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Zhao K, Li Y, Lai H, Niu R, Li H, He S, Su Z, Gui Y, Ren L, Yang X, Zhou L. Alterations in HCN1 expression and distribution during epileptogenesis in rats. Epilepsy Res 2024; 202:107355. [PMID: 38555654 DOI: 10.1016/j.eplepsyres.2024.107355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/10/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and hippocampus. Under normal physiological conditions, HCN1 plays a crucial role in the excitatory and inhibitory regulation of neuronal networks. In temporal lobe epilepsy, the expression of HCN1 is decreased in the hippocampi of both animal models and patients. However, whether HCN1 expression changes during epileptogenesis preceding spontaneous seizures remains unclear. OBJECTIVE The aim of this study was to determine whether the expression of HCN1 is altered during the epileptic prodromal phase, thereby providing evidence for its role in epileptogenesis. METHODS We utilized a cobalt wire-induced rat epilepsy model to observe changes in HCN1 during epileptogenesis and epilepsy. Additionally, we also compared HCN1 alterations in epileptogenic tissues between cobalt wire- and pilocarpine-induced epilepsy rat models. Long-term video EEG recordings were used to confirm seizures development. Transcriptional changes, translation, and distribution of HCN1 were assessed using high-throughput transcriptome sequencing, total protein extraction, membrane and cytoplasmic protein fractionation, western blotting, immunohistochemistry, and immunofluorescence techniques. RESULTS In the cobalt wire-induced rat epilepsy model during the epileptogenesis phase, total HCN1 mRNA and protein levels were downregulated. Specifically, the membrane expression of HCN1 was decreased, whereas cytoplasmic HCN1 expression showed no significant change. The distribution of HCN1 in the distal dendrites of neurons decreased. During the epilepsy period, similar HCN1 alterations were observed in the neocortex of rats with cobalt wire-induced epilepsy and hippocampus of rats with lithium pilocarpine-induced epilepsy, including downregulation of mRNA levels, decreased total protein expression, decreased membrane expression, and decreased distal dendrite expression. CONCLUSIONS Alterations in HCN1 expression and distribution are involved in epileptogenesis beyond their association with seizure occurrence. Similarities in HCN1 alterations observed in epileptogenesis-related tissues from different models suggest a shared pathophysiological pathway in epileptogenesis involving HCN1 dysregulation. Therefore, the upregulation of HCN1 expression in neurons, maintenance of the HCN1 membrane, and distal dendrite distribution in neurons may represent promising disease-modifying strategies in epilepsy.
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Affiliation(s)
- Ke Zhao
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China; Guangzhou National Laboratory, Guangzhou, China; Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China
| | - Yinchao Li
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | | | - Ruili Niu
- Guangzhou National Laboratory, Guangzhou, China
| | - Huifeng Li
- Guangzhou National Laboratory, Guangzhou, China
| | - Shipei He
- Guangzhou National Laboratory, Guangzhou, China
| | - Zhengwei Su
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Yue Gui
- Guangzhou National Laboratory, Guangzhou, China
| | - Lijie Ren
- Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China.
| | | | - Liemin Zhou
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.
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Punyawai P, Usui N, Kondo A, Ichikawa N, Tottori T, Terada K, Takahashi Y, Inoue Y. Semiological differences of focal onset bilateral motor (convulsive) seizure between mesial temporal lobe epilepsy and neocortical epilepsy. Epilepsy Res 2021; 170:106553. [PMID: 33453690 DOI: 10.1016/j.eplepsyres.2021.106553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/01/2021] [Accepted: 01/05/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We investigated the semiology of focal onset bilateral motor (convulsive) seizure (FBMS) in patients with intractable focal epilepsy who underwent epilepsy surgery to understand its value in localizing the origin of the seizure. METHODS The study included 20 patients who underwent resective surgery after intracranial video-EEG monitoring (iEEG) with a favorable seizure outcome (Engel class I), and had at least one FBMS during iEEG. The diagnosis was mesial temporal lobe epilepsy (MTLE) for 7 patients and neocortical epilepsy (NE) for 13 patients (lateral temporal lobe, 3; posterior cortex, 6; frontal lobe, 3; perirolandic, 1). Videotaped FBMSs were carefully analyzed. RESULTS A generalized tonic phase appeared in all 7 patients with MTLE, but was absent in 6 of the 13 patients with NE (P = .044). Tonic cry was more frequently observed in MTLE than in NE (P = .012). Facial tonicity preceding limb tonicity was more frequently seen in patients with MTLE (P = .001). CONCLUSION Notably, patients with MTLE and those with NE showed semiological differences during bilateralization. FBMS includes not only focal to bilateral tonic-clonic seizure but also focal to bilateral clonic seizure.
