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Puhlmann LMC, Linz R, Valk SL, Vrticka P, Vos de Wael R, Bernasconi A, Bernasconi N, Caldairou B, Papassotiriou I, Chrousos GP, Bernhardt BC, Singer T, Engert V. Association between hippocampal structure and serum Brain-Derived Neurotrophic Factor (BDNF) in healthy adults: A registered report. Neuroimage 2021; 236:118011. [PMID: 33852941 PMCID: PMC8280951 DOI: 10.1016/j.neuroimage.2021.118011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/20/2021] [Indexed: 01/09/2023] Open
Abstract
The hippocampus is a highly plastic brain structure supporting functions central to human cognition. Morphological changes in the hippocampus have been implicated in development, aging, as well as in a broad range of neurological and psychiatric disorders. A growing body of research suggests that hippocampal plasticity is closely linked to the actions of brain-derived neurotrophic factor (BDNF). However, evidence on the relationship between hippocampal volume (HCV) and peripheral BDNF levels is scarce and limited to elderly and patient populations. Further, despite evidence that BDNF expression differs throughout the hippocampus and is implicated in adult neurogenesis specifically in the dentate gyrus, no study has so far related peripheral BDNF levels to the volumes of individual hippocampal subfields. Besides its clinical implications, BDNF-facilitated hippocampal plasticity plays an important role in regulating cognitive and affective processes. In the current registered report, we investigated how serum BDNF (sBDNF) levels relate to volumes of the hippocampal formation and its subfields in a large sample of healthy adults (N = 279, 160 f) with a broad age range (20-55 years, mean 40.5) recruited in the context of the ReSource Project. We related HCV to basal sBDNF and, in a subsample (n = 103, 57 f), to acute stress-reactive change in sBDNF. We further tested the role of age as a moderator of both associations. Contrary to our hypotheses, neither basal sBDNF levels nor stress-reactive sBDNF change were associated with total HCV or volume of the dentate gyrus/cornu ammonis 4 (DG/CA4) subfield. We also found no evidence for a moderating effect of age on any of these associations. Our null results provide a first point of reference on the relationship between sBDNF and HCV in healthy mid-age, in contrast to patient or aging populations. We suggest that sBDNF levels have limited predictive value for morphological differences of the hippocampal structure when notable challenge to its neuronal integrity or to neurotrophic capacity is absent.
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Affiliation(s)
- L M C Puhlmann
- Research Group "Social Stress and Family Health", Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Leibniz Institute for Resilience Research, Mainz, Germany.
| | - R Linz
- Research Group "Social Stress and Family Health", Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - S L Valk
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; Institute of Neuroscience and Medicine (INM-7: Brain and Behaviour), Research Centre Jülich, Germany; Otto Hahn Research Group "Cognitive Neurogenetics", Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - P Vrticka
- Research Group "Social Stress and Family Health", Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Centre for Brain Science, Department of Psychology, University of Essex, Colchester, UK
| | - R Vos de Wael
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, H3A2B4, Montreal, Canada
| | - A Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, H3A2B4, Montreal, Canada
| | - N Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, H3A2B4, Montreal, Canada
| | - B Caldairou
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, H3A2B4, Montreal, Canada
| | - I Papassotiriou
- Department of Clinical Biochemistry, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - G P Chrousos
- First Department of Pediatrics, School of Medicine, National and Kapodistrian University of Athens, Greece
| | - B C Bernhardt
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, H3A2B4, Montreal, Canada
| | - T Singer
- Social Neuroscience Lab, Max Planck Society, Berlin, Germany
| | - V Engert
- Research Group "Social Stress and Family Health", Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Institute of Psychosocial Medicine, Psychotherapy and Psychooncology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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Tai XY, Bernhardt B, Thom M, Thompson P, Baxendale S, Koepp M, Bernasconi N. Review: Neurodegenerative processes in temporal lobe epilepsy with hippocampal sclerosis: Clinical, pathological and neuroimaging evidence. Neuropathol Appl Neurobiol 2018; 44:70-90. [DOI: 10.1111/nan.12458] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 12/07/2017] [Indexed: 12/14/2022]
Affiliation(s)
- X. Y. Tai
- Division of Neuropathology and Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - B. Bernhardt
- Neuroimaging of Epilepsy Laboratory; McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
- Multimodal Imaging and Connectome Analysis Lab; Montreal Neurological Institute; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
| | - M. Thom
- Division of Neuropathology and Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - P. Thompson
- Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - S. Baxendale
- Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - M. Koepp
- Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - N. Bernasconi
- Neuroimaging of Epilepsy Laboratory; McConnell Brain Imaging Centre; Montreal Neurological Institute; McGill University; Montreal Quebec Canada
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Abstract
OBJECTIVE Converging evidence suggests that abnormalities of brain development may play a role in the pathogenesis of temporal lobe epilepsy (TLE). As sulco-gyral patterns are thought to be a footprint of cortical development, we set out to quantitatively map folding complexity across the neocortex in TLE. Additionally, we tested whether there was a relationship between cortical complexity and features of hippocampal maldevelopment, commonly referred to as malrotation. METHODS To quantify folding complexity, we obtained whole-brain surface-based measures of absolute mean cortical curvature from MRI scans acquired in 43 drug-resistant patients with TLE with unilateral hippocampal atrophy, and 40 age- and sex-matched healthy controls. In patients, we correlated changes in cortical curvature with 3-dimensional measures of hippocampal positioning. RESULTS We found increased folding complexity in the temporolimbic cortices encompassing parahippocampal, temporopolar, insular, and fronto-opercular regions. Increased complexity was observed ipsilateral to the seizure focus in patients with left TLE (LTLE), whereas these changes were bilateral in patients with right TLE (RTLE). In both TLE groups, increased temporolimbic complexity was associated with increased hippocampal malrotation. We found tendencies for increased complexity in bilateral posterior temporal cortices in LTLE and contralateral parahippocampal cortices in RTLE to be predictive of unfavorable seizure outcome after surgery. CONCLUSION The anatomic distribution of increased cortical complexity overlapping with limbic seizure networks in TLE and its association with hippocampal maldevelopment further imply that neurodevelopmental factors may play a role in the epileptogenic process of TLE.
