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The role of SISCOM in preoperative evaluation for patients with epilepsy surgery: A meta-analysis. Seizure 2016; 41:43-50. [PMID: 27458682 DOI: 10.1016/j.seizure.2016.06.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To assess the specific value of subtraction ictal and inter-ictal SPECT co-registered to MRI (SISCOM) in identifying the epileptogenic zone (EZ) and predicting postoperative outcomes in epileptic surgical patients. METHOD A meta-analysis of studies published from January 1995 to June 2015 was conducted through a comprehensive literature search, and 11 studies were included. R software was first used to calculate a pooled positive rate, concordant rate and positive predictive value (PPV) for good outcomes. Stata software was then used to explore the relationship between SISCOM localization and surgical outcomes, including a subgroup analysis for extra-temporal lobe epilepsy. RESULTS The unweighted positive and concordant rates of SISCOM were 85.9% and 65.3%, respectively. In 142 MRI-negative patients, the SISCOM positive rate was 83.8%. The pooled PPV of 178 surgical patients with concordant SISCOM was 56%. In the meta-analysis of 275 surgical patients, the seizure-free odds ratio was 3.28-times higher in concordant than in non-concordant SISCOM patients [95%CI (1.90, 5.67)]. For extra-temporal lobe epilepsy, the seizure-free odds ratio was 2.44-times higher in concordant than in non-concordant SISCOM patients [95%CI (1.34, 4.43)]. CONCLUSION Our data indicate that SISCOM has moderate sensitivity in localizing the epileptogenic zone and can provide complementary information when MRI is negative. Furthermore, SISCOM localization concordant with the gold standard demonstrates slightly higher predictive value for good surgical outcomes. Further research is required to explore the influence of SISCOM localization results in temporal lobe versus extra-temporal lobe epilepsy.
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Davis MC, Broadwater DR, Mathews WH, Paige AL, DeWolfe JL, Elgavish RA, Riley KO, Ver Hoef LW. Statistical modeling of ICEEG features that determine resection planning. Clin Neurol Neurosurg 2016; 147:18-23. [PMID: 27249656 DOI: 10.1016/j.clineuro.2016.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 02/18/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
OBJECT The interpretation of intracranial EEG (ICEEG) recordings is a complex balance of the significance of specific rhythms and their relative timing to seizure onset. Ictal and interictal findings are evaluated in light of findings from cortical stimulation of eloquent cortex to determine the area of resection. PATIENTS AND METHODS Patients with ICEEG electrodes and subsequent surgical resection were retrospectively identified. Only the first 15s of ictal activity, which was divided into five 3-s epochs, was considered. Every electrode in each patient was considered a separate observation in a logistic regression model to predict whether the cortex under a given electrode was included in the planned resection. RESULTS 19 included patients had a total of 37 unique seizures. Recordings from a total of 1306 electrodes were analyzed. The strongest predictors of resection of cortex underlying a given electrode was the presence of low-voltage fast activity in Epoch 1, rhythmic spikes in Epoch 1, interictal paroxysmal fast activity, and low-voltage fast activity in Epoch 2. High-amplitude beta spikes and rhythmic slow waves were also significant predictors in Epoch 1. Interictal spikes had a higher odds ratio of affecting the planned resection if described as "continuous" or "very frequent". The presence of motor or language cortex were the strongest negative predictors of resecting underlying cortex. CONCLUSIONS Here we describe a novel model of ictal and interictal patterns significantly associated with the inclusion of cortex underlying a given ICEEG electrode in the surgical resection plan.
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Affiliation(s)
- Matthew C Davis
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Devin R Broadwater
- University of Alabama at Birmingham School of Medical, Birmingham, AL, United States.