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Affiliation(s)
- Pritsana Punyawai
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan; Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand
| | - Naotaka Usui
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan.
| | - Akihiko Kondo
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
| | - Naoki Ichikawa
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
| | - Takayasu Tottori
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
| | - Kiyohito Terada
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
| | - Yukitoshi Takahashi
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
| | - Yushi Inoue
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku, Shizuoka, Japan
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Nishimura M, Okanishi T, Fujimoto A, Kanai S, Sasaki Y, Homma Y, Otsubo H, Enoki H. Three phase-ictal scalp EEG patterns in patients with seizures arising from the cortex facing the interhemispheric fissure. Epilepsy Res 2018; 143:105-112. [PMID: 29475788 DOI: 10.1016/j.eplepsyres.2018.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/22/2018] [Accepted: 02/11/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Ictal scalp EEG patterns have been reported to vary across onset regions. We assessed the sequential EEG changes during seizure events on scalp EEG, and tested our hypothesis that patients with focal seizures arising from the cortex facing the interhemispheric fissure (IHF cortex) would be specifically characterized by 3 phase-EEG patterns (3Ph-EEG). METHODS Patient inclusion criteria were: 1) focal epilepsy and 2) ictal onset records on scalp and intracranial video-EEG. Patients were classified into one of the three groups: the IHF group, mesial temporal (MT) group, or lateral convexity (LC) group, based on the localization of the ictal onset zone (IOZ) on intracranial video-EEG. We defined 3Ph-EEG on ictal scalp EEG as follows: phase 1, brief spike/fast wave burst; phase 2, diffuse attenuation; and phase 3, focal rhythmic activity with evolution. We determined if the occurrence ratios of 3Ph-EEG and each of the three phases differed between the groups (IHF and others). RESULTS We studied 36 patients aged 8-59 years (mean, 30 years). Ten patients were classified as IHF, 16 as MT, and 10 as LC group from 303 ictal events on intracranial EEG. 193 seizures on scalp EEG consisted of 79 seizures in IHF; 58 in MT; 56 in LC group. Sixty-nine seizures (92%) in nine patients (90%) in IHF group showed 3Ph-EEG, whereas none of the seizures in MT and LC groups showed the 3Ph-EEG. Multivariate logistic regression analysis suggested that the presence of 3Ph-EEG (p < 0.01) and phase 2 (p = 0.03) components were predictive of IHF scalp EEG onset. SIGNIFICANCE The 3Ph-EEG may be observed preferentially in patients with focal seizures from IHF cortex. Observation of the ictal phases on scalp EEG may warrant consideration of intracranial EEG sampling for the presurgical evaluation.
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Affiliation(s)
- Mitsuyo Nishimura
- Department of Clinical Laboratory, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Tohru Okanishi
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan.
| | - Ayataka Fujimoto
- Epilepsy and Neurosurgery, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Sotaro Kanai
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Yuki Sasaki
- Department of Clinical Laboratory, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan; Department of Clinical Laboratory, St Luke's International Hospital, Akashi, Chuo-ku, Tokyo, 104-8560, Japan
| | - Yoichiro Homma
- Department of General Internal Medicine, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan
| | - Hiroshi Otsubo
- Department of Neurophysiology, Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Hideo Enoki
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, 430-8558, Japan
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Shirozu H, Hashizume A, Masuda H, Ito Y, Nakayama Y, Higashijima T, Fukuda M, Kameyama S. Analysis of ictal magnetoencephalography using gradient magnetic-field topography (GMFT) in patients with neocortical epilepsy. Clin Neurophysiol 2017. [PMID: 28646743 DOI: 10.1016/j.clinph.2017.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE We aimed to validate the usefulness of gradient magnetic-field topography (GMFT) for analysis of ictal magnetoencephalography (MEG) in patients with neocortical epilepsy. METHODS We identified 13 patients presenting with an ictal event during preoperative MEG. We applied equivalent current dipole (ECD) estimation and GMFT to detect and localize the ictal MEG onset, and compared these methods with the ictal onset zone (IOZ) derived from chronic intracranial electroencephalography. The surgical resection areas and outcomes were also evaluated. RESULTS GMFT detected and localized the ictal MEG onset in all patients, whereas ECD estimation showed localized ECDs in only 2. The delineation of GMFT was concordant with the IOZ at the gyral-unit level in 10 of 12 patients (83.3%). The detectability and precision of delineation of ictal MEG activity by GMFT were significantly superior to those of ECD (p<0.05 and p<0.01, respectively). Complete resection of the IOZ in the concordant group provided seizure freedom in 3 patients, whereas seizures remained in 9 patients who had incomplete resections. CONCLUSIONS Because of its higher spatial resolution, GMFT of ictal MEG is superior to conventional ECD estimation in patients with neocortical epilepsy. SIGNIFICANCE Ictal MEG study is a useful tool to estimate the seizure onset in patients with neocortical epilepsy.