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Affiliation(s)
- N L Voets
- Department of Neurology and McConnell Brain Imaging Center, Montreal Neurological Institute (WB-322), 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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Bernhardt BC, Bernasconi N, Concha L, Bernasconi A. Cortical thickness analysis in temporal lobe epilepsy: Reproducibility and relation to outcome. Neurology 2010; 74:1776-84. [DOI: 10.1212/wnl.0b013e3181e0f80a] [Citation(s) in RCA: 171] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Bernhardt BC, Kim H, Natsume J, Bernasconi N, Bernasconi A. Temporal lobe epilepsy is associated with atrophy of limbic thalamic nuclei. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)71036-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Bernhardt BC, Worsley KJ, Kim H, Evans AC, Bernasconi A, Bernasconi N. Longitudinal and cross-sectional analysis of atrophy in pharmacoresistant temporal lobe epilepsy. Neurology 2009; 72:1747-54. [PMID: 19246420 DOI: 10.1212/01.wnl.0000345969.57574.f5] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Whether recurrent epileptic seizures induce brain damage is debated. Disease progression in epilepsy has been evaluated only in a few community-based studies involving patients with seizures well controlled by medication. These studies concluded that epilepsy does not inevitably lead to global cerebral damage. OBJECTIVE To track the progression of neocortical atrophy in pharmacoresistant temporal lobe epilepsy (TLE) using longitudinal and cross-sectional designs. METHODS Using a fully automated measure of cortical thickness on MRI, we studied a homogeneous sample of patients with pharmacoresistant TLE. In the longitudinal analysis (n = 18), fixed-effect models were used to quantify cortical atrophy over a mean interscan interval of 2.5 years (range = 7 to 90 months). In the cross-sectional analysis (n = 121), we correlated epilepsy duration and thickness. To dissociate normal aging from pathologic progression, we compared aging effects in TLE to healthy controls. RESULTS The longitudinal analysis mapped progression in ipsilateral temporopolar and central and contralateral orbitofrontal, insular, and angular regions. In patients with more than 14 years of disease, atrophy progressed more rapidly in frontocentral and parietal regions that in those with shorter duration. The cross-sectional study showed progressive atrophy in the mesial and superolateral frontal, and parietal cortices. CONCLUSIONS Our combined cross-sectional and longitudinal analysis in patients with pharmacoresistant temporal lobe epilepsy demonstrated progressive neocortical atrophy over a mean interval of 2.5 years that is distinct from normal aging, likely representing seizure-induced damage. The cumulative character of atrophy underlies the importance of early surgical treatment in this group of patients.
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Affiliation(s)
- B C Bernhardt
- Department of Neurology, Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
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Kim H, Bernasconi N, Bernhardt B, Colliot O, Bernasconi A. Basal temporal sulcal morphology in healthy controls and patients with temporal lobe epilepsy. Neurology 2008; 70:2159-65. [DOI: 10.1212/01.wnl.0000313150.62832.79] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Natsume J, Bernasconi N, Miyauchi M, Naiki M, Yokotsuka T, Sofue A, Bernasconi A. Hippocampal volumes and diffusion-weighted image findings in children with prolonged febrile seizures. Acta Neurol Scand 2007; 115:25-8. [PMID: 17362273 DOI: 10.1111/j.1600-0404.2007.00806.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To assess hippocampal volumes (HV) and signal changes on diffusion-weighted imaging (DWI) within 5 days of prolonged febrile seizures (PFS) and compare them with the PFS duration and EEG. METHODS We studied 12 children (mean age: 32 +/- 21 months, range 10 months-5 years) within 5 days of a first episode of PFS (a seizure or series of seizures lasting for 30 min or longer, without return of consciousness between the seizures). The HV measurements were carried out using high-resolution magnetic resonance imaging and signal intensity abnormalities were evaluated visually on DWI. HV in patients were compared with those of 13 neurologically normal controls (mean age 31 +/- 16 months, range 15 months-5 years). HV abnormalities correlated with PFS duration. HV and DWI abnormalities were compared with EEG abnormalities. RESULTS Seizure duration ranged from 40 to 95 min. In seven out of twelve patients, seizures were refractory and lasted for 60 min or longer despite intravenous infusion of diazepam. In the patients with PFS for 60 min or longer, HV were significantly larger than that of controls. In all patients, there was a positive correlation between HV and seizure duration. DWI showed hyperintensity in unilateral hippocampus in three patients with intractable seizures, ipsilateral thalamus in two, and cingulate in one. EEG showed abnormalities in temporal areas ipsilateral to the DWI abnormalities in these patients. CONCLUSIONS Large HV and hippocampal hyperintensity on DWI were seen in patients with refractory PFS. Our results suggest that medically refractory PFS lasting for 60 min or longer may cause structural changes in limbic structures that could promote later epileptogenesis.
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Affiliation(s)
- J Natsume
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
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Natsume J, Bernasconi N, Miyauchi M, Naiki M, Yokotsuka T, Sofue A, Bernasconi A. Hippocampal volumes and diffusion-weighted image findings in children with prolonged febrile seizures. Acta Neurol Scand Suppl 2007; 186:25-8. [PMID: 17784534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
OBJECTIVES To assess hippocampal volumes (HV) and signal changes on diffusion-weighted imaging (DWI) within 5 days of prolonged febrile seizures (PFS) and compare them with the PFS duration and EEG. METHODS We studied 12 children (mean age: 32 +/- 21 months, range 10 months-5 years) within 5 days of a first episode of PFS (a seizure or series of seizures lasting for 30 min or longer, without return of consciousness between the seizures). The HV measurements were carried out using high-resolution magnetic resonance imaging and signal intensity abnormalities were evaluated visually on DWI. HV in patients were compared with those of 13 neurologically normal controls (mean age 31 +/- 16 months, range 15 months-5 years). HV abnormalities correlated with PFS duration. HV and DWI abnormalities were compared with EEG abnormalities. RESULTS Seizure duration ranged from 40 to 95 min. In seven out of twelve patients, seizures were refractory and lasted for 60 min or longer despite intravenous infusion of diazepam. In the patients with PFS for 60 min or longer, HV were significantly larger than that of controls. In all patients, there was a positive correlation between HV and seizure duration. DWI showed hyperintensity in unilateral hippocampus in three patients with intractable seizures, ipsilateral thalamus in two, and cingulate in one. EEG showed abnormalities in temporal areas ipsilateral to the DWI abnormalities in these patients. CONCLUSIONS Large HV and hippocampal hyperintensity on DWI were seen in patients with refractory PFS. Our results suggest that medically refractory PFS lasting for 60 min or longer may cause structural changes in limbic structures that could promote later epileptogenesis.
