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Westerhausen R. Interhemispheric Integration after Callosotomy: A Meta-Analysis of Poffenberger and Redundant-Target Paradigms. Neuropsychol Rev 2023; 33:872-890. [PMID: 36484870 PMCID: PMC10769931 DOI: 10.1007/s11065-022-09569-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 11/16/2022] [Indexed: 12/13/2022]
Abstract
The central role of the corpus callosum in integrating perception and cognition across the cerebral hemispheres makes it highly desirable for clinical and basic research to have a repertoire of experimental paradigms assessing callosal functioning. Here, the objective was to assess the validity of two such paradigms (Poffenberger, redundant-target paradigms) by conducting single-step meta-analyses on individual case data of callosotomy patients. Studies were identified by systematic literature search (source: Pubmed and WebOfKnowledge, date: 07.03.2022) and all studies were included that reported callosotomy case data for either paradigm. Twenty-two studies (38 unique cases) provided 116 observations of the crossed-uncrossed difference (CUD) for the Poffenberger paradigm, while ten studies (22 cases, 103 observations) provided bilateral redundancy gain (bRG) measures. Using linear-mixed models with "individual" and "experiment" as random-effects variable, the mean CUD was estimated at 60.6 ms (CI95%: 45.3; 75.9) for commissurotomy, 43.5 ms (26.7; 60.2) for complete callosotomy, and 8.8 ms (1.1; 16.6) for partial anterior-medial callosotomy patients. The estimates of commissurotomy/callosotomy patients differed significantly from patients with partial callosotomy and healthy controls. The mean bRGmin (minimum unilateral reference) was estimated at 42.8 ms (27.1;58.4) for patients with complete and 30.8 ms (16.8; 44.7) for patients with partial callosotomy, both differing significantly from controls. One limitation was that different formulas for bRG were used, making it necessary to split the sample and reducing test power of some analyses. Nevertheless, the present findings suggest that both paradigms assess interhemispheric callosal integration, confirming their construct validity, but likely test distinct callosal functions.
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Affiliation(s)
- René Westerhausen
- Section for Cognitive and Clinical Neuroscience, Department of Psychology, University of Oslo, POB 1094 Blindern, Oslo, 0317, Norway.
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2
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Dedeoglu Ö, Altaş H, Yılmaz D, Gürkaş E, Gülleroğlu B, Ekşioğlu S, Çıtak Kurt N. Corpus callosum thickness: A predictive factor for the first drug efficiency of self-limited epilepsy with centrotemporal spikes (selects)? Epilepsy Res 2023; 190:107072. [PMID: 36628885 DOI: 10.1016/j.eplepsyres.2022.107072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/07/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the existence of a possible linkage between the thickness of corpus callosum (CC) regions and the first antiepileptic drug response in patients with Selects. MATERIALS AND METHODS CC thickness of 68 patients with Selects and 42 healthy controls between 4 and 12 years of age were measured using brain magnetic resonance imaging (MRI). Clinical and EEG features of newly diagnosed Selects patients were recorded. Patients were divided into two groups: good-response (patients without seizures within 24 weeks) and poor-response (patients with ≥ 1 seizure within 24 weeks). Thickness of CC was compared between patients (good-response and poor-response groups).and healthy controls. RESULTS The thicknesses of genu and isthmus were significantly reduced in the Selects group than healthy controls. Isthmus and splenium were significantly thinner in poor responders than those in the good-response group (p = 0.005 and p < 0.001, respectively). The total number of seizures was negatively correlated with the thickness of the body, isthmus, and splenium (p < 0.001). There was no significant difference in CC thickness of the children with and without electrical status epilepticus in sleep (ESES). The thickness of the isthmus and splenium were significantly thinner in patients receiving ≥ 2 antiepileptic drugs (p = 0.002 and p = 0.001, respectively). CONCLUSIONS Our study highlights the notable differences in areas of CC in Selects patients. These changes may help uncover the underlying cause of seizure recurrence and antiepileptic drug (AED) response. Different thinner parts of CC may be a protective mechanism to prevent seizure spread to other brain regions. CC thickness can be used as a new radiologic biomarker for predicting first AED response and seizure recurrence in Selects patients.
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Affiliation(s)
- Özge Dedeoglu
- Department of Pediatric Neurology, Ankara State Hospital, Ankara, Turkey.
| | - Hilal Altaş
- Department of Pediatric Neurology, Ankara State Hospital, Ankara, Turkey
| | - Deniz Yılmaz
- Department of Pediatric Neurology, Ankara State Hospital, Ankara, Turkey.
| | - Esra Gürkaş
- Department of Pediatric Neurology, Ankara State Hospital, Ankara, Turkey.
| | - Başak Gülleroğlu
- Department of Pediatric Radiology, Ankara State Hospital, Ankara, Turkey.
| | - Seçil Ekşioğlu
- Department of Pediatric Radiology, Ankara State Hospital, Ankara, Turkey.
| | - Neşe Çıtak Kurt
- Department of Pediatric Neurology, Ankara State Hospital, Ankara, Turkey.
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3
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Bartoňová M, Tournier JD, Bartoň M, Říha P, Vojtíšek L, Mareček R, Doležalová I, Rektor I. White matter alterations in MR-negative temporal and frontal lobe epilepsy using fixel-based analysis. Sci Rep 2023; 13:19. [PMID: 36593331 PMCID: PMC9807578 DOI: 10.1038/s41598-022-27233-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023] Open
Abstract
This study focuses on white matter alterations in pharmacoresistant epilepsy patients with no visible lesions in the temporal and frontal lobes on clinical MRI (i.e. MR-negative) with lesions confirmed by resective surgery. The aim of the study was to extend the knowledge about group-specific neuropathology in MR-negative epilepsy. We used the fixel-based analysis (FBA) that overcomes the limitations of traditional diffusion tensor image analysis, mainly within-voxel averaging of multiple crossing fibres. Group-wise comparisons of fixel parameters between healthy controls (N = 100) and: (1) frontal lobe epilepsy (FLE) patients (N = 9); (2) temporal lobe epilepsy (TLE) patients (N = 13) were performed. A significant decrease of the cross-section area of the fixels in the superior longitudinal fasciculus was observed in the FLE. Results in TLE reflected widespread atrophy of limbic, thalamic, and cortico-striatal connections and tracts directly connected to the temporal lobe (such as the anterior commissure, inferior fronto-occipital fasciculus, uncinate fasciculus, splenium of corpus callosum, and cingulum bundle). Alterations were also observed in extratemporal connections (brainstem connection, commissural fibres, and parts of the superior longitudinal fasciculus). To our knowledge, this is the first study to use an advanced FBA method not only on the datasets of MR-negative TLE patients, but also MR-negative FLE patients, uncovering new common tract-specific alterations on the group level.