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Affiliation(s)
- Hiroshi Shirozu
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan.
| | - Akira Hashizume
- Department of Neurosurgery, Takanobashi Central Hospital, 2-4-16, Kokutaiji-chou, Naka-ku, Hiroshima 730-0042, Japan
| | - Hiroshi Masuda
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Yosuke Ito
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Yoko Nakayama
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Takefumi Higashijima
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Masafumi Fukuda
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
| | - Shigeki Kameyama
- Department of Functional Neurosurgery, Nishi-Niigata Chuo National Hospital, 1-14-1, Masago, Nishi-ku, Niigata 950-2085, Japan
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Wang S, So NK, Jin B, Wang IZ, Bulacio JC, Enatsu R, Dai S, Chen Z, Gonzalez-Martinez J, Najm IM. Interictal ripples nested in epileptiform discharge help to identify the epileptogenic zone in neocortical epilepsy. Clin Neurophysiol 2017; 128:945-51. [PMID: 28412559 DOI: 10.1016/j.clinph.2017.03.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 02/20/2017] [Accepted: 03/15/2017] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study aimed to identify the subtype of interictal ripples that help delineate the epileptogenic zone in neocortical epilepsy. METHODS Totally 25 patients with focal neocortical epilepsy who had invasive electroencephalography (EEG) evaluation and subsequent surgery were included. They were followed up for at least 2years. Interictal ripples (80-250Hz) and fast ripples (250-500Hz) during slow-wave sleep were identified. Neocortical ripples were defined as type I ripples when they were superimposed on epileptiform discharges, and as type II ripples when they occurred independently. Resection ratio was calculated to present the extent to which the cortical area showing an interictal event or the seizure onset zone (SOZ) was completely removed. RESULTS Fast ripples and types I and II ripples were found in 8, 19, and 21 patients, respectively. Only the higher resection ratio of interictal fast or type I ripples was correlated to the Engel 1a surgical outcome. CONCLUSIONS Type I ripples could assist in localizing the epileptogenic zone in neocortical epilepsy. SIGNIFICANCE Type I and fast ripples both may be pathological high-frequency oscillations.
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Jehi L, Friedman D, Carlson C, Cascino G, Dewar S, Elger C, Engel J, Knowlton R, Kuzniecky R, McIntosh A, O'Brien TJ, Spencer D, Sperling MR, Worrell G, Bingaman B, Gonzalez-Martinez J, Doyle W, French J. The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia. Epilepsia 2015; 56:1526-33. [PMID: 26250432 DOI: 10.1111/epi.13116] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Epilepsy surgery is the most effective treatment for select patients with drug-resistant epilepsy. In this article, we aim to provide an accurate understanding of the current epidemiologic characteristics of this intervention, as this knowledge is critical for guiding educational, academic, and resource priorities. METHODS We profile the practice of epilepsy surgery between 1991 and 2011 in nine major epilepsy surgery centers in the United States, Germany, and Australia. Clinical, imaging, surgical, and histopathologic data were derived from the surgical databases at various centers. RESULTS Although five of the centers performed their highest number of surgeries for mesial temporal sclerosis (MTS) in 1991, and three had their highest number of MTS surgeries in 2001, only one center achieved its peak number of MTS surgeries in 2011. The most productive year for MTS surgeries varied then by center; overall, the nine centers surveyed performed 48% (95% confidence interval [CI] -27.3% to -67.4%) fewer such surgeries in 2011 compared to either 1991 or 2001, whichever was higher. There was a parallel increase in the performance of surgery for nonlesional epilepsy. Further analysis of 5/9 centers showed a yearly increase of 0.6 ± 0.07% in the performance of invasive electroencephalography (EEG) without subsequent resections. Overall, although MTS was the main surgical substrate in 1991 and 2001 (proportion of total surgeries in study centers ranging from 33.3% to 70.2%); it occupied only 33.6% of all resections in 2011 in the context of an overall stable total surgical volume. SIGNIFICANCE These findings highlight the major aspects of the evolution of epilepsy surgery across the past two decades in a sample of well-established epilepsy surgery centers, and the critical current challenges of this treatment option in addressing complex epilepsy cases requiring detailed evaluations. Possible causes and implications of these findings are discussed.