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Affiliation(s)
- J Natsume
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
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Colliot O, Mansi T, Bernasconi N, Naessens V, Klironomos D, Bernasconi A. Segmentation of focal cortical dysplasia lesions on MRI using level set evolution. Neuroimage 2006; 32:1621-30. [PMID: 16887367 DOI: 10.1016/j.neuroimage.2006.04.225] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 04/14/2006] [Accepted: 04/28/2006] [Indexed: 11/15/2022] Open
Abstract
Focal cortical dysplasia (FCD) is the most frequent malformation of cortical development in patients with medically intractable epilepsy. On MRI, FCD lesions are not easily differentiable from the normal cortex and defining their spatial extent is challenging. In this paper, we introduce a method to segment FCD lesions on T1-weighted MRI. It relies on two successive three-dimensional deformable models, whose evolutions are based on the level set framework. The first deformable model is driven by probability maps obtained from three MRI features: cortical thickness, relative intensity and gradient. These features correspond to the visual characteristics of FCD and allow discriminating lesions and normal tissues. In a second stage, the previous result is expanded towards the underlying and overlying cortical boundaries, throughout the whole cortical section. The method was quantitatively evaluated by comparison with manually traced labels in 18 patients with FCD. The automated segmentations achieved a strong agreement with the manuals labels, demonstrating the applicability of the method to assist the delineation of FCD lesions on MRI. This new approach may become a useful tool for the presurgical evaluation of patients with intractable epilepsy related to cortical dysplasia.
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Affiliation(s)
- O Colliot
- Department of Neurology and Neurosurgery and McConnell Brain Imaging Center, Montreal Neurological Institute, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
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Colliot O, Mansi T, Bernasconi N, Naessens V, Klironomos D, Bernasconi A. Segmentation of focal cortical dysplasia lesions using a feature-based level set. ACTA ACUST UNITED AC 2006; 8:375-82. [PMID: 16685868 DOI: 10.1007/11566465_47] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Focal cortical dysplasia (FCD), a malformation of cortical development, is an important cause of medically intractable epilepsy. FCD lesions are difficult to distinguish from non-lesional cortex and their delineation on MRI is a challenging task. This paper presents a method to segment FCD lesions on T1-weighted MRI, based on a 3D deformable model, implemented using the level set framework. The deformable model is driven by three MRI features: cortical thickness, relative intensity and gradient. These features correspond to the visual characteristics of FCD and allow to differentiate lesions from normal tissues. The proposed method was tested on 18 patients with FCD and its performance was quantitatively evaluated by comparison with the manual tracings of two trained raters. The validation showed that the similarity between the level set segmentation and the manual labels is similar to the agreement between the two human raters. This new approach may become a useful tool for the presurgical evaluation of patients with intractable epilepsy.
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Affiliation(s)
- O Colliot
- Montreal Neurological Institute, McGill University, Montreal, Canada
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12
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Montenegro MA, Kinay D, Cendes F, Bernasconi A, Bernasconi N, Coan AC, Li LM, Guerreiro MM, Guerreiro CAM, Lopes-Cendes I, Andermann E, Dubeau F, Andermann F. Patterns of hippocampal abnormalities in malformations of cortical development. J Neurol Neurosurg Psychiatry 2006; 77:367-71. [PMID: 16484646 PMCID: PMC2077709 DOI: 10.1136/jnnp.2005.070417] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To assess whether different types of malformation of cortical development (MCD) are associated with specific patterns of hippocampal abnormalities. METHODS A total of 122 consecutive patients with MRI diagnosis of MCD (53 males, age range 1-58 years) were included in the study. Hippocampal measurements were made on 1-3 mm coronal T1-weighted MRIs and compared with MRIs of normal controls. RESULTS A total of 39 patients had focal cortical dysplasia, 5 had hemimegalencephaly, 5 had lissencephaly-agyria-pachygyria, 11 had SLH, 11 had PNH, 12 had bilateral contiguous PNH, 5 had schizencephaly, and 34 had polymicrogyria. The frequency of hippocampal abnormalities in these patients with MCD was 29.5%. A small hippocampus was present in all types of MCD. Only patients with lissencephaly and SLH had an enlarged hippocampus. Abnormalities in hippocampal rotation and shape were present in all types of MCD; however, these predominated in PNH. None of the patients with lissencephaly-agyria-pachygyria or SLH had hyperintense signal on T2 or FLAIR images or abnormal hippocampal internal architecture. CONCLUSION A small hippocampus was present in all types of MCD; however, the classic MRI characteristics of hippocampal sclerosis were often lacking. Abnormal enlargement of the hippocampus was associated with only diffuse MCD due to abnormal neuronal migration (lissencephaly-agyria-pachygyria and SLH).
