculum, inferior frontal gyrus, temporal language area) and 2 ROIs for the BST (inferior frontal gyrus, middle frontal gyrus). CONCLUSION Clinical fMRI using the battery of four tasks is a valid tool for lateralizing language in children, adolescents and young adults. Each task proved to be specifically useful, which confirms that applying different tasks increases the probability of diagnosing language dominance in presurgical candidates.
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Affiliation(s)
- Theresa Meinhold
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schön Clinic Vogtareuth, Krankenhausstraße 20, 83569, Vogtareuth, Germany. .,Department of Pediatric Neurology and Developmental Medicine, Children's Hospital, University of Tübingen, Tübingen, Germany.
| | - Wiebke Hofer
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schön Clinic Vogtareuth, Krankenhausstraße 20, 83569, Vogtareuth, Germany
| | - Tom Pieper
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schön Clinic Vogtareuth, Krankenhausstraße 20, 83569, Vogtareuth, Germany
| | - Manfred Kudernatsch
- Center for Neurosurgery and Epilepsy Surgery, Schön Klinik Vogtareuth, Vogtareuth, Germany.,Research Institute "Rehabilitation, Transition, Palliation", PMU Salzburg, Salzburg, Austria
| | - Martin Staudt
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schön Clinic Vogtareuth, Krankenhausstraße 20, 83569, Vogtareuth, Germany.,Department of Pediatric Neurology and Developmental Medicine, Children's Hospital, University of Tübingen, Tübingen, Germany
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Ahsan SA, Chendeb K, Briggs RG, Fletcher LR, Jones RG, Chakraborty AR, Nix CE, Jacobs CC, Lack AM, Griffin DT, Teo C, Sughrue ME. Beyond eloquence and onto centrality: a new paradigm in planning supratentorial neurosurgery. J Neurooncol 2020; 146:229-238. [PMID: 31894519 DOI: 10.1007/s11060-019-03327-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 10/31/2019] [Indexed: 01/20/2023]
Abstract
PURPOSE Minimizing post-operational neurological deficits as a result of brain surgery has been one of the most pertinent endeavours of neurosurgical research. Studies have utilised fMRIs, EEGs and MEGs in order to delineate and establish eloquent areas, however, these methods have not been utilized by the wider neurosurgical community due to a lack of clinical endpoints. We sought to ascertain if there is a correlation between graph theory metrics and the neurosurgical notion of eloquent brain regions. We also wanted to establish which graph theory based nodal centrality measure performs the best in predicting eloquent areas. METHODS We obtained diffusion neuroimaging data from the Human Connectome Project (HCP) and applied a parcellation scheme to it. This enabled us to construct a weighted adjacency matrix which we then analysed. Our analysis looked at the correlation between PageRank centrality and eloquent areas. We then compared PageRank centrality to eigenvector centrality and degree centrality to see what the best measure of empirical neurosurgical eloquence was. RESULTS Areas that are considered neurosurgically eloquent tended to be predicted by high PageRank centrality. By using summary scores for the three nodal centrality measures we found that PageRank centrality best correlated to empirical neurosurgical eloquence. CONCLUSION The notion of eloquent areas is important to neurosurgery and graph theory provides a mathematical framework to predict these areas. PageRank centrality is able to consistently find areas that we consider eloquent. It is able to do so better than eigenvector and degree central measures.
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Affiliation(s)
- Syed Ali Ahsan
- Center for Minimally Invasive Neurosurgery, Prince of Wales Private Hospital, Suite 3, Level 7, Barker Street, Randwick, Sydney, NSW, 2031, Australia
| | - Kassem Chendeb
- Center for Minimally Invasive Neurosurgery, Prince of Wales Private Hospital, Suite 3, Level 7, Barker Street, Randwick, Sydney, NSW, 2031, Australia
| | - Robert G Briggs
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Luke R Fletcher
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Ryan G Jones
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Arpan R Chakraborty
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Cameron E Nix
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Christina C Jacobs
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Alison M Lack
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Daniel T Griffin
- Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Charles Teo
- Center for Minimally Invasive Neurosurgery, Prince of Wales Private Hospital, Suite 3, Level 7, Barker Street, Randwick, Sydney, NSW, 2031, Australia
| | - Michael Edward Sughrue
- Center for Minimally Invasive Neurosurgery, Prince of Wales Private Hospital, Suite 3, Level 7, Barker Street, Randwick, Sydney, NSW, 2031, Australia.