| | - Winn H Mathews
- School of Medicine, University of South Alabama, Mobile, AL, United States
| | - A Lebron Paige
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jennifer L DeWolfe
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ro A Elgavish
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kristen O Riley
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lawrence W Ver Hoef
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
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Coan AC, Chaudhary UJ, Grouiller F, Campos BM, Perani S, De Ciantis A, Vulliemoz S, Diehl B, Beltramini GC, Carmichael DW, Thornton RC, Covolan RJ, Cendes F, Lemieux L. EEG-fMRI in the presurgical evaluation of temporal lobe epilepsy. J Neurol Neurosurg Psychiatry 2016. [PMID: 26216941 DOI: 10.1136/jnnp-2015-310401] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Drug-resistant temporal lobe epilepsy (TLE) often requires thorough investigation to define the epileptogenic zone for surgical treatment. We used simultaneous interictal scalp EEG-fMRI to evaluate its value for predicting long-term postsurgical outcome. METHODS 30 patients undergoing presurgical evaluation and proceeding to temporal lobe (TL) resection were studied. Interictal epileptiform discharges (IEDs) were identified on intra-MRI EEG and used to build a model of haemodynamic changes. In addition, topographic electroencephalographic correlation maps were calculated between the average IED during video-EEG and intra-MRI EEG, and used as a condition. This allowed the analysis of all data irrespective of the presence of IED on intra-MRI EEG. Mean follow-up after surgery was 46 months. International League Against Epilepsy (ILAE) outcomes 1 and 2 were considered good, and 3-6 poor, surgical outcome. Haemodynamic maps were classified according to the presence (Concordant) or absence (Discordant) of Blood Oxygen Level-Dependent (BOLD) change in the TL overlapping with the surgical resection. RESULTS The proportion of patients with good surgical outcome was significantly higher (13/16; 81%) in the Concordant than in the Discordant group (3/14; 21%) (χ(2) test, Yates correction, p=0.003) and multivariate analysis showed that Concordant BOLD maps were independently related to good surgical outcome (p=0.007). Sensitivity and specificity of EEG-fMRI results to identify patients with good surgical outcome were 81% and 79%, respectively, and positive and negative predictive values were 81% and 79%, respectively. INTERPRETATION The presence of significant BOLD changes in the area of resection on interictal EEG-fMRI in patients with TLE retrospectively confirmed the epileptogenic zone. Surgical resection including regions of haemodynamic changes in the TL may lead to better postoperative outcome.
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Affiliation(s)
- Ana C Coan
- Neuroimaging Laboratory, Department of Neurology, University of Campinas, Campinas, Brazil
| | - Umair J Chaudhary
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Frédéric Grouiller
- Department of Radiology and Medical Informatics, Geneva University Hospitals, Geneva, Switzerland
| | - Brunno M Campos
- Neuroimaging Laboratory, Department of Neurology, University of Campinas, Campinas, Brazil
| | - Suejen Perani
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Alessio De Ciantis
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Serge Vulliemoz
- EEG and Epilepsy Unit and Functional Brain Mapping Laboratory, Neurology Department, University Hospitals and Faculty of Medicine of University of Geneva, Geneva, Switzerland
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Guilherme C Beltramini
- Neurophysics Group, Gleb Wataghin Physics Institute, University of Campinas, Campinas, Brazil
| | - David W Carmichael
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Rachel C Thornton
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
| | - Roberto J Covolan
- Neurophysics Group, Gleb Wataghin Physics Institute, University of Campinas, Campinas, Brazil
| | - Fernando Cendes
- Neuroimaging Laboratory, Department of Neurology, University of Campinas, Campinas, Brazil
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, UK
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Sone D, Ota M, Yokoyama K, Sumida K, Kimura Y, Imabayashi E, Matsuda H, Sato N. Noninvasive evaluation of the correlation between regional cerebral blood flow and intraventricular brain temperature in temporal lobe epilepsy. Magn Reson Imaging 2016; 34:451-4. [DOI: 10.1016/j.mri.2015.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/14/2015] [Indexed: 11/16/2022]