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Affiliation(s)
- M A Montenegro
- Department of Neurology, University of Campinas/FCM-UNICAMP, Campinas, SP, Brazil
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Duchesne S, Bernasconi N, Bernasconi A, Collins DL. MR-based neurological disease classification methodology: Application to lateralization of seizure focus in temporal lobe epilepsy. Neuroimage 2006; 29:557-66. [PMID: 16168675 DOI: 10.1016/j.neuroimage.2005.07.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 07/15/2005] [Accepted: 07/20/2005] [Indexed: 11/20/2022] Open
Abstract
Classification approaches for neurological diseases tend to concentrate on specific structures such as the hippocampus (HC). The hypothesis for the novel methodology presented in this work is that pathologies will impact large tissue areas with detectable variations of T1-weighted MR signal intensity and registration metrics. The technique is applied to lateralization of seizure focus in 127 patients with intractable temporal lobe epilepsy (TLE), in which the site of seizure onset was determined by comprehensive evaluation (69 with left MTL seizure focus (SF) (group "L") and 58 with right SF (group "R")). The method analyses large, non-specific Volumes of Interest (VOI) centered on the left and right medial temporal lobes (MTL) (55 x 82 x 80 voxels) in pre-processed scans aligned in stereotaxic space. Extracted VOIs are linearly and nonlinearly registered to a reference target image. Principal Components Analyses of (i) the normalized intensity and (ii) the trace, a measure of local volume change, are used to generate a multidimensional reference space from a set of 152 neurologically healthy subjects. VOIs from TLE patients, processed in a similar fashion, are projected in this space, and leave-one-out, forward stepwise linear discriminant analysis of the eigencoordinate distributions is used for classification. Following manual MRI volumetric analysis, 80 patients had HC atrophy (group "HA") ipsilateral to the SF (42 with left SF or "LHA", and 38 with right or "RHA"), and the remaining 47 had normal HC volumes (group "HNV") (27 with left SF or "LNV", and 20 with right SF or "RNV"). The automated method was 100% accurate at separating "HA" vs. "HNV", "LHA" vs. "RHA", and "LNV" vs "RNV". It was also 96% accurate at separating "L" vs. "R". Our results indicate that MR data projected in multidimensional feature domains can lateralize SF in epilepsy patients with a high accuracy, irrespective of HC volumes. This single-scan, practical and objective method holds promise for the pre-surgical evaluation of TLE patients.
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Affiliation(s)
- S Duchesne
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, 3801, University St., Montréal, Canada H3A 2B4.
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Abstract
OBJECTIVE To report the assessment of a patient exhibiting gustatory agnosia. METHODS Preoperative and postoperative neuropsychological, neuroimaging, and chemosensory evaluations were performed in a 39-year-old woman undergoing surgical treatment for intractable epilepsy. RESULTS Preoperative MRIs showed bilateral (right > left) atrophy in the medial temporal lobes and complete atrophy of the left insula. Evaluation of gustatory function revealed normal suprathreshold intensity estimation, affective evaluation, and detection thresholds but elevated recognition thresholds. A functional neuroimaging study showed activation to stimulation of aversive taste in the left amygdala. Surgical treatment entailed resection from the left medial temporal lobe that included the region of amygdala that had responded to taste. Postoperatively, detection, naming, and intensity estimation for taste remained normal, but the patient was unable to recognize different tastes (sweet, sour, salty, and bitter). A second evaluation 2.5 years after her surgery revealed no change in taste ability. CONCLUSION The anteromedial temporal lobe has an important role in recognizing taste quality.
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Affiliation(s)
- D M Small
- The John B. Pierce Laboratory, Yale University School of Medicine, 290 Congress Avenue, New Haven, CT 06519, USA.
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Colliot O, Bernasconi N, Khalili N, Antel SB, Naessens V, Bernasconi A. Individual voxel-based analysis of gray matter in focal cortical dysplasia. Neuroimage 2005; 29:162-71. [PMID: 16099679 DOI: 10.1016/j.neuroimage.2005.07.021] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 06/29/2005] [Accepted: 07/05/2005] [Indexed: 10/25/2022] Open
Abstract
High-resolution MRI of the brain has made it possible to identify focal cortical dysplasia (FCD) in an increasing number of patients. There is evidence for structural abnormalities extending beyond the visually identified FCD lesion. Voxel-based morphometry (VBM) has the potential of detecting both lesions and extra-lesional abnormalities because it performs a whole brain voxel-wise comparison. However, on T1-weighted MRI, FCD lesions are characterized by a wide spectrum of signal hyperintensity that may compromise the results of the segmentation step in VBM. Our purpose was to investigate gray matter (GM) changes in individual FCD patients using voxel-based morphometry (VBM). In addition, we sought to assess the performance of this technique for FCD detection with respect to lesion intensity using an operator designed to emphasize areas of hyperintense T1 signal. We studied 27 patients with known FCD and focal epilepsy and 39 healthy controls. We compared the GM map of each subject (controls and patients) with the average GM map of all controls and obtained a GM z-score map for each individual. The protocol being designed to achieve a maximal specificity, no differences in GM concentration were found in the control group. The z-score maps showed an increase in GM that coincided with the lesion in 21/27 (78%) patients. Five of the six remaining patients whose lesions were not detected by VBM presented with a strong lesion hyperintensity, and a significant part of their lesion was misclassified as white matter. In 16/27 (59%) patients, there were additional areas of GM increase distant from the primary lesion. Areas of GM decrease were found in 8/27 (30%) patients. In conclusion, individual voxel-based analysis was able to detect FCD in a majority of patients. Moreover, FCD was often associated with widespread GM changes extending beyond the visible lesion. In its current form, however, individual VBM may be unable to detect lesions characterized by strong signal intensity abnormalities.