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Affiliation(s)
- Michaela Bartoňová
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic ,grid.10267.320000 0001 2194 0956Brno Epilepsy Center, First Department of Neurology, St. Anne’s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jacques-Donald Tournier
- grid.13097.3c0000 0001 2322 6764Centre for Medical Engineering, King’s College London, London, UK ,grid.13097.3c0000 0001 2322 6764Centre for the Developing Brain, King’s College London, London, UK
| | - Marek Bartoň
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Pavel Říha
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic ,grid.10267.320000 0001 2194 0956Brno Epilepsy Center, First Department of Neurology, St. Anne’s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lubomír Vojtíšek
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Radek Mareček
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Irena Doležalová
- grid.10267.320000 0001 2194 0956Brno Epilepsy Center, First Department of Neurology, St. Anne’s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Ivan Rektor
- grid.10267.320000 0001 2194 0956Central European Institute of Technology (CEITEC), Multimodal and Functional Neuroimaging Research Group, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic ,grid.10267.320000 0001 2194 0956Brno Epilepsy Center, First Department of Neurology, St. Anne’s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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Horsley JJ, Schroeder GM, Thomas RH, de Tisi J, Vos SB, Winston GP, Duncan JS, Wang Y, Taylor PN. Volumetric and structural connectivity abnormalities co-localise in TLE. Neuroimage Clin 2022; 35:103105. [PMID: 35863179 PMCID: PMC9421455 DOI: 10.1016/j.nicl.2022.103105] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/17/2022] [Accepted: 06/29/2022] [Indexed: 12/02/2022]
Abstract
Patients with temporal lobe epilepsy (TLE) exhibit both volumetric and structural connectivity abnormalities relative to healthy controls. How these abnormalities inter-relate and their mechanisms are unclear. We computed grey matter volumetric changes and white matter structural connectivity abnormalities in 144 patients with unilateral TLE and 96 healthy controls. Regional volumes were calculated using T1-weighted MRI, while structural connectivity was derived using white matter fibre tractography from diffusion-weighted MRI. For each regional volume and each connection strength, we calculated the effect size between patient and control groups in a group-level analysis. We then applied hierarchical regression to investigate the relationship between volumetric and structural connectivity abnormalities in individuals. Additionally, we quantified whether abnormalities co-localised within individual patients by computing Dice similarity scores. In TLE, white matter connectivity abnormalities were greater when joining two grey matter regions with abnormal volumes. Similarly, grey matter volumetric abnormalities were greater when joined by abnormal white matter connections. The extent of volumetric and connectivity abnormalities related to epilepsy duration, but co-localisation did not. Co-localisation was primarily driven by neighbouring abnormalities in the ipsilateral hemisphere. Overall, volumetric and structural connectivity abnormalities were related in TLE. Our results suggest that shared mechanisms may underlie changes in both volume and connectivity alterations in patients with TLE.
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Affiliation(s)
- Jonathan J Horsley
- CNNP Lab (www.cnnp-lab.com), Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gabrielle M Schroeder
- CNNP Lab (www.cnnp-lab.com), Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Rhys H Thomas
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jane de Tisi
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Sjoerd B Vos
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Nedlands, Australia; Centre for Medical Image Computing, Computer Science Department, University College London, London, United Kingdom
| | - Gavin P Winston
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Division of Neurology, Department of Medicine, Queen's University, Kingston, Canada
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Yujiang Wang
- CNNP Lab (www.cnnp-lab.com), Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom; Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Peter N Taylor
- CNNP Lab (www.cnnp-lab.com), Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom; Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.
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5
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Slinger G, Otte WM, Braun KPJ, van Diessen E. An updated systematic review and meta-analysis of brain network organization in focal epilepsy: Looking back and forth. Neurosci Biobehav Rev 2021; 132:211-223. [PMID: 34813826 DOI: 10.1016/j.neubiorev.2021.11.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 06/23/2021] [Accepted: 11/17/2021] [Indexed: 01/10/2023]
Abstract
Abnormalities of the brain network organization in focal epilepsy have been extensively quantified. However, the extent and directionality of abnormalities are highly variable and subtype insensitive. We conducted meta-analyses to obtain a more accurate and epilepsy type-specific quantification of the interictal global brain network organization in focal epilepsy. By using random-effects models, we estimated differences in average clustering coefficient, average path length, and modularity between patients with focal epilepsy and controls, based on 45 studies with a total sample size of 1,468 patients and 1,021 controls. Structural networks had a significant lower level of integration in patients with epilepsy as compared to controls, with a standardized mean difference of -0.334 (95 % confidence interval -0.631 to -0.038; p-value 0.027). Functional networks did not differ between patients and controls, except for the beta band clustering coefficient. Our meta-analyses show that differences in the brain network organization are not as well defined as individual studies often propose. We discuss potential pitfalls and suggestions to enhance the yield and clinical value of network studies.
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Affiliation(s)
- Geertruida Slinger
- Department of Child Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands.
| | - Willem M Otte
- Department of Child Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands; Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Kees P J Braun
- Department of Child Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Eric van Diessen
- Department of Child Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
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6
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Rajasekaran AK, Shivashankar N, Sinha S, Saini J, Subbakrishna DK, Satishchandra P. Auditory Temporal Ordering in Patients with Medial Temporal Lobe Epilepsy with and without Hippocampal Sclerosis. Neurol India 2021; 69:414-418. [PMID: 33904465 DOI: 10.4103/0028-3886.314569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Context Temporal lobe epilepsy can affect central auditory processing (CAP) skills. Auditory temporal ordering (ATO) is a CAP skill that can be evaluated using duration pattern test (DPT). Aim The aim is to evaluate ATO in patients with medial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (MTLE + HS) and without hippocampal sclerosis (MTLE-HS) and in their subgroups. Settings and Design It was a prospective cross-sectional behavioral observational study conducted in a tertiary neuropsychiatric hospital. Subjects and Methods The subjects were patients with refractory MTLE (N = 100), comprising 50 "MTLE + HS" patients and 50 "MTLE-HS". Age-range matched normal healthy subjects (n = 50) formed the control group. Both groups were administered duration pattern test (DPT). Statistical Analysis Used Analysis of variance (ANOVA) with post hoc analysis, Dunnett's two-sided and Bonferroni, paired sample t-test, Pearson's correlation, and independent t-test. Results The clinical groups performed significantly poorer than the control group, and however, did not differ significantly between them. The age at onset and the duration of the seizures did not have significant relation with the test measures. Conclusions Patients with "MTLE + HS" as well as those with "MTLE-HS" and their respective subgroups revealed abnormal ATO indicating CAP dysfunction.
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Affiliation(s)
- Aravind K Rajasekaran
- Department of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Nagarajarao Shivashankar
- Department of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Jitender Saini
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
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Wang L, Cai XT, Zu MD, Zhang J, Deng ZR, Wang Y. Decreased Resting-State Functional Connectivity of Periaqueductal Gray in Temporal Lobe Epilepsy Comorbid With Migraine. Front Neurol 2021; 12:636202. [PMID: 34122295 PMCID: PMC8189422 DOI: 10.3389/fneur.2021.636202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/15/2021] [Indexed: 11/29/2022] Open
Abstract
Objective: Patients with temporal lobe epilepsy (TLE) are at high risk for having a comorbid condition of migraine, and these two common diseases are proposed to have some shared pathophysiological mechanisms. Our recent study indicated the dysfunction of periaqueductal gray (PAG), a key pain-modulating structure, contributes to the development of pain hypersensitivity and epileptogenesis in epilepsy. This study is to investigate the functional connectivity of PAG network in epilepsy comorbid with migraine. Methods: Thirty-two patients with TLE, including 16 epilepsy patients without migraine (EwoM) and 16 epilepsy patients with comorbid migraine (EwM), and 14 matched healthy controls (HCs) were recruited and underwent resting functional magnetic resonance imaging (fMRI) scans to measure the resting-state functional connectivity (RsFC) of PAG network. The frequency and severity of migraine attacks were assessed using the Migraine Disability Assessment Questionnaire (MIDAS) and Visual Analog Scale/Score (VAS). In animal experiments, FluoroGold (FG), a retrograde tracing agent, was injected into PPN and its fluorescence detected in vlPAG to trace the neuronal projection from vlPAG to PPN. FG traced neuron number was used to evaluate the neural transmission activity of vlPAG-PPN pathway. The data were processed and analyzed using DPARSF and SPSS17.0 software. Based on the RsFC finding, the excitatory transmission of PAG and the associated brain structure was studied via retrograde tracing in combination with immunohistochemical labeling of excitatory neurons. Results: Compared to HCs group, the RsFC between PAG and the left pedunculopontine nucleus (PPN), between PAG and the corpus callosum (CC), was decreased both in EwoM and EwM group, while the RsFC between PAG and the right PPN was increased only in EwoM group but not in EwM group. Compared to EwoM group, the RsFC between PAG and the right PPN was decreased in EwM group. Furthermore, the RsFC between PAG and PPN was negatively correlated with the frequency and severity of migraine attacks. In animal study, a seizure stimulation induced excitatory transmission from PAG to PPN was decreased in rats with chronic epilepsy as compared to that in normal control rats. Conclusion: The comorbidity of epilepsy and migraine is associated with the decreased RsFC between PAG and PPN.