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Pellegrino G, Hedrich T, Chowdhury R, Hall JA, Lina JM, Dubeau F, Kobayashi E, Grova C. Source localization of the seizure onset zone from ictal EEG/MEG data. Hum Brain Mapp 2016; 37:2528-46. [PMID: 27059157 DOI: 10.1002/hbm.23191] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION Surgical treatment of drug-resistant epilepsy relies on the identification of the seizure onset zone (SOZ) and often requires intracranial EEG (iEEG). We have developed a new approach for non-invasive magnetic and electric source imaging of the SOZ (MSI-SOZ and ESI-SOZ) from ictal magnetoencephalography (MEG) and EEG recordings, using wavelet-based Maximum Entropy on the Mean (wMEM) method. We compared the performance of MSI-SOZ and ESI-SOZ with interictal spike source localization (MSI-spikes and ESI-spikes) and clinical localization of the SOZ (i.e., based on iEEG or lesion topography, denoted as clinical-SOZ). METHODS A total of 46 MEG or EEG seizures from 13 patients were analyzed. wMEM was applied around seizure onset, centered on the frequency band showing the strongest power change. Principal component analysis applied to spatiotemporal reconstructed wMEM sources (0.4-1 s around seizure onset) identified the main spatial pattern of ictal oscillations. Qualitative sublobar concordance and quantitative measures of distance and spatial overlaps were estimated to compare MSI/ESI-SOZ with MSI/ESI-Spikes and clinical-SOZ. RESULTS MSI/ESI-SOZ were concordant with clinical-SOZ in 81% of seizures (MSI 90%, ESI 64%). MSI-SOZ was more accurate and identified sources closer to the clinical-SOZ (P = 0.012) and to MSI-Spikes (P = 0.040) as compared with ESI-SOZ. MSI/ESI-SOZ and MSI/ESI-Spikes did not differ in terms of concordance and distance from the clinical-SOZ. CONCLUSIONS wMEM allows non-invasive localization of the SOZ from ictal MEG and EEG. MSI-SOZ performs better than ESI-SOZ. MSI/ESI-SOZ can provide important additional information to MSI/ESI-Spikes during presurgical evaluation. Hum Brain Mapp 37:2528-2546, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Giovanni Pellegrino
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.,Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Tanguy Hedrich
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada
| | - Rasheda Chowdhury
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada
| | - Jeffery A Hall
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Jean-Marc Lina
- Département de Génie Electrique, École de Technologie Supérieure, Montreal, Québec, Canada.,Centre De Recherches En Mathématiques, Montreal, Québec, Canada.,Centre D'etudes Avancées En Médecine Du Sommeil, Centre De Recherche De L'hôpital Sacré-Coeur De Montréal, Montreal, Québec, Canada
| | - Francois Dubeau
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Eliane Kobayashi
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Christophe Grova
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.,Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.,Centre De Recherches En Mathématiques, Montreal, Québec, Canada.,Physics Department and PERFORM Centre, Concordia University, Montreal, Québec, Canada
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Pellegrino G, Machado A, von Ellenrieder N, Watanabe S, Hall JA, Lina JM, Kobayashi E, Grova C. Hemodynamic Response to Interictal Epileptiform Discharges Addressed by Personalized EEG-fNIRS Recordings. Front Neurosci 2016; 10:102. [PMID: 27047325 PMCID: PMC4801878 DOI: 10.3389/fnins.2016.00102] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/29/2016] [Indexed: 11/13/2022] Open
Abstract
Objective: We aimed at studying the hemodynamic response (HR) to Interictal Epileptic Discharges (IEDs) using patient-specific and prolonged simultaneous ElectroEncephaloGraphy (EEG) and functional Near InfraRed Spectroscopy (fNIRS) recordings. Methods: The epileptic generator was localized using Magnetoencephalography source imaging. fNIRS montage was tailored for each patient, using an algorithm to optimize the sensitivity to the epileptic generator. Optodes were glued using collodion to achieve prolonged acquisition with high quality signal. fNIRS data analysis was handled with no a priori constraint on HR time course, averaging fNIRS signals to similar IEDs. Cluster-permutation analysis was performed on 3D reconstructed fNIRS data to identify significant spatio-temporal HR clusters. Standard (GLM with fixed HRF) and cluster-permutation EEG-fMRI analyses were performed for comparison purposes. Results: fNIRS detected HR to IEDs for 8/9 patients. It mainly consisted oxy-hemoglobin increases (seven patients), followed by oxy-hemoglobin decreases (six patients). HR was lateralized in six patients and lasted from 8.5 to 30 s. Standard EEG-fMRI analysis detected an HR in 4/9 patients (4/9 without enough IEDs, 1/9 unreliable result). The cluster-permutation EEG-fMRI analysis restricted to the region investigated by fNIRS showed additional strong and non-canonical BOLD responses starting earlier than the IEDs and lasting up to 30 s. Conclusions: (i) EEG-fNIRS is suitable to detect the HR to IEDs and can outperform EEG-fMRI because of prolonged recordings and greater chance to detect IEDs; (ii) cluster-permutation analysis unveils additional HR features underestimated when imposing a canonical HR function (iii) the HR is often bilateral and lasts up to 30 s.