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Mapping critical hubs of receptive and expressive language using MEG: A comparison against fMRI. Neuroimage 2019; 201:116029. [PMID: 31325641 DOI: 10.1016/j.neuroimage.2019.116029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 07/08/2019] [Accepted: 07/16/2019] [Indexed: 01/22/2023] Open
Abstract
The complexity of the widespread language network makes it challenging for accurate localization and lateralization. Using large-scale connectivity and graph-theoretical analyses of task-based magnetoencephalography (MEG), we aimed to provide robust representations of receptive and expressive language processes, comparable with spatial profiles of corresponding functional magnetic resonance imaging (fMRI). We examined MEG and fMRI data from 12 healthy young adults (age 20-37 years) completing covert auditory word-recognition task (WRT) and covert auditory verb-generation task (VGT). For MEG language mapping, broadband (3-30 Hz) beamformer sources were estimated, voxel-level connectivity was quantified using phase locking value, and highly connected hubs were characterized using eigenvector centrality graph measure. fMRI data were analyzed using a classic general linear model approach. A laterality index (LI) was computed for 20 language-specific frontotemporal regions for both MEG and fMRI. MEG network analysis showed bilateral and symmetrically distributed hubs within the left and right superior temporal gyrus (STG) during WRT and predominant hubs in left inferior prefrontal gyrus (IFG) during VGT. MEG and fMRI localization maps showed high correlation values within frontotemporal regions during WRT and VGT (r = 0.63, 0.74, q < 0.05, respectively). Despite good concordance in localization, notable discordances were observed in lateralization between MEG and fMRI. During WRT, MEG favored a left-hemispheric dominance of left STG (LI = 0.25 ± 0.22) whereas fMRI supported a bilateral representation of STG (LI = 0.08 ± 0.2). Laterality of MEG and fMRI during VGT consistently showed a strong asymmetry in left IFG regions (MEG-LI = 0.45 ± 0.35 and fMRI-LI = 0.46 ± 0.13). Our results demonstrate the utility of a large-scale connectivity and graph theoretical analyses for robust identification of language-specific regions. MEG hubs are in great agreement with the literature in revealing with canonical and extra-canonical language sites, thus providing additional support for the underlying topological organization of receptive and expressive language cortices. Discordances in lateralization may emphasize the need for multimodal integration of MEG and fMRI to obtain an excellent predictive value in a heterogeneous healthy population and patients with neurosurgical conditions.