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Affiliation(s)
- Long Wang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China.,Department of Neurology, The Second People Hospital of Hefei, Hefei, China
| | - Xin-Ting Cai
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Mei-Dan Zu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Juan Zhang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zi-Ru Deng
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yu Wang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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Diamond JM, Diamond BE, Trotta MS, Dembny K, Inati SK, Zaghloul KA. Travelling waves reveal a dynamic seizure source in human focal epilepsy. Brain 2021; 144:1751-1763. [PMID: 33693588 DOI: 10.1093/brain/awab089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/08/2020] [Accepted: 12/23/2020] [Indexed: 11/14/2022] Open
Abstract
Treatment of patients with drug-resistant focal epilepsy relies upon accurate seizure localization. Ictal activity captured by intracranial EEG has traditionally been interpreted to suggest that the underlying cortex is actively involved in seizures. Here, we hypothesize that such activity instead reflects propagated activity from a relatively focal seizure source, even during later time points when ictal activity is more widespread. We used the time differences observed between ictal discharges in adjacent electrodes to estimate the location of the hypothesized focal source and demonstrated that the seizure source, localized in this manner, closely matches the clinically and neurophysiologically determined brain region giving rise to seizures. Moreover, we determined this focal source to be a dynamic entity that moves and evolves over the time course of a seizure. Our results offer an interpretation of ictal activity observed by intracranial EEG that challenges the traditional conceptualization of the seizure source.
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Affiliation(s)
- Joshua M Diamond
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Benjamin E Diamond
- J.P. Morgan AI Research, Corporate and Investment Bank, JP Morgan Chase & Co., New York, NY 10017, USA
| | - Michael S Trotta
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kate Dembny
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sara K Inati
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
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9
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Abstract
Epilepsy is characterized by specific alterations in network organization. The main parameters at the basis of epileptogenic network formation are alterations of cortical thickness, development of pathologic hubs, modification of hub distribution, and white matter alterations. The effect is a reinforcement of brain connectivity in both the epileptogenic zone and the propagation zone. Moreover, the epileptogenic network is characterized by some specific neurophysiologic biomarkers that evidence the tendency of the network itself to shift from an interictal state to an ictal one. The recognition of these features is crucial in planning epilepsy surgery.
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10
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Bao Y, He R, Zeng Q, Zhu P, Zheng R, Xu H. Investigation of microstructural abnormalities in white and gray matter around hippocampus with diffusion tensor imaging (DTI) in temporal lobe epilepsy (TLE). Epilepsy Behav 2018; 83:44-49. [PMID: 29653337 DOI: 10.1016/j.yebeh.2017.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 10/17/2022]
Abstract
OBJECTIVE The objective of this study was to apply diffusion tensor imaging (DTI) to investigate microstructural abnormalities in temporal lobe epilepsy (TLE) with and without hippocampal sclerosis (HS). MATERIALS Totally, 19 patients with TLE with HS and 23 patients with TLE without HS were included. Fiber tracking fibers focused on the parahippocampal cingulum (PHC), cingulate gyrus (CG), and fornix (FORX). Fractional anisotropy (FA) and mean diffusivity (MD) values were obtained, and hippocampal volumes were measured. RESULTS Compared with the contralateral side, for the HS group, FA values of ipsilateral CG and FORX were significantly decreased, and MD value of ipsilateral hippocampus was significantly higher, with significantly declined ipsilateral hippocampal volume. For the MRI-Neg group, FA values of ipsilateral CG, FORX, and hippocampus were significantly decreased, while MD values of ipsilateral FORX and hippocampus were significantly higher. Moreover, for the MRI-Neg group, the FA value of contralateral PHC was significantly decreased. Fractional anisotropy values of ipsilateral CG for both groups were significantly decreased, and FA value of ipsilateral FORX for the HS group was significantly decreased. Furthermore, MD value of ipsilateral hippocampus for the HS group was significantly higher, and FA value of ipsilateral hippocampus for the MRI-Neg group was significantly decreased. In addition, ipsilateral hippocampal volumes for both groups were significantly decreased. Fractional anisotropy value of ipsilateral CG and FORX had a correlation with the seizure frequency. CONCLUSION Diffusion tensor imaging can detect microstructural abnormalities in brain from patients with TLE, which might be hard to find with routine Magnetic Resonance Imaging (MRI) sequence.
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Affiliation(s)
- Yixin Bao
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China; Department of Neurology, No. 2 Hospital of Jiaxing, Jiaxing 314000, Zhejiang, China
| | - Ruqian He
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Qingyi Zeng
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Pan Zhu
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Rongyuan Zheng
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Huiqin Xu
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China.
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11
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Uribe-San-Martín R, Ciampi E, Di Giacomo R, Vásquez M, Cárcamo C, Godoy J, Lo Russo G, Tassi L. Corpus callosum atrophy and post-surgical seizures in temporal lobe epilepsy associated with hippocampal sclerosis. Epilepsy Res 2018; 142:29-35. [PMID: 29549794 DOI: 10.1016/j.eplepsyres.2018.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 02/28/2018] [Accepted: 03/01/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Our aim in this retrospective study was to explore whether corpus callosum atrophy could predict the post-surgical seizure control in patients with temporal lobe epilepsy associated with Hippocampal Sclerosis (HS). METHODS We used the Corpus Callosum Index (CCI) obtained from best mid-sagittal T2/FLAIR or T1-weighted MRI at two time-points, more than one year apart. CCI has been mainly used in Multiple Sclerosis (MS), but not in epilepsy, so we tested the validity of our results performing a proof of concept cohort, incorporating MS patients with and without epilepsy. Then, we explored this measurement in a well-characterized and long-term cohort of patients with temporal lobe epilepsy associated with HS. RESULTS In the proof of concept cohort (MS without epilepsy n:40, and MS with epilepsy, n:15), we found a larger CCI atrophy rate in MS patients with poor epilepsy control vs. MS without epilepsy (p:0.01). Then, in HS patients (n:74), annualized CCI atrophy rate was correlated with the long-term Engel scale (Rho:0.31, p:0.007). In patients with post-surgical seizure recurrence, a larger CCI atrophy rate was found one year before any seizure relapse. Univariate analysis showed an increased risk of seizure recurrence in males, higher pre-surgical seizure frequency, necessity of invasive EEG monitoring, and higher CCI atrophy rate. Two of these variables were independent predictors in the multivariate analysis, male gender (HR:4.87, p:0.002) and CCI atrophy rate (HR:1.21, p:0.001). CONCLUSION We demonstrated that atrophy of the corpus callosum, using the CCI, is related with poor seizure control in two different neurological disorders presenting with epilepsy, which might suggest that corpus callosum atrophy obtained in early post-surgical follow-up, could be a biomarker for predicting recurrences and guiding treatment plans.