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Affiliation(s)
- Giovanni Pellegrino
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Alexis Machado
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Nicolas von Ellenrieder
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Satsuki Watanabe
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital Montreal, QC, Canada
| | - Jeffery A Hall
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital Montreal, QC, Canada
| | - Jean-Marc Lina
- Departement de Génie Electrique, Ecole de Technologie SupérieureMontreal, QC, Canada; Center of Advanced Research in Sleep Medicine, Hospital Du Sacre-CœurMontreal, QC, Canada; Centre de Recherches Mathematiques, University of MontréalMontreal, QC, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital Montreal, QC, Canada
| | - Christophe Grova
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, Montreal Neurological Institute, McGill UniversityMontreal, QC, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute and HospitalMontreal, QC, Canada; Centre de Recherches Mathematiques, University of MontréalMontreal, QC, Canada; Physics Department and Perform Center, Concordia UniversityMontreal, QC, Canada
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What is the concordance between the seizure onset zone and the irritative zone? A SEEG quantified study. Clin Neurophysiol 2016; 127:1157-1162. [DOI: 10.1016/j.clinph.2015.10.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 09/30/2015] [Accepted: 10/03/2015] [Indexed: 11/15/2022]
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58
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Song Y, Torres RA, Garcia S, Frometa Y, Bae J, Deshmukh A, Lin WC, Zheng Y, Riera JJ. Dysfunction of Neurovascular/Metabolic Coupling in Chronic Focal Epilepsy. IEEE Trans Biomed Eng 2016; 63:97-110. [DOI: 10.1109/tbme.2015.2461496] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Englot DJ, Raygor KP, Molinaro AM, Garcia PA, Knowlton RC, Auguste KI, Chang EF. Factors associated with failed focal neocortical epilepsy surgery. Neurosurgery 2015; 75:648-5;discussion 655; quiz 656. [PMID: 25181435 DOI: 10.1227/neu.0000000000000530] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Seizure outcomes after focal neocortical epilepsy (FNE) surgery are less favorable than after temporal lobectomy, and the reasons for surgical failure are incompletely understood. Few groups have performed an in-depth examination of seizure recurrences to identify possible reasons for failure. OBJECTIVE To elucidate factors contributing to FNE surgery failures. METHODS We reviewed resections for drug-resistant FNE performed at our institution between 1998 and 2011. We performed a quantitative analysis of seizure outcome predictors and a detailed qualitative review of failed surgical cases. RESULTS Of 138 resections in 125 FNE patients, 91 (66%) resulted in freedom from disabling seizures (Engel I outcome). Mean ± SEM patient age was 20.0 ± 1.2 years; mean follow-up was 3.8 years (range, 1-17 years); and 57% of patients were male. Less favorable (Engel II-IV) seizure outcome was predicted by higher preoperative seizure frequency (odds ratio = 0.85; 95% confidence interval, 0.78-0.93), a history of generalized tonic-clonic seizures (odds ratio = 0.42; 95% confidence interval, 0.18-0.97), and normal magnetic resonance imaging (odds ratio = 0.30; 95% confidence interval, 0.09-1.02). Among 36 surgical failures examined, 26 (72%) were related to extent of resection, with residual epileptic focus at the resection margins, whereas 10 (28%) involved location of resection, with an additional epileptogenic zone distant from the resection. Of 16 patients who received reoperation after seizure recurrence, 10 (63%) achieved seizure freedom. CONCLUSION Insufficient extent of resection is the most common reason for recurrent seizures after FNE surgery, although some patients harbor a remote epileptic focus. Many patients with incomplete seizure control are candidates for reoperation.
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Affiliation(s)
- Dario J Englot
- *Department of Neurological Surgery, ‡UCSF Comprehensive Epilepsy Center, and §Department of Neurology, University of California, San Francisco, California
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Patient-specific detection of cerebral blood flow alterations as assessed by arterial spin labeling in drug-resistant epileptic patients. PLoS One 2015; 10:e0123975. [PMID: 25946055 PMCID: PMC4422723 DOI: 10.1371/journal.pone.0123975] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/24/2015] [Indexed: 11/19/2022] Open
Abstract
Electrophysiological and hemodynamic data can be integrated to accurately and precisely identify the generators of abnormal electrical activity in drug-resistant focal epilepsy. Arterial Spin Labeling (ASL), a magnetic resonance imaging (MRI) technique for quantitative noninvasive measurement of cerebral blood flow (CBF), can provide a direct measure of variations in cerebral perfusion associated with the epileptic focus. In this study, we aimed to confirm the ASL diagnostic value in the identification of the epileptogenic zone, as compared to electrical source imaging (ESI) results, and to apply a template-based approach to depict statistically significant CBF alterations. Standard video-electroencephalography (EEG), high-density EEG, and ASL were performed to identify clinical seizure semiology and noninvasively localize the epileptic focus in 12 drug-resistant focal epilepsy patients. The same ASL protocol was applied to a control group of 17 healthy volunteers from which a normal perfusion template was constructed using a mixed-effect approach. CBF maps of each patient were then statistically compared to the reference template to identify perfusion alterations. Significant hypo- and hyperperfused areas were identified in all cases, showing good agreement between ASL and ESI results. Interictal hypoperfusion was observed at the site of the seizure in 10/12 patients and early postictal hyperperfusion in 2/12. The epileptic focus was correctly identified within the surgical resection margins in the 5 patients who underwent lobectomy, all of which had good postsurgical outcomes. The combined use of ESI and ASL can aid in the noninvasive evaluation of drug-resistant epileptic patients.