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Affiliation(s)
- Lara Jehi
- Department of Neurology, Cleveland Clinic, Cleveland, Ohio, U.S.A
| | - Daniel Friedman
- Department of Neurology, New York University, New York, New York, U.S.A
| | - Chad Carlson
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Gregory Cascino
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, U.S.A
| | - Sandra Dewar
- Department of Neurology, University of California-Los Angeles, Los Angeles, California, U.S.A
| | | | - Jerome Engel
- Department of Neurology, University of California-Los Angeles, Los Angeles, California, U.S.A
| | - Robert Knowlton
- Department of Neurology, University of California-San Francisco, San Francisco, California, U.S.A
| | - Ruben Kuzniecky
- Department of Neurology, New York University, New York, New York, U.S.A
| | - Anne McIntosh
- The Department of Medicine, The Royal Melbourne and Austin Hospitals, University of Melbourne, Melbourne, Victoria, Australia
| | - Terence J O'Brien
- The Department of Medicine, The Royal Melbourne and Austin Hospitals, University of Melbourne, Melbourne, Victoria, Australia
| | - Dennis Spencer
- Department of Neurology, Yale University, New Haven, Connecticut, U.S.A
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A
| | - Gregory Worrell
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, U.S.A
| | - Bill Bingaman
- Department of Neurology, Cleveland Clinic, Cleveland, Ohio, U.S.A
| | | | - Werner Doyle
- Department of Neurology, New York University, New York, New York, U.S.A
| | - Jacqueline French
- Department of Neurology, New York University, New York, New York, U.S.A
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Goncharova II, Spencer SS, Duckrow RB, Hirsch LJ, Spencer DD, Zaveri HP. Intracranially recorded interictal spikes: relation to seizure onset area and effect of medication and time of day. Clin Neurophysiol 2013; 124:2119-28. [PMID: 23856192 DOI: 10.1016/j.clinph.2013.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 04/01/2013] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The relationship between seizures and interictal spikes remains undetermined. We analyzed intracranial EEG (icEEG) recordings to examine the relationship between the seizure onset area and interictal spikes. METHODS 80 unselected patients were placed into 5 temporal, 4 extratemporal, and one unlocalized groups based on the location of the seizure onset area. We studied 4-h icEEG epochs, removed from seizures, from day-time and night-time during both on- and off-medication periods. Spikes were detected automatically from electrode contacts sampling the hemisphere ipsilateral to the seizure onset area. RESULTS There was a widespread occurrence of spikes over the hemisphere ipsilateral to the seizure onset area. The spatial distributions of spike rates for the different patient groups were different (p<0.0001, chi-square test). The area with the highest spike rate coincided with the seizure onset area only in half of the patients. CONCLUSION The spatial distribution of spike rates is strongly associated with the location of the seizure onset area, suggesting the presence of a distributed spike generation network, which is related to the seizure onset area. SIGNIFICANCE The spatial distribution of spike rates, but not the area with the highest spike rate, may hold value for the localization of the seizure onset area.
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Affiliation(s)
- Irina I Goncharova
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Chandra SP, Bal CS, Jain S, Joshua SP, Gaikwad S, Garg A, Ansari A, Nehra A, Sarkar C, Tripathi M. Intraoperative coregistration of magnetic resonance imaging, positron emission tomography, and electrocorticographic data for neocortical lesional epilepsies may improve the localization of the epileptogenic focus: a pilot study. World Neurosurg 2014; 82:110-7. [PMID: 23438971 DOI: 10.1016/j.wneu.2013.02.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Revised: 02/03/2013] [Accepted: 02/13/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To objectively mark out abnormal areas of magnetic resonance imaging (MRI), positron emission tomography (PET), and electrocorticography (ECoG) using neuronavigation so as to 1) enhance the accuracy of margins of the epileptogenic zone and 2) understand the relationships of all the three modalities with each other. METHODS A prospective study was conducted of 37 patients with intractable epilepsy due to lesional, neocortical pathologies from noneloquent areas. Prior to surgery, fusion and transfer of MRI and PET images onto a neuronavigation system was performed. At surgery, this was correlated to intraoperative ECoG using the electrode as referential points. An objective score was created for every electrode point that was correlated with MRI and PET abnormality at the point. The extent of surgical resection was mapped out using these data. RESULTS From a total of the data recorded from 1280 electrode points, 23.5% were located over the lesion. In addition, over the lesions, 93% of PET and 66% of ECoG points were abnormal. Over the perilesional areas, 43% of PET and 45% of ECoG points were abnormal. Using these data for surgery, both lesional and perileisonal areas were resected; 33/37 patients had good outcome (25 Engel I, 8 Engel II) (mean follow-up: 23.6 ± 3.2 months; range 18-31 months). CONCLUSION Multimodal imaging and ECoG using this method seems to provide a better objective localization of the epileptogenic foci.
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