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Affiliation(s)
- Reinaldo Uribe-San-Martín
- Neurology Department, Pontifical Catholic University of Chile, Santiago, Chile; Neurology Service, "Dr. Sótero del Río" Hospital, Santiago, Chile.
| | - Ethel Ciampi
- Neurology Department, Pontifical Catholic University of Chile, Santiago, Chile; Neurology Service, "Dr. Sótero del Río" Hospital, Santiago, Chile
| | - Roberta Di Giacomo
- Department of Neuroscience, Imaging and Clinical Sciences, "G. D́Annunzio" University, Chieti, Italy
| | - Macarena Vásquez
- Neurology Department, Pontifical Catholic University of Chile, Santiago, Chile
| | - Claudia Cárcamo
- Neurology Department, Pontifical Catholic University of Chile, Santiago, Chile
| | - Jaime Godoy
- Neurology Department, Pontifical Catholic University of Chile, Santiago, Chile
| | - Giorgio Lo Russo
- "Claudio Munari" Epilepsy Surgery Centre, Niguarda Hospital, Milano, Italy
| | - Laura Tassi
- "Claudio Munari" Epilepsy Surgery Centre, Niguarda Hospital, Milano, Italy
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Lyra KP, Chaim KT, Leite CC, Park EJ, Andrade CS, Passarelli V, Valério RMF, Jorge CL, Castro LHM, Otaduy MCG. Corpus callosum diffusion abnormalities in refractory epilepsy associated with hippocampal sclerosis. Epilepsy Res 2017; 137:112-118. [PMID: 28988018 DOI: 10.1016/j.eplepsyres.2017.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 08/05/2017] [Accepted: 09/16/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To detect by diffusion tensor imaging (DTI) the extent of microstructural integrity changes of the corpus callosum (CC) in patients with hippocampal sclerosis (HS) and to evaluate possible association with clinical characteristics. METHODS Fourty-two patients with temporal lobe epilepsy (TLE) and HS and 30 control subjects were studied with DTI. We grouped patients according to lesion side (left or right) HS. Mean diffusivity (MD), fractional anisotropy (FA), radial (RD) and axial diffusivity (AD) were extracted from five segments in CC midsagittal section obtained by automatic segmentation. CC DTI findings were compared between groups. We also evaluated association of DTI changes and clinical characteristics. RESULTS HS patients displayed decreased FA and increased MD and RD in the anterior, mid-posterior and posterior CC segments, compared to controls. No differences were observed in AD. Patients reporting febrile seizure as the initial precipitating event presented more intense diffusion changes. No differences were seen comparing left and right HS. Age at epilepsy onset, disease duration and seizure frequency were not associated with DTI findings. CONCLUSIONS This is one of the largest series of TLE-HS patients evaluating CC white matter fiber integrity by DTI, which allowed us to study how some clinical characteristics, such as seizure frequency, disease duration and lesion side, are related to CC integrity. Occurrence of febrile seizure was the only factor that had significant impact on tract integrity. Diffusion changes were not restricted to the posterior part of the CC; we observed the same changes for the anterior part of the CC. Diffusion changes were characterized by an increase in RD, while the AD remained intact for all regions of the CC.
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Affiliation(s)
- Katarina P Lyra
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Khallil T Chaim
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Claudia C Leite
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Eun J Park
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Celi S Andrade
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Valmir Passarelli
- Department of Neurology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Rosa M F Valério
- Department of Neurology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Carmen L Jorge
- Department of Neurology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Luiz H M Castro
- Department of Neurology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Maria C G Otaduy
- Department of Radiology and Oncology, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil; LIM44-Laboratory of Magnetic Resonance in Neuroimaging, Clinics Hospital, School of Medicine, University of São Paulo, São Paulo, Brazil.
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13
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Besson P, Bandt SK, Proix T, Lagarde S, Jirsa VK, Ranjeva JP, Bartolomei F, Guye M. Anatomic consistencies across epilepsies: a stereotactic-EEG informed high-resolution structural connectivity study. Brain 2017; 140:2639-2652. [DOI: 10.1093/brain/awx181] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/12/2017] [Indexed: 11/12/2022] Open
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Kim HC, Kim SE, Lee BI, Park KM. Can we predict drug response by volumes of the corpus callosum in newly diagnosed focal epilepsy? Brain Behav 2017; 7:e00751. [PMID: 28828212 PMCID: PMC5561312 DOI: 10.1002/brb3.751] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/08/2017] [Accepted: 05/15/2017] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate whether volumes of the corpus callosum could predict a response to antiepileptic drugs in patients with newly diagnosed focal epilepsy. METHODS Fifty-three patients with newly diagnosed focal epilepsy of unknown etiology and healthy subjects were enrolled in this study. First, we analyzed the differences in the volumes of the corpus callosum between patients with epilepsy and healthy subjects. Second, we divided patients with epilepsy into antiepileptic drug responders and drug nonresponders groups, according to their seizure controls, and evaluated the differences in the volumes of the corpus callosum between the groups. Third, we conducted correlation analyses between the volumes of the corpus callosum and mean diffusion measures in healthy subjects. RESULTS The volumes of the corpus callosum in patients with epilepsy were significantly lower than those in normal controls (p = .0001). Among epilepsy patients, the volumes of the corpus callosum were significantly lower in antiepileptic drug responders compared with nonresponders (p = .0481), which was the only independent variable for predicting antiepileptic drug response (OR = 10.07, p = .0434). In addition, we found that the volumes of the corpus callosum were significantly correlated with the mean diffusion measures (fractional anisotropy, r = .408, p = .0027; mean diffusivity, r = -0.403, p = .0028) in normal controls. CONCLUSIONS We demonstrated that the volumes of the corpus callosum were different according to antiepileptic drug responses in patients with newly diagnosed focal epilepsy, which might suggest that the volumes of the corpus callosum could be a new biomarker for predicting responses to antiepileptic drugs.
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Affiliation(s)
- Hyung Chan Kim
- Department of Neurology Haeundae Paik Hospital Inje University College of Medicine Busan Korea
| | - Sung Eun Kim
- Department of Neurology Haeundae Paik Hospital Inje University College of Medicine Busan Korea
| | - Byung In Lee
- Department of Neurology Haeundae Paik Hospital Inje University College of Medicine Busan Korea
| | - Kang Min Park
- Department of Neurology Haeundae Paik Hospital Inje University College of Medicine Busan Korea
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Chen YJ, Nabavizadeh SA, Vossough A, Kumar S, Loevner LA, Mohan S. Wallerian Degeneration Beyond the Corticospinal Tracts: Conventional and Advanced MRI Findings. J Neuroimaging 2016; 27:272-280. [PMID: 28072502 DOI: 10.1111/jon.12404] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 12/21/2022] Open
Abstract
Wallerian degeneration (WD) is defined as progressive anterograde disintegration of axons and accompanying demyelination after an injury to the proximal axon or cell body. Since the 1980s and 1990s, conventional magnetic resonance imaging (MRI) sequences have been shown to be sensitive to changes of WD in the subacute to chronic phases. More recently, advanced MRI techniques, such as diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI), have demonstrated some of earliest changes attributed to acute WD, typically on the order of days. In addition, there is increasing evidence on the value of advanced MRI techniques in providing important prognostic information related to WD. This article reviews the utility of conventional and advanced MRI techniques for assessing WD, by focusing not only on the corticospinal tract but also other neural tracts less commonly thought of, including corticopontocerebellar tract, dentate-rubro-olivary pathway, posterior column of the spinal cord, corpus callosum, limbic circuit, and optic pathway. The basic anatomy of these neural pathways will be discussed, followed by a comprehensive review of existing literature supported by instructive clinical examples. The goal of this review is for readers to become more familiar with both conventional and advanced MRI findings of WD involving important neural pathways, as well as to illustrate increasing utility of advanced MRI techniques in providing important prognostic information for various pathologies.