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All-in-one interictal presurgical imaging in patients with epilepsy: single-session EEG/PET/(f)MRI. Eur J Nucl Med Mol Imaging 2015; 42:1133-43. [PMID: 25893383 DOI: 10.1007/s00259-015-3045-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE In patients with pharmacoresistant focal epilepsy, resection of the epileptic focus can lead to freedom from seizures or significant improvement in well-selected candidates. Localization of the epileptic focus with multimodal concordance is crucial for a good postoperative outcome. Beyond the detection of epileptogenic lesions on structural MRI and focal hypometabolism on FDG PET, EEG-based Electric Source Imaging (ESI) and simultaneous EEG and functional MRI (EEG-fMRI) are increasingly applied for mapping epileptic activity. We here report presurgical multimodal interictal imaging using a hybrid PET/MR scanner for single-session FDG PET, MRI, EEG-fMRI and ESI. METHODS This quadrimodal imaging procedure was performed in a single session in 12 patients using a high-density (256 electrodes) MR-compatible EEG system and a hybrid PET/MR scanner. EEG was used to exclude subclinical seizures during uptake of the PET tracer, to compute ESI on interictal epileptiform discharges and to guide fMRI analysis for mapping haemodynamic changes correlated with interictal epileptiform activity. RESULTS The whole multimodal recording was performed in less than 2 hours with good patient comfort and data quality. Clinically contributory examinations with at least two modalities were obtained in nine patients and with all modalities in five patients. CONCLUSION This single-session quadrimodal imaging procedure provided reliable and contributory interictal clinical data. This procedure avoids multiple scanning sessions and is associated with less radiation exposure than PET-CT. Moreover, it guarantees the same medication level and medical condition for all modalities. The procedure improves workflow and could reduce the duration and cost of presurgical epilepsy evaluations.
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Pittau F, Mégevand P, Sheybani L, Abela E, Grouiller F, Spinelli L, Michel CM, Seeck M, Vulliemoz S. Mapping epileptic activity: sources or networks for the clinicians? Front Neurol 2014; 5:218. [PMID: 25414692 PMCID: PMC4220689 DOI: 10.3389/fneur.2014.00218] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/08/2014] [Indexed: 01/03/2023] Open
Abstract
Epileptic seizures of focal origin are classically considered to arise from a focal epileptogenic zone and then spread to other brain regions. This is a key concept for semiological electro-clinical correlations, localization of relevant structural lesions, and selection of patients for epilepsy surgery. Recent development in neuro-imaging and electro-physiology and combinations, thereof, have been validated as contributory tools for focus localization. In parallel, these techniques have revealed that widespread networks of brain regions, rather than a single epileptogenic region, are implicated in focal epileptic activity. Sophisticated multimodal imaging and analysis strategies of brain connectivity patterns have been developed to characterize the spatio-temporal relationships within these networks by combining the strength of both techniques to optimize spatial and temporal resolution with whole-brain coverage and directional connectivity. In this paper, we review the potential clinical contribution of these functional mapping techniques as well as invasive electrophysiology in human beings and animal models for characterizing network connectivity.
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Affiliation(s)
- Francesca Pittau
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Pierre Mégevand
- Laboratory for Multimodal Human Brain Mapping, Hofstra North Shore LIJ School of Medicine , Manhasset, NY , USA
| | - Laurent Sheybani
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Eugenio Abela
- Support Center of Advanced Neuroimaging (SCAN), Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital , Bern , Switzerland
| | - Frédéric Grouiller
- Radiology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Laurent Spinelli
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva , Geneva , Switzerland
| | - Margitta Seeck
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
| | - Serge Vulliemoz
- EEG and Epilepsy Unit, Neurology Department, University Hospitals and Faculty of Medicine of Geneva , Geneva , Switzerland
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