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An S, Bartolomei F, Guye M, Jirsa V. Optimization of surgical intervention outside the epileptogenic zone in the Virtual Epileptic Patient (VEP). PLoS Comput Biol 2019; 15:e1007051. [PMID: 31242177 PMCID: PMC6594587 DOI: 10.1371/journal.pcbi.1007051] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 04/17/2019] [Indexed: 01/18/2023] Open
Abstract
Studies to improve the efficacy of epilepsy surgery have focused on better refining the localization of the epileptogenic zone (EZ) with the aim of effectively resecting it. However, in a considerable number of patients, EZs are distributed across multiple brain regions and may involve eloquent areas that cannot be removed due to the risk of neurological complications. There is a clear need for developing alternative approaches to induce seizure relief, but minimal impact on normal brain functions. Here, we develop a personalized in-silico network approach, that suggests effective and safe surgical interventions for each patient. Based on the clinically identified EZ, we employ modularity analysis to identify target brain regions and fiber tracts involved in seizure propagation. We then construct and simulate a patient-specific brain network model comprising phenomenological neural mass models at the nodes, and patient-specific structural brain connectivity using the neuroinformatics platform The Virtual Brain (TVB), in order to evaluate effectiveness and safety of the target zones (TZs). In particular, we assess safety via electrical stimulation for pre- and post-surgical condition to quantify the impact on the signal transmission properties of the network. We demonstrate the existence of a large repertoire of efficient surgical interventions resulting in reduction of degree of seizure spread, but only a small subset of them proves safe. The identification of novel surgical interventions through modularity analysis and brain network simulations may provide exciting solutions to the treatment of inoperable epilepsies. We propose a personalized in-silico surgical approach able to suggest effective and safe surgical options for each epilepsy patient. In particular, we focus on deriving effective alternative methods for those cases where EZs are inoperable because of issues related with neurological complications. Based on modularity analysis using structural brain connectivity from each patient, TZs that would be considered as surgical sites are obtained. The acquired TZs are evaluated by personalized brain network simulations in terms of effectiveness and safety. Through the feedback approach combining modularity analysis and brain network simulations, the optimized TZ options that minimize seizure propagation while not affecting normal brain functions are obtained. Our study has a great importance in that it demonstrates the possibility of computational neuroscience field being able to construct a paradigm for personalized medicine by deriving innovative surgical options suitable for each patient and predicting the surgical outcomes.
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Affiliation(s)
- Sora An
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | | | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France
| | - Viktor Jirsa
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
- * E-mail:
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Juhász C, John F. Utility of MRI, PET, and ictal SPECT in presurgical evaluation of non-lesional pediatric epilepsy. Seizure 2019; 77:15-28. [PMID: 31122814 DOI: 10.1016/j.seizure.2019.05.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/12/2019] [Accepted: 05/10/2019] [Indexed: 12/12/2022] Open
Abstract
Children with epilepsy and normal structural MRI pose a particular challenge in localization of epileptic foci for surgical resection. Many of these patients have subtle structural lesions such as mild cortical dysplasia that can be missed by conventional MRI but may become detectable by optimized and advanced MRI acquisitions and post-processing. Specificity of objective analytic techniques such as voxel-based morphometry remains an issue. Combination of MRI with functional imaging approaches can improve the accuracy of detecting epileptogenic brain regions. Analysis of glucose positron emission tomography (PET) combined with high-resolution MRI can optimize detection of hypometabolic cortex associated with subtle cortical malformations and can also enhance presurgical evaluation in children with epileptic spasms. Additional PET tracers may detect subtle epileptogenic lesions and cortex with enhanced specificity in carefully selected subgroups with various etiologies; e.g., increased tryptophan uptake can identify epileptogenic cortical dysplasia in the interictal state. Subtraction ictal SPECT can be also useful to delineate ictal foci in those with non-localizing PET or after failed surgical resection. Presurgical delineation of language and motor cortex and the corresponding white matter tracts is increasingly reliable by functional MRI and DTI techniques; with careful preparation, these can be useful even in young and sedated children. While evidence-based pediatric guidelines are still lacking, the data accumulated in the last decade strongly indicate that multimodal imaging with combined analysis of MRI, PET, and/or ictal SPECT data can optimize the detection of subtle epileptogenic lesions and facilitate seizure-free outcome while minimizing the postsurgical functional deficit in children with normal conventional MRI.
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Affiliation(s)
- Csaba Juhász
- Department of Pediatrics, Wayne State University, PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien St., Detroit, Michigan, 48201, USA; Departments of Neurology and Neurosurgery, Wayne State University, 4201 St. Antoine St., Detroit, Michigan, 48201, USA.
| | - Flóra John
- Department of Pediatrics, Wayne State University, PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien St., Detroit, Michigan, 48201, USA; Department of Neurology, University of Pécs, H-7623, Rét u. 2., Pécs, Hungary.
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Presurgical electromagnetic functional brain mapping in refractory focal epilepsy. ZEITSCHRIFT FUR EPILEPTOLOGIE 2018. [DOI: 10.1007/s10309-018-0189-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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