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Affiliation(s)
- Yin Jie Chen
- Division of Neuroradiology, Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Seyed Ali Nabavizadeh
- Division of Neuroradiology, Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Arastoo Vossough
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Sunil Kumar
- Department of Radiodiagnosis, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Laurie A Loevner
- Division of Neuroradiology, Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Suyash Mohan
- Division of Neuroradiology, Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
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Nagy SA, Horváth R, Perlaki G, Orsi G, Barsi P, John F, Horváth A, Kovács N, Bogner P, Ábrahám H, Bóné B, Gyimesi C, Dóczi T, Janszky J. Age at onset and seizure frequency affect white matter diffusion coefficient in patients with mesial temporal lobe epilepsy. Epilepsy Behav 2016; 61:14-20. [PMID: 27232377 DOI: 10.1016/j.yebeh.2016.04.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 02/01/2023]
Abstract
In mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), structural abnormalities are present not only in the hippocampus but also in the white matter with ipsilateral predominance. Although the timing of epilepsy onset is commonly associated with clinical and semiological dissimilarities, limited data exist regarding white matter diffusion changes with respect to age at epilepsy onset. The aim of this study was to investigate diffusion changes in the white matter of patients with unilateral MTLE-HS with respect to clinical parameters and to compare them with an age- and sex-matched healthy control group. Apparent diffusion coefficients (ADCs) were derived using monoexponential approaches from 22 (11 early and 11 late age at onset) patients with unilateral MTLE-HS and 22 age- and sex-matched control subjects after acquiring diffusion-weighted images on a 3T MRI system. Data were analyzed using two-tailed t-tests and multiple linear regression models. In the group with early onset MTLE-HS, ADC was significantly elevated in the ipsilateral hemispheric (p=0.04) and temporal lobe white matter (p=0.01) compared with that in controls. These differences were not detectable in late onset MTLE-HS patients. Apparent diffusion coefficient of the group with early onset MTLE-HS was negatively related to age at epilepsy onset in the ipsilateral hemispheric white matter (p=0.03) and the uncinate fasciculus (p=0.03), while in patients with late onset MTLE-HS, ADC was no longer dependent on age at epilepsy onset itself but rather on the seizure frequency in the ipsilateral uncinate fasciculus (p=0.03). Such diffusivity pattern has been associated with chronic white matter degeneration, reflecting myelin loss and higher extracellular volume which are more pronounced in the frontotemporal regions and also depend on clinical features. In the group with early onset MTLE-HS, the timing of epilepsy seems to be the major cause of white matter abnormalities while in late onset disease, it has a secondary role in provoking diffusion changes.
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Affiliation(s)
- Szilvia A Nagy
- Pécs Diagnostics Center, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Neurobiology of Stress Research Group, H-7624 Pécs, Ifjúság Street 20., Hungary.
| | - Réka Horváth
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - Gábor Perlaki
- Pécs Diagnostics Center, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Clinical Neuroscience MR Research Group, H-7623 Pécs, Rét Street 2., Hungary.
| | - Gergely Orsi
- Pécs Diagnostics Center, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Clinical Neuroscience MR Research Group, H-7623 Pécs, Rét Street 2., Hungary.
| | - Péter Barsi
- MR Research Centre, Semmelweis University, H-1083 Budapest, Balassa Street 6., Hungary.
| | - Flóra John
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - Andrea Horváth
- Pécs Diagnostics Center, H-7623 Pécs, Rét Street 2., Hungary; Department of Neurosurgery, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - Norbert Kovács
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Clinical Neuroscience MR Research Group, H-7623 Pécs, Rét Street 2., Hungary.
| | - Péter Bogner
- Department of Radiology, University of Pécs, H-7624 Pécs, Ifjúság Street 13., Hungary.
| | - Hajnalka Ábrahám
- Department of Medical Biology, University of Pécs, H-7624 Pécs, Szigeti Street 12., Hungary; Central Electron Microscopic Laboratory, University of Pécs, H-7624 Pécs, Honvéd Street 1., Hungary.
| | - Beáta Bóné
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - Csilla Gyimesi
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - Tamás Dóczi
- Pécs Diagnostics Center, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Clinical Neuroscience MR Research Group, H-7623 Pécs, Rét Street 2., Hungary; Department of Neurosurgery, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary.
| | - József Janszky
- Department of Neurology, University of Pécs, H-7623 Pécs, Rét Street 2., Hungary; MTA-PTE, Clinical Neuroscience MR Research Group, H-7623 Pécs, Rét Street 2., Hungary.
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Unterberger I, Bauer R, Walser G, Bauer G. Corpus callosum and epilepsies. Seizure 2016; 37:55-60. [DOI: 10.1016/j.seizure.2016.02.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/01/2016] [Accepted: 02/25/2016] [Indexed: 11/16/2022] Open
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Caligiuri ME, Labate A, Cherubini A, Mumoli L, Ferlazzo E, Aguglia U, Quattrone A, Gambardella A. Integrity of the corpus callosum in patients with benign temporal lobe epilepsy. Epilepsia 2016; 57:590-6. [DOI: 10.1111/epi.13339] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Maria Eugenia Caligiuri
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR); Catanzaro Italy
| | - Angelo Labate
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR); Catanzaro Italy
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
| | - Andrea Cherubini
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR); Catanzaro Italy
| | - Laura Mumoli
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
| | - Edoardo Ferlazzo
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
| | - Umberto Aguglia
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
| | - Aldo Quattrone
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR); Catanzaro Italy
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
| | - Antonio Gambardella
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR); Catanzaro Italy
- Institute of Neurology; University Magna Graecia; Catanzaro Italy
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Bradley KA, Juranek J, Romanowska-Pawliczek A, Hannay HJ, Cirino PT, Dennis M, Kramer LA, Fletcher JM. Plasticity of Interhemispheric Temporal Lobe White Matter Pathways Due to Early Disruption of Corpus Callosum Development in Spina Bifida. Brain Connect 2016; 6:238-48. [PMID: 26798959 DOI: 10.1089/brain.2015.0387] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Spina bifida myelomeningocele (SBM) is commonly associated with anomalous development of the corpus callosum (CC) because of congenital partial hypogenesis and hydrocephalus-related hypoplasia. It represents a model disorder to examine the effects of early disruption of CC neurodevelopment and the plasticity of interhemispheric white matter connections. Diffusion tensor imaging was acquired on 76 individuals with SBM and 27 typically developing individuals, aged 8-36 years. Probabilistic tractography was used to isolate the interhemispheric connections between the posterior superior temporal lobes, which typically traverse the posterior third of the CC. Early disruption of CC development resulted in restructuring of interhemispheric connections through alternate commissures, particularly the anterior commissure (AC). These rerouted fibers were present in people with SBM and both CC hypoplasia and hypogenesis. In addition, microstructural integrity was reduced in the interhemispheric temporal tract in people with SBM, indexed by lower fractional anisotropy, axial diffusivity, and higher radial diffusivity. Interhemispheric temporal tract volume was positively correlated with total volume of the CC, such that more severe underdevelopment of the CC was associated with fewer connections between the posterior temporal lobes. Therefore, both the macrostructure and microstructure of this interhemispheric tract were reduced, presumably as a result of more extensive CC malformation. The current findings suggest that early disruption in CC development reroutes interhemispheric temporal fibers through both the AC and more anterior sections of the CC in support of persistent hypotheses that the AC may serve a compensatory function in atypical CC development.