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Affiliation(s)
- O Colliot
- Department of Neurology and Neurosurgery and McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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Bernasconi N, Kinay D, Andermann F, Antel S, Bernasconi A. Analysis of shape and positioning of the hippocampal formation: an MRI study in patients with partial epilepsy and healthy controls. ACTA ACUST UNITED AC 2005; 128:2442-52. [PMID: 16014649 DOI: 10.1093/brain/awh599] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The purpose of this study was to evaluate systematically shape and positioning of the hippocampal formation (HF) in patients with partial epilepsy related to malformations of cortical development (MCD) and those with temporal lobe epilepsy (TLE). We studied 76 patients with MCD, including focal cortical dysplasia (n = 29; lesions located outside the temporal lobe in all), heterotopia (lesions outside of the temporal lobe, n = 14; lesions extending into the temporal lobe, n = 16), polymicrogyria (bilateral perisylvian, n = 14; unilateral perisylvian, n = 3) and 30 patients with TLE (hippocampal atrophy, n = 15; normal hippocampal volumes, n = 15). Shape and positioning of the HF were evaluated using a set of eight predefined morphological characteristics. In addition, the degree of hippocampal vertical orientation and medial positioning were assessed quantitatively. Patients were compared with 50 healthy controls. At least three criteria describing abnormal HF shape and positioning were found in 5/50 (10%) healthy controls, 37/76 (49%) MCD and 13/30 (43%) TLE patients. An association with all criteria was found in MCD and TLE, but not in healthy controls. In MCD there was no association between the side of HF shape abnormalities and the side of the cortical malformation or the EEG focus. Likewise, in TLE, HF abnormalities were not related to the side of the EEG focus. In both MCD and TLE patients who had hippocampal atrophy, no association was found between the side of HF shape abnormalities and the side of atrophy. Abnormal HF shape and positioning are found in a similar proportion in MCD and TLE. In TLE, they may be a marker of a more extensive disorder of brain development and may participate in the development of this condition.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
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Bernasconi N, Duchesne S, Janke A, Lerch J, Collins DL, Bernasconi A. Whole-brain voxel-based statistical analysis of gray matter and white matter in temporal lobe epilepsy. Neuroimage 2005; 23:717-23. [PMID: 15488421 DOI: 10.1016/j.neuroimage.2004.06.015] [Citation(s) in RCA: 227] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 06/05/2004] [Accepted: 06/14/2004] [Indexed: 12/31/2022] Open
Abstract
Volumetric MRI studies based on manual labeling of selected anatomical structures have provided in vivo evidence that brain abnormalities associated with temporal lobe epilepsy (TLE) extend beyond the hippocampus. Voxel-based morphometry (VBM) is a fully automated image analysis technique allowing identification of regional differences in gray matter (GM) and white matter (WM) between groups of subjects without a prior region of interest. The purpose of this study was to determine whole-brain GM and WM changes in TLE and to investigate the relationship between these abnormalities and clinical parameters. We studied 85 patients with pharmacologically intractable TLE and unilateral hippocampal atrophy and 47 age- and sex-matched healthy control subjects. The seizure focus was right sided in 40 patients and left sided in 45. Student's t test statistical maps of differences between patients' and controls' GM and WM concentrations were obtained using a general linear model. A further regression against duration of epilepsy, age of onset, presence of febrile convulsions, and secondary generalized seizures was performed with the TLE population. Voxel-based morphometry revealed that GM pathology in TLE extends beyond the hippocampus involving other limbic areas such as the cingulum and the thalamus, as well as extralimbic areas, particularly the frontal lobe. White matter reduction was found only ipsilateral to the seizure focus, including the temporopolar, entorhinal, and perirhinal areas. This pattern of structural changes is suggestive of disconnection involving preferentially frontolimbic pathways in patients with pharmacologically intractable TLE.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Neurosurgery and Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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Bernasconi A, Bernasconi N, Natsume J, Antel SB, Andermann F, Arnold DL. Magnetic resonance spectroscopy and imaging of the thalamus in idiopathic generalized epilepsy. Brain 2003; 126:2447-54. [PMID: 12902313 DOI: 10.1093/brain/awg249] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Experimental work in animal models of generalized epilepsy and clinical data in humans with idiopathic generalized epilepsy (IGE) indicate that the thalamo-cortical circuitry is involved in the generation of epileptic activity. The purpose of this study was to evaluate in vivo the chemical and structural integrity of the thalamus in patients with IGE. Thalamic proton magnetic resonance spectroscopic imaging (1H-MRSI), measuring N-acetylaspartate (NAA), choline-containing compounds and creatine (Cr) was performed in 20 IGE patients and in a group of age-matched healthy subjects. Additionally, 1H-MRSI measurements were taken in the insular cortex, the posterior temporal lobe white matter and the splenium of the corpus callosum. MRI volumetric analysis of the thalamus was performed in all patients. At the time of the examination, seizures were well controlled in 10 IGE patients and poorly controlled in nine. One patient was newly diagnosed and had the MRI and MRSI examination prior to starting the antiepileptic medication. In IGE patients, 1H-MRSI showed a reduction of mean thalamic NAA/Cr compared with normal controls; no difference was found in NAA/Cr in the other examined areas. There was no difference in NAA/Cr between patients whose seizures were well controlled and those in whom seizures were not controlled. There was no correlation between thalamic NAA/Cr and mean number of spike and wave complexes. We found a significant negative correlation between thalamic NAA/Cr and duration of epilepsy. The mean thalamic volume in patients with IGE was not different from normal controls. These results show evidence of progressive thalamic neuronal dysfunction in patients with IGE supporting the notion of abnormal thalamo-cortical circuitry as a substrate of seizure generation in this form of epilepsy. The thalamic dysfunction may occur regardless of amount of spike and wave activity.
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Affiliation(s)
- A Bernasconi
- Department of Neurology and Neurosurgery, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
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Natsume J, Kumakura Y, Bernasconi N, Soucy JP, Nakai A, Rosa P, Fedi M, Dubeau F, Andermann F, Lisbona R, Bernasconi A, Diksic M. Alpha-[11C] methyl-L-tryptophan and glucose metabolism in patients with temporal lobe epilepsy. Neurology 2003; 60:756-61. [PMID: 12629229 DOI: 10.1212/01.wnl.0000052682.99812.f5] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether metabolism in the brain serotonergic system, including the kynurenine pathway, is involved in temporal lobe epilepsy (TLE). METHODS The authors studied 14 patients with intractable TLE by PET using alpha-[11C] methyl-L-tryptophan (alpha-MTrp) and 2-[18F]-fluoro-deoxy-glucose (FDG) and compared results with 21 healthy control subjects who had alpha-MTrp PET studies. Seven patients had unilateral hippocampal atrophy (HA), and seven had normal hippocampal volumes (NV). The regional uptake constant (K*) for alpha-MTrp and regional FDG uptake were calculated in regions with high serotonergic innervation, including the hippocampus, amygdala, lateral temporal lobe, frontal lobe, thalamus, lenticular nucleus, and cingulate cortex. RESULTS A significant increase of alpha-MTrp uptake was observed in the hippocampus ipsilateral to the seizure focus in seven TLE patients with NV compared to seven patients with HA as well as to healthy controls. In patients with TLE, glucose utilization in the lateral temporal lobe ipsilateral to the seizure focus was correlated negatively with K* for alpha-MTrp in the ipsilateral hippocampus and positively with K* in the ipsilateral lenticular nucleus and cingulate cortex. Glucose utilization in the frontal lobe ipsilateral to the seizure shows a reduction in the glucose utilization which relates to the increase in the alpha-MTrp uptake in the ipsilateral lateral temporal lobe. CONCLUSION This study demonstrates dysfunction of the serotonergic system, which could include metabolism through the kynurenine pathway in TLE patients with normal hippocampal volumes. alpha-MTrp PET studies might be useful for lateralizing the epileptic focus in TLE patients with normal hippocampal volumes.