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Affiliation(s)
- Kailyn A Bradley
- 1 Department of Psychology, University of Houston , Houston, Texas.,2 Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jenifer Juranek
- 3 Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center at Houston , Houston, Texas
| | - Anna Romanowska-Pawliczek
- 3 Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center at Houston , Houston, Texas
| | - H Julia Hannay
- 1 Department of Psychology, University of Houston , Houston, Texas
| | - Paul T Cirino
- 1 Department of Psychology, University of Houston , Houston, Texas
| | - Maureen Dennis
- 4 Program in Neurosciences and Mental Health, The Hospital for Sick Children , Toronto, Canada
| | - Larry A Kramer
- 5 Department of Diagnostic and Interventional Radiology, University of Texas Health Science Center at Houston , Houston, Texas
| | - Jack M Fletcher
- 1 Department of Psychology, University of Houston , Houston, Texas
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20
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Nazem-Zadeh MR, Elisevich K, Air EL, Schwalb JM, Divine G, Kaur M, Wasade VS, Mahmoudi F, Shokri S, Bagher-Ebadian H, Soltanian-Zadeh H. DTI-based response-driven modeling of mTLE laterality. NEUROIMAGE-CLINICAL 2015; 11:694-706. [PMID: 27330966 PMCID: PMC4900487 DOI: 10.1016/j.nicl.2015.10.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/25/2015] [Accepted: 10/27/2015] [Indexed: 12/30/2022]
Abstract
Purpose To develop lateralization models for distinguishing between unilateral and bilateral mesial temporal lobe epilepsy (mTLE) and determining laterality in cases of unilateral mTLE. Background mTLE is the most common form of medically refractory focal epilepsy. Many mTLE patients fail to demonstrate an unambiguous unilateral ictal onset. Intracranial EEG (icEEG) monitoring can be performed to establish whether the ictal origin is unilateral or truly bilateral with independent bitemporal ictal origin. However, because of the expense and risk of intracranial electrode placement, much research has been done to determine if the need for icEEG can be obviated with noninvasive neuroimaging methods, such as diffusion tensor imaging (DTI). Methods Fractional anisotropy (FA) was used to quantify microstructural changes reflected in the diffusivity properties of the corpus callosum, cingulum, and fornix, in a retrospective cohort of 31 patients confirmed to have unilateral (n = 24) or bilateral (n = 7) mTLE. All unilateral mTLE patients underwent resection with an Engel class I outcome. Eleven were reported to have hippocampal sclerosis on pathological analysis; nine had undergone prior icEEG. The bilateral mTLE patients had undergone icEEG demonstrating independent epileptiform activity in both right and left hemispheres. Twenty-three nonepileptic subjects were included as controls. Results In cases of right mTLE, FA showed significant differences from control in all callosal subregions, in both left and right superior cingulate subregions, and in forniceal crura. Comparison of right and left mTLE cases showed significant differences in FA of callosal genu, rostral body, and splenium and the right posteroinferior and superior cingulate subregions. In cases of left mTLE, FA showed significant differences from control only in the callosal isthmus. Significant differences in FA were identified when cases of right mTLE were compared with bilateral mTLE cases in the rostral and midbody callosal subregions and isthmus. Based on 11 FA measurements in the cingulate, callosal and forniceal subregions, a response-driven lateralization model successfully differentiated all cases (n = 54) into groups of unilateral right (n = 12), unilateral left (n = 12), and bilateral mTLE (n = 7), and nonepileptic control (23). Conclusion The proposed response-driven DTI biomarker is intended to lessen diagnostic ambiguity of laterality in cases of mTLE and help optimize selection of surgical candidates. Application of this model shows promise in reducing the need for invasive icEEG in prospective cases. Develop response-driven lateralization model using diffusion tensor imaging Distinguish between unilateral and bilateral mesial temporal lobe epilepsy (mTLE) Determine or lessen diagnostic ambiguity of laterality in cases of unilateral mTLE Optimize selection of surgical candidates Reduction of the need for intracranial EEG
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Affiliation(s)
| | - Kost Elisevich
- Department of Clinical Neurosciences, Spectrum Health Medical Group, Division of Neurosurgery, Michigan State University, Grand Rapids, MI 49503, USA
| | - Ellen L Air
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Jason M Schwalb
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - George Divine
- Public Health Sciences Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Manpreet Kaur
- Neurosurgery Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | | | - Fariborz Mahmoudi
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Computer and IT engineering Faculty, Islamic Azad University, Qazvin Branch, Iran.
| | - Saeed Shokri
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; School of Computer Science, Wayne State University, Detroit, MI 48202, USA.
| | - Hassan Bagher-Ebadian
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Neurology Department, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Hamid Soltanian-Zadeh
- Radiology and Research Administration Department, Henry Ford Health System, Detroit, MI 48202, USA; Control and Intelligent Processing Center of Excellence (CIPCE), School of Electrical and Computer, University of Tehran, Tehran, Iran.
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Szmuda M, Szmuda T, Springer J, Rogowska M, Sabisz A, Dubaniewicz M, Mazurkiewicz-Bełdzińska M. Diffusion tensor tractography imaging in pediatric epilepsy - A systematic review. Neurol Neurochir Pol 2015; 50:1-6. [PMID: 26851683 DOI: 10.1016/j.pjnns.2015.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 10/12/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE Recent years brought several experimental and clinical reports applying diffusion tensor tractography imaging (DTI) of the brain in epilepsy. This study was aimed to evaluate current evidence for adding the DTI sequence to the standard diagnostic magnetic resonance imaging (MRI) protocol in pediatric epilepsy. MATERIAL AND METHODS Rapid and qualitative systematic review (RAE, Rapid Evidence Assessment), aggregating relevant studies from the recent 7 years. The PubMed database was hand searched for records containing terms "tractography AND epilepsy." Only studies referring to children were included; studies were rated using "final quality of evidence." RESULTS Out of 144 screened records, relevant 101 were aggregated and reviewed. The synthesis was based on 73 studies. Case-control clinical studies were the majority of the material and comprised 43.8% of the material. Low 'confirmability' and low 'applicability' referred to 18 and 17 articles (29.5% and 27.9%), respectively. The sufficient quality of evidence supported performing DTI in temporal lobe epilepsy, malformations of cortical development and prior to a neurosurgery of epilepsy. CONCLUSIONS The qualitative RAE provides an interim estimate of the clinical relevance of quickly developing diagnostic methods. Based on the critical appraisal of current knowledge, adding the DTI sequence to the standard MRI protocol may be clinically beneficial in selected patient groups with childhood temporal lobe epilepsy or as a part of planning for an epilepsy surgery.
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Affiliation(s)
- Marta Szmuda
- Department of Developmental Neurology, Medical University of Gdańsk, Gdańsk, Poland.
| | - Tomasz Szmuda
- Department of Neurosurgery, Medical University of Gdańsk, Gdańsk, Poland.
| | - Janusz Springer
- Department of Preventive Medicine and Education, Medical University of Gdańsk, Gdańsk, Poland.
| | - Marianna Rogowska
- Department of Neurosurgery, Medical University of Gdańsk, Gdańsk, Poland.
| | - Agnieszka Sabisz
- Department of Radiology, Medical University of Gdańsk, Gdańsk, Poland.