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Affiliation(s)
- J Natsume
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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Bernasconi N, Bernasconi A, Caramanos Z, Antel SB, Andermann F, Arnold DL. Mesial temporal damage in temporal lobe epilepsy: a volumetric MRI study of the hippocampus, amygdala and parahippocampal region. Brain 2003; 126:462-9. [PMID: 12538412 DOI: 10.1093/brain/awg034] [Citation(s) in RCA: 334] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite neuropathological and electrophysiological evidence for the involvement of parahippocampal structures in temporal lobe epilepsy (TLE), little attention has been paid to morphometric measurements of these structures in patients with TLE. Using high resolution MRI, we previously showed that the volume of the entorhinal cortex was decreased in patients with TLE. The purpose of this study was: (i) to determine whether changes in the volume of the perirhinal cortex and posterior parahippocampal cortex were detectable by MRI; and (ii) to study the distribution and degree of atrophy in mesial temporal structures including the hippocampal head, body and tail, amygdala, entorhinal cortex, perirhinal cortex and posterior parahippocampal cortex. MRI volumetric analysis was performed using a T(1)-weighted three-dimensional gradient echo sequence in 20 healthy subjects and 25 TLE patients with intractable TLE. In patients with either left or right TLE, the hippocampal head, body and tail and the entorhinal and perirhinal cortices ipsilateral to the seizure focus were significantly smaller than in normal controls. The mean volume of the posterior parahippocampal cortex was not different from that of normal controls. Within the hippocampus, the hippocampal head was more atrophic than the hippocampal body and hippocampal tail. Within the parahippocampal region, the entorhinal cortex was more severely affected than the perirhinal cortex. Our MRI results confirm pathological findings of damage in the mesial temporal lobe, involving not only the hippocampus and the amygdala, but also the entorhinal and perirhinal cortices. The pattern of atrophy may be explained by cell loss secondary to a disruption of entorhinal-hippocampal connections as a result of privileged electrical dialogue between these two structures.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Neurosurgery, McGill University and Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
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Bernasconi A, Martinez V, Rosa-Neto P, D'Agostino D, Bernasconi N, Berkovic S, MacKay M, Harvey AS, Palmini A, da Costa JC, Paglioli E, Kim HI, Connolly M, Olivier A, Dubeau F, Andermann E, Guerrini R, Whisler W, de Toledo-Morrell L, Morrell F, Andermann F. Surgical resection for intractable epilepsy in "double cortex" syndrome yields inadequate results. Epilepsia 2001; 42:1124-9. [PMID: 11580758 DOI: 10.1046/j.1528-1157.2001.39900.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze the results of surgical treatment of intractable epilepsy in patients with subcortical band heterotopia, or double cortex syndrome, a diffuse neuronal migration disorder. METHODS We studied eight patients (five women) with double cortex syndrome and intractable epilepsy. All had a comprehensive presurgical evaluation including prolonged video-EEG recordings and magnetic resonance imaging (MRI). RESULTS All patients had partial seizures, with secondary generalization in six of them. Neurologic examination was normal in all. Three were of normal intelligence, and five were mildly retarded. Six patients underwent invasive EEG recordings, three of them with subdural grids and three with stereotactic implanted depth electrodes (SEEG). Although EEG recordings showed multilobar epileptic abnormalities in most patients, regional or focal seizure onset was recorded in all. MRI showed bilateral subcortical band heterotopia, asymmetric in thickness in three. An additional area of cortical thickening in the left frontal lobe was found in one patient. Surgical procedures included multiple subpial transections in two patients, frontal lesionectomy in one, temporal lobectomy with amygdalohippocampectomy in five, and an additional anterior callosotomy in one. Five patients had no significant improvement, two had some improvement, and one was greatly improved. CONCLUSION Our results do not support focal surgical removal of epileptogenic tissue in patients with double cortex syndrome, even in the presence of a relatively localized epileptogenic area.
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Affiliation(s)
- A Bernasconi
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, Quebec, Canada.
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Bernasconi N, Bernasconi A, Caramanos Z, Dubeau F, Richardson J, Andermann F, Arnold DL. Entorhinal cortex atrophy in epilepsy patients exhibiting normal hippocampal volumes. Neurology 2001; 56:1335-9. [PMID: 11376184 DOI: 10.1212/wnl.56.10.1335] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether MRI volumetric measurement of the entorhinal cortex could detect structural damage and lateralize the seizure focus in patients with temporal lobe epilepsy in whom no measurable hippocampal abnormalities were found. BACKGROUND A reduction in the volume of the entorhinal cortex ipsilateral to the seizure focus in patients with intractable temporal lobe epilepsy and hippocampal atrophy was recently shown. METHODS MRI volumetric analysis of the entorhinal cortex was performed using a T1-weighted three-dimensional gradient echo sequence in 24 control subjects and 22 patients with temporal lobe epilepsy and normal hippocampal volumes. Thirteen patients underwent surgery, with a mean postoperative follow-up of 36 months. RESULTS Group analysis (multivariate analysis of variance) showed a reduction in the volume of the entorhinal cortex ipsilateral to the seizure focus in patients with left (p < 0.0001) and right temporal lobe epilepsy (p < 0.0001). Lateralization of the seizure focus could be done in 14 of 22 patients (64%) based on entorhinal cortex volumetry. CONCLUSION Entorhinal cortex atrophy ipsilateral to the seizure focus supports the presence of structural damage in the mesial temporal lobe in patients with temporal lobe epilepsy and normal hippocampal volumes and emphasizes the participation of the entorhinal cortex in the pathogenesis of this disorder.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Neurosurgery, McGill University, and Montreal Neurological Institute and Hospital, PQ, Canada
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Bernasconi A, Antel SB, Collins DL, Bernasconi N, Olivier A, Dubeau F, Pike GB, Andermann F, Arnold DL. Texture analysis and morphological processing of magnetic resonance imaging assist detection of focal cortical dysplasia in extra-temporal partial epilepsy. Ann Neurol 2001; 49:770-5. [PMID: 11409429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In many patients, focal cortical dysplasia (FCD) is characterized by minor structural changes that may go unrecognized by standard radiological analysis. To increase the sensitivity of magnetic resonance imaging (MRI) for the detection of subtle lesions of FCD, we developed voxel-based image postprocessing methods, including first-order texture analysis and morphological processing modeled on known MRI features of FCD. We selected 16 patients with histologically proven FCD. Image processing features were calculated over a neighborhood for each voxel in the three-dimensional T1-weighted MRI. Three feature maps were generated: (1) gray matter thickness map to model cortical thickening, (2) gradient map to model blurring of the gray matter-white matter junction, and (3) relative intensity map to model the hyperintense signal within the lesion. Two observers detected lesions on conventional MRI in 8/16 and on ratio maps in 14/16 patients. Sensitivity was 87.5% (14/16) for the ratio maps compared to 50% (8/16) for MRI (p < 0.003). Specificity was 95% (19/20) for ratio maps and 100% (20/20) for MRIs. Cohen's kappa was 0.53 for MRIs, indicating moderate agreement, and 0.83 for ratio maps, indicating strong agreement beyond chance between the 2 observers. The image-processing methods developed in this study improve visual detection of FCD, even in cases where no lesion is obvious on MRI. These techniques could increase the number of patients with partial epilepsy who could benefit from surgery.