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Demonstration of Differentially Degenerated Corpus Callosam in Patients With Moderate Traumatic Brain Injury: With a Premise of Cortical-callosal Relationship. ARCHIVES OF NEUROSCIENCE 2015. [DOI: 10.5812/archneurosci.27768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Decreased white matter integrity in mesial temporal lobe epilepsy: a machine learning approach. Neuroreport 2015; 25:788-94. [PMID: 24918460 DOI: 10.1097/wnr.0000000000000178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Statistical analysis on diffusion tensor imaging has been used extensively in mesial temporal lobe epilepsy (mTLE) and most studies report decrease in fractional anisotropy (FA) in multiple white matter regions. However, these findings vary across studies and between regions. Therefore, in this study, we used tract-based spatial statistics along with machine learning approaches to investigate the whole-brain white matter changes between 17 left mTLE patients and 15 right mTLE patients and 34 matched healthy controls. The results showed that the three groups could be distinguished from each other with promising accuracy. Compared with controls, the FA value of the most discriminating voxels was decreased in the ipsilateral limbic system, corpus callosum, and temporal white matter in both patient groups. Compared with right mTLE, left mTLE had decreased FA in the left temporal white matter, whereas right mTLE had decreased FA in the right frontal and temporal white matter, and right posterior corona radiata. These findings not only provide useful information for lateralization of the seizure focus but can also be used as a potential biomarker for the diagnosis and treatment of the mTLE. This may be helpful in assessment of patients with mTLE when no lesion is detected on visual evaluation.
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Blackmon K, Pardoe HR, Barr WB, Ardekani BA, Doyle WK, Devinsky O, Kuzniecky R, Thesen T. The corpus callosum and recovery of working memory after epilepsy surgery. Epilepsia 2015; 56:527-34. [PMID: 25684448 DOI: 10.1111/epi.12931] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE For patients with medically intractable focal epilepsy, the benefit of epilepsy surgery must be weighed against the risk of cognitive decline. Clinical factors such as age and presurgical cognitive level partially predict cognitive outcome; yet, little is known about the role of cross-hemispheric white matter pathways in supporting postsurgical recovery of cognitive function. The purpose of this study is to determine whether the presurgical corpus callosum (CC) midsagittal area is associated with pre- to postsurgical change following epilepsy surgery. METHODS In this observational study, we retrospectively identified 24 adult patients from an epilepsy resection series who completed preoperative high-resolution T1 -weighted magnetic resonance imaging (MRI) scans, as well as pre- and postsurgical neuropsychological testing. The total area and seven subregional areas of the CC were measured on the midsagittal MRI slice using an automated method. Standardized indices of auditory-verbal working memory and delayed memory were used to probe cognitive change from pre- to postsurgery. CC total and subregional areas were regressed on memory-change scores, after controlling for overall brain volume, age, presurgical memory scores, and duration of epilepsy. RESULTS Patients had significantly reduced CC area relative to healthy controls. We found a positive relationship between CC area and change in working memory, but not delayed memory; specifically, the larger the CC, the greater the postsurgical improvement in working memory (β = 0.523; p = 0.009). Effects were strongest in posterior CC subregions. There was no relationship between CC area and presurgical memory scores. SIGNIFICANCE Findings indicate that larger CC area, measured presurgically, is related to improvement in working memory abilities following epilepsy surgery. This suggests that transcallosal pathways may play an important, yet little understood, role in postsurgical recovery of cognitive functions.
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Affiliation(s)
- Karen Blackmon
- Department of Neurology, Comprehensive Epilepsy Center, New York University School of Medicine, New York, New York, U.S.A
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van Diessen E, Zweiphenning WJEM, Jansen FE, Stam CJ, Braun KPJ, Otte WM. Brain Network Organization in Focal Epilepsy: A Systematic Review and Meta-Analysis. PLoS One 2014; 9:e114606. [PMID: 25493432 PMCID: PMC4262431 DOI: 10.1371/journal.pone.0114606] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 11/12/2014] [Indexed: 12/17/2022] Open
Abstract
Normal brain functioning is presumed to depend upon interacting regions within large-scale neuronal networks. Increasing evidence exists that interictal network alterations in focal epilepsy are associated with cognitive and behavioral deficits. Nevertheless, the reported network alterations are inconclusive and prone to low statistical power due to small sample sizes as well as modest effect sizes. We therefore systematically reviewed the existing literature and conducted a meta-analysis to characterize the changes in whole-brain interictal focal epilepsy networks at sufficient power levels. We focused on the two most commonly used metrics in whole-brain networks: average path length and average clustering coefficient. Twelve studies were included that reported whole-brain network average path length and average clustering coefficient characteristics in patients and controls. The overall group difference, quantified as the standardized mean average path length difference between epilepsy and control groups, corresponded to a significantly increased average path length of 0.29 (95% confidence interval (CI): 0.12 to 0.45, p = 0.0007) in the epilepsy group. This suggests a less integrated interictal whole-brain network. Similarly, a significantly increased standardized mean average clustering coefficient of 0.35 (CI: 0.05 to 0.65, p = 0.02) was found in the epilepsy group in comparison with controls, pointing towards a more segregated interictal network. Sub-analyses revealed similar results for functional and structural networks in terms of effect size and directionality for both metrics. In addition, we found individual network studies to be prone to low power due to the relatively small group differences in average path length and average clustering coefficient in combination with small sample sizes. The pooled network characteristics support the hypothesis that focal epilepsy has widespread detrimental effects, that is, reduced integration and increased segregation, on whole brain interictal network organization, which may relate to the co-morbid cognitive and behavioral impairments often reported in patients with focal epilepsy.
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Affiliation(s)
- Eric van Diessen
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
| | | | - Floor E. Jansen
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelis J. Stam
- Department of Clinical Neurophysiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Kees P. J. Braun
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willem M. Otte
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
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Chaudhary UJ, Duncan JS. Applications of blood-oxygen-level-dependent functional magnetic resonance imaging and diffusion tensor imaging in epilepsy. Neuroimaging Clin N Am 2014; 24:671-94. [PMID: 25441507 DOI: 10.1016/j.nic.2014.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The lifetime prevalence of epilepsy ranges from 2.7 to 12.4 per 1000 in Western countries. Around 30% of patients with epilepsy remain refractory to antiepileptic drugs and continue to have seizures. Noninvasive imaging techniques such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have helped to better understand mechanisms of seizure generation and propagation, and to localize epileptic, eloquent, and cognitive networks. In this review, the clinical applications of fMRI and DTI are discussed, for mapping cognitive and epileptic networks and organization of white matter tracts in individuals with epilepsy.
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Affiliation(s)
- Umair J Chaudhary
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK.
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK; Queen Square Division, UCLH NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
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Zakszewski E, Adluru N, Tromp DPM, Kalin N, Alexander AL. A diffusion-tensor-based white matter atlas for rhesus macaques. PLoS One 2014; 9:e107398. [PMID: 25203614 PMCID: PMC4159318 DOI: 10.1371/journal.pone.0107398] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 08/11/2014] [Indexed: 01/20/2023] Open
Abstract
Atlases of key white matter (WM) structures in humans are widely available, and are very useful for region of interest (ROI)-based analyses of WM properties. There are histology-based atlases of cortical areas in the rhesus macaque, but none currently of specific WM structures. Since ROI-based analysis of WM pathways is also useful in studies using rhesus diffusion tensor imaging (DTI) data, we have here created an atlas based on a publicly available DTI-based template of young rhesus macaques. The atlas was constructed to mimic the structure of an existing human atlas that is widely used, making results translatable between species. Parcellations were carefully hand-drawn on a principle-direction color-coded fractional anisotropy image of the population template. The resulting atlas can be used as a reference to which registration of individual rhesus data can be performed for the purpose of white-matter parcellation. Alternatively, specific ROIs from the atlas may be warped into individual space to be used in ROI-based group analyses. This atlas will be made publicly available so that it may be used as a resource for DTI studies of rhesus macaques.