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Affiliation(s)
- A Bernasconi
- Department of Neurology and Neurosurgery and Brain Imaging Center, Montreal Neurological Hospital and Institute, McGill University, Montreal, Quebec, Canada
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Bernasconi A, Andermann F, Bernasconi N, Reutens DC, Dubeau F. Lateralizing value of peri-ictal headache: A study of 100 patients with partial epilepsy. Neurology 2001; 56:130-2. [PMID: 11148254 DOI: 10.1212/wnl.56.1.130] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
To determine the lateralizing value of peri-ictal headache, the authors conducted a standardized interview of 100 patients with partial epilepsy, 60 with temporal lobe epilepsy (TLE) and 40 with extratemporal epilepsy (ETE). Peri-ictal headache occurred in 47 of 100 (47%) patients. Peri-ictal headache was more likely to be ipsilateral to the seizure onset in TLE (27 of 30 = 90%) than in ETE (two of 17 = 12%; p< 0.001). For both groups, peri-ictal headache usually conformed to the diagnostic criteria for common migraine (18 of 30 = 60% in TLE; 7 of 17 = 41% in ETE).
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Affiliation(s)
- A Bernasconi
- Departments of Neurology and Neurosurgery, McGill University, and Montreal Neurological Institute and Hospital, Quebec, Canada
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Bernasconi A, Bernasconi N, Caramanos Z, Reutens DC, Andermann F, Dubeau F, Tampieri D, Pike BG, Arnold DL. T2 relaxometry can lateralize mesial temporal lobe epilepsy in patients with normal MRI. Neuroimage 2000; 12:739-46. [PMID: 11112405 DOI: 10.1006/nimg.2000.0724] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In unselected patients with intractable temporal lobe epilepsy (TLE), approximately 15% do not have detectable hippocampal atrophy on MRI. The purpose of this study was to evaluate whether T2 relaxometry can identify hippocampal pathology and lateralize the epileptic focus in patients with intractable TLE, who do not demonstrate hippocampal atrophy on volumetric MRI (MRIV). We selected 14 patients with unilateral TLE who had unilateral atrophy and 11 patients with unilateral TLE who had no evidence of atrophy on MRIV. Images were acquired on a 1.5 T MR scan using a dual echo sequence with 23 contiguous oblique coronal slices in all patients and in 14 healthy subjects. Fitting a single exponential decay equation to the imaging data generated T2 maps. Averages of six slices containing the head, body, and tail of the hippocampus were used to calculate hippocampal T2 relaxation times (HT2). The epileptic focus was defined by history, video-EEG, and surgical response. All TLE patients with hippocampal atrophy and 9/11 (82%) patients with normal MRI had abnormally high HT2 ipsilateral to the epileptic focus. Bilateral abnormal HT2 were found in 6/14 (43%) of patients with unilateral hippocampal atrophy and 2/11 (18%) of patients with normal MRI. However, this increase was always greater ipsilateral to the epileptic focus. Qualitative hippocampal pathology showed gliosis and neuronal loss in 10/14 operated patients with hippocampal atrophy on MRIV and in 5/7 operated patients with normal MRI. In conclusion, hippocampal T2 mapping provides evidence of hippocampal damage in the majority of patients with intractable TLE who have no evidence of atrophy on MRI and can correctly lateralize the epileptic focus in most patients.
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Affiliation(s)
- A Bernasconi
- Department of Neurology, Neurosurgery and Radiology, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
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Bernasconi A, Bernasconi N, Lassonde M, Toussaint PJ, Meyer E, Reutens DC, Gotman J, Andermann F, Villemure JG. Sensorimotor organization in patients who have undergone hemispherectomy: a study with (15)O-water PET and somatosensory evoked potentials. Neuroreport 2000; 11:3085-90. [PMID: 11043528 DOI: 10.1097/00001756-200009280-00010] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To identify cortical structures that subserve residual motor and sensory function in patients with congenital hemiparesis due to a porencephalic cyst, we examined, using [(15)O]H2O, PET and somatosensory evoked potentials (SEPs) in three patients with left-sided hemiparesis who had undergone hemispherectomy. Motor stimulation of the affected hand produced ipsilateral activation in the premotor area in all patients, the SMA in two patients, and SII in two patients. Vibrotactile stimulation resulted in activation of the ipsilateral SII in all subjects. Median nerve stimulation of the affected hand produced ipsilateral long-latency SEPs in fronto-centro-parietal areas, whereas stimulation of the non-affected hand produced normal early cortical potentials in the contralateral hemisphere. Our results suggest that residual function in the paretic hand is warranted through non-primary motor and sensory areas, and higher order associative areas in the intact hemisphere.
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Affiliation(s)
- A Bernasconi
- Montreal Neurological Hospital and Institute, Department of Neurology and Brain Imaging Center, McGill University, Quebec, Canada
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Bernasconi N, Bernasconi A, Caramanos Z, Andermann F, Dubeau F, Arnold DL. Morphometric MRI analysis of the parahippocampal region in temporal lobe epilepsy. Ann N Y Acad Sci 2000; 911:495-500. [PMID: 10911900 DOI: 10.1111/j.1749-6632.2000.tb06752.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Despite neuropathological and electrophysiological evidence for the involvement of parahippocampal structures in temporal lobe epilepsy (TLE), little attention has been paid to morphometric changes in these structures, and the relation of these changes to TLE. We performed high-resolution MRI volumetric analysis to examine in vivo the morphology of the parahippocampal region in 20 healthy subjects and 6 TLE patients with MRI evidence of unilateral hippocampal atrophy. In normal controls the standardized volume of the left entorhinal cortex (EC) was 1305 +/- 138 mm3 and that of the right EC was 1376 +/- 170 mm3; the left perirhinal cortex (PC) was 2900 +/- 554 mm3 and the right PC was 2771 +/- 486 mm3; the left posterior parahippocampal cortex (PPC) was 2499 +/- 583 mm3 and the right PPC was 2234 +/- 404 mm3. Using a 2 standard deviation cutoff from the mean of normal controls, we found ipsilateral to the seizure focus: (i) a reduction in the volume of the EC in all patients; (ii) a reduction of the PC in 2/6 (33%) patients; (iii) no reduction in the volume of the PPC in any patient. In 3/6 (50%) of patients, the EC was also abnormally small contralateral to the seizure focus. In patients with unilateral TLE, the EC is the most affected structure within the parahippocampal region. Whether this is due to a primary role of the EC in the genesis of TLE or is the consequence of its pivotal position in the reciprocal flow of information between the hippocampus and the neo- and limbic cortices remains to be explored.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada.
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Bernasconi N, Bernasconi A, Andermann F, Dubeau F, Feindel W, Reutens DC. Entorhinal cortex in temporal lobe epilepsy: a quantitative MRI study. Neurology 1999; 52:1870-6. [PMID: 10371536 DOI: 10.1212/wnl.52.9.1870] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The entorhinal cortex (EC) is a distinct anatomic and functional region of the anterior parahippocampal gyrus, which plays a role in seizure generation and propagation in temporal lobe epilepsy (TLE). In tissue resected from TLE patients, cell loss in the EC has been described. OBJECTIVES To develop a standardized protocol for identifying the anatomic boundaries of the EC using high-resolution MRI and to examine morphologic changes of the EC in TLE. METHODS We performed T1-weighted MRIs in 20 patients (7 males) with TLE (mean age 34 years) and 18 normal controls (mean age 26 years). Eleven patients had a left and 9 a right epileptic focus as defined by history, video-EEG, and surgical outcome. The volumes of the EC, the hippocampus, and the amygdala were measured using a standardized MRI protocol. Analysis of variance (ANOVA) was used to examine the effect of seizure focus lateralization and hemisphere on these volumes. An asymmetry ratio [A (%) = 100 x (R-L)/(R+L)/2] was also compared between groups using ANOVA. RESULTS In normal controls the volume of the right EC was 1,247 +/- 127 mm3 (mean +/- standard deviation), and that of the left EC was 1,215 +/- 135 mm3 (p > 0.05). We found a bilateral reduction in the volume of the EC in TLE patients compared with controls (p < 0.05). Examination of the asymmetry ratios showed that the reduction in volume of the EC was greater ipsilateral to the epileptic focus (p < 0.05). The volumes of the hippocampus and the amygdala were smaller on the side of the focus in TLE patients compared with controls (p < 0.05). CONCLUSIONS With a standardized protocol for the quantitative assessment of the EC, patients with unilateral TLE show bilateral reduction in the volume of the EC. However, this reduction is more severe ipsilateral to the epileptic focus.
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Affiliation(s)
- N Bernasconi
- Department of Neurology and Neurosurgery, McGill University, and Montreal Neurological Institute and Hospital, Quebec, Canada
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Bernasconi A, Bernasconi N, Andermann F, Reutens D. Volumetric Magnetic Resonance Imaging of the Entorhinal Cortex in Temporal Lobe Epilepsy. Neuroimage 1998. [DOI: 10.1016/s1053-8119(18)31528-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Bernasconi N, Bernasconi A, Andermann F, Reutens D. Volumetric Magnetic Resonance Imaging of the Human Entorhinal Cortex. Neuroimage 1998. [DOI: 10.1016/s1053-8119(18)31529-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Bernasconi A, Bernasconi N, Andermann F, Dubeau F, Guberman A, Gobbi G, Olivier A. Celiac disease, bilateral occipital calcifications and intractable epilepsy: mechanisms of seizure origin. Epilepsia 1998; 39:300-6. [PMID: 9578049 DOI: 10.1111/j.1528-1157.1998.tb01377.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To elucidate the mechanisms of seizure origin in patients with celiac disease and bilateral occipital calcifications (CEBOC). Individuals with CEBOC frequently present with occipital lobe seizures, but additional lesions and additional attack patterns may occur. METHODS We studied two men and one woman who had CEBOC. Villous atrophy was revealed in the two patients who underwent duodenal biopsy. All had a comprehensive presurgical evaluation, including prolonged video-EEG recordings. Two had magnetic resonance imaging (MRI) with volumetric study of mesial temporal structures (MRIV). One patient had undergone stereotactic intracranial depth electrode studies (SEEG). RESULTS All patients presented with intractable complex partial seizures. Two had partial simple seizures with visual aura. Neurologic examination was normal; one was of normal intelligence, and two were mildly retarded. Neuroimaging studies showed that each had bilateral occipital calcifications as well as epileptiform abnormalities over temporal lobes. In one, MRI showed an additional right frontal lesion, but SEEG demonstrated right occipital lobe seizure origin with anterior spread; this male patient later underwent a right occipital lobe resection. Another with a history of prolonged febrile convulsions had bilateral hippocampal and amygdalar atrophy demonstrated by MRIV. CONCLUSIONS In one patient, SEEG confirmed that seizures originated in the occipital lobe. The presence of dual pathology was demonstrated in another, raising the possibility of both occipital and temporal seizure onset. The presence of extraoccipital lesions or of mesial temporal atrophy requires SEEG for clarification of seizure onset. In the absence of confounding factors and when laterality can be demonstrated, surgical treatment may be considered.
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Affiliation(s)
- A Bernasconi
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Quebec, Canada
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