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Affiliation(s)
- Elizabeth Zakszewski
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin - Madison, Madison, Wisconsin, United States of America
- Department of Medical Physics, University of Wisconsin - Madison, Wisconsin Institutes for Medical Research, Madison, Wisconsin, United States of America
| | - Nagesh Adluru
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin - Madison, Madison, Wisconsin, United States of America
| | - Do P. M. Tromp
- Health Emotions Research Institute, University of Wisconsin - Madison, Health Emotions Research Institute Madison, Wisconsin, United States of America
| | - Ned Kalin
- Health Emotions Research Institute, University of Wisconsin - Madison, Health Emotions Research Institute Madison, Wisconsin, United States of America
- Department of Psychiatry, University of Wisconsin - Madison, Wisconsin Psychiatric Institute & Clinics, Madison, Wisconsin, United States of America
| | - Andrew L. Alexander
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin - Madison, Madison, Wisconsin, United States of America
- Department of Psychiatry, University of Wisconsin - Madison, Wisconsin Psychiatric Institute & Clinics, Madison, Wisconsin, United States of America
- Department of Medical Physics, University of Wisconsin - Madison, Wisconsin Institutes for Medical Research, Madison, Wisconsin, United States of America
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Lateralization of temporal lobe epilepsy using a novel uncertainty analysis of MR diffusion in hippocampus, cingulum, and fornix, and hippocampal volume and FLAIR intensity. J Neurol Sci 2014; 342:152-61. [PMID: 24857759 DOI: 10.1016/j.jns.2014.05.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/08/2014] [Accepted: 05/06/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze the utility of a quantitative uncertainty analysis approach for evaluation and comparison of various MRI findings for the lateralization of epileptogenicity in mesial temporal lobe epilepsy (mTLE), including novel diffusion-based analyses. METHODS We estimated the hemispheric variation uncertainty (HVU) of hippocampal T1 volumetry and FLAIR (Fluid Attenuated Inversion Recovery) intensity. Using diffusion tensor images of 23 nonepileptic subjects, we estimated the HVU levels of mean diffusivity (MD) in the hippocampus, and fractional anisotropy (FA) in the posteroinferior cingulum and crus of fornix. Imaging from a retrospective cohort of 20 TLE patients who had undergone surgical resection with Engel class I outcomes was analyzed to determine whether asymmetry of preoperative volumetrics, FLAIR intensities, and MD values in hippocampi, as well as FA values in posteroinferior cingula and fornix crura correctly predicted laterality of seizure onset. Ten of the cohort had pathologically proven mesial temporal sclerosis (MTS). Seven of these patients had undergone extraoperative electrocorticography (ECoG) for lateralization or to rule out extra-temporal foci. RESULTS HVU was estimated to be 3.1×10(-5) for hippocampal MD, 0.027 for FA in posteroinferior cingulum, 0.018 for FA in crus of fornix, 0.069 for hippocampal normalized volume, and 0.099 for hippocampal normalized FLAIR intensity. Using HVU analysis, a higher hippocampal MD value, lower FA within the posteroinferior cingulum and crus of fornix, shrinkage in hippocampal volume, and higher hippocampal FLAIR intensity were observed beyond uncertainty on the side ipsilateral to seizure onset for 10, 10, 9, 9, and 10 out of 10 pathology-proven MTS patients, respectively. Considering all 20 TLE patients, these numbers were 18, 15, 14, 13, and 16, respectively. However, consolidating the lateralization results of HVU analysis on these quantities by majority voting has detected the epileptogenic side for 19 out of 20 cases with no wrong lateralization. CONCLUSION The presence of MTS in TLE patients is associated with an elevated MD value in the ipsilateral hippocampus and a reduced FA value in the posteroinferior subregion of the ipsilateral cingulum and crus of ipsilateral fornix. When considering all TLE patients, among the mentioned biomarkers the hippocampal MD had the best performance with true detection rate of 90% without any wrong lateralization. The proposed uncertainty based analyses hold promise for improving decision-making for surgical resection.
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Otte WM, van Meer MPA, van der Marel K, Zwartbol R, Viergever MA, Braun KPJ, Dijkhuizen RM. Experimental focal neocortical epilepsy is associated with reduced white matter volume growth: results from multiparametric MRI analysis. Brain Struct Funct 2013; 220:27-36. [DOI: 10.1007/s00429-013-0633-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 08/30/2013] [Indexed: 10/26/2022]
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Evaluation of corpus callosum morphometry in patients with mesial temporal lobe epilepsy with hippocampal sclerosis. Surg Radiol Anat 2013; 36:47-54. [PMID: 23771402 DOI: 10.1007/s00276-013-1144-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE The purpose of the study was to evaluate the effects of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) on corpus callosum (CC) morphometry in large and pathologically proven MTLE-HS patients. METHODS We measured certain CC dimensions in 103 patients and 33 healthy controls using in vivo magnetic resonance imaging. In particular, we compared the two groups in relation to the clinical (localization of the HS, duration of epilepsy, frequency of seizures and length of seizures) and demographical (age, gender, handedness) features. Students' t test, two-way ANOVA and Spearman test were used for statistical analysis. RESULTS There was no significant difference between CC morphometry with respect to age and handedness among patients. The differences between the genders, however, were significant favouring longer diameters in males. We found significant decrease in the dimensions of the genu, body, isthmus and splenium of the CC in the MTLE-HS group, but there was no reduction in the size of the rostrum. CONCLUSIONS This general reduction in the size of the CC except for the rostrum was thought to be the result of cortical atrophy secondary to the disease. Concerning the preserved rostral part of the CC, it was thought that the fibers of the frontal lobe pass through different pathways than the tracts in the rostrum.
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Saksena S, Jain R, Schultz L, Jiang Q, Soltanian-Zadeh H, Scarpace L, Rosenblum M, Mikkelsen T, Nazem-Zadeh MR. The Corpus Callosum Wallerian Degeneration in the Unilateral Brain Tumors: Evaluation with Diffusion Tensor Imaging (DTI). J Clin Diagn Res 2013; 7:320-5. [PMID: 23543618 DOI: 10.7860/jcdr/2013/4491.2757] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Accepted: 09/19/2012] [Indexed: 11/24/2022]
Abstract
PURPOSE The purpose of this study was to evaluate whether DTI could demonstrate the water diffusivity changes in the corpus callosum (CC), which were not visible on the morphologic imaging in patients with glioblastoma multiforme (GBM) and brain metastases with no midline CC infiltration. MATERIALS AND METHODS Twenty-seven patients with treatment naïve unilateral GBM and eleven patients with a solitary brain metastasis with no midline CC infiltration underwent DTI. Ten controls with normal brain MRI were also included. Based on the tensors, the principal diffusion directions, the anisotropy values, and the prior information about the diffusivity pattern in CC, a similarity measure was proposed. Subsequently, the CC was automatically divided into the Witelson subdivisions. RESULTS We observed significantly decreased fractional anisotropy values in all the regions of CC in the patients with GBM and metastases as compared to those in the controls. The mean diffusivity values showed a significant increase in all the regions of CC, except the splenium in patients with GBM and the isthmus in the patients with metastases, as compared to that in the controls respectively. CONCLUSION In conclusion, DTI is more sensitive than the morphologic MR imaging in the evaluation of changes within the CC, in brain tumours which do not infiltrate the CC. However, these changes of the DTI metrics in the CC are due to a Wallerian degeneration rather than a tumour infiltration, as was shown by our results, as similar changes were seen in the GBM as well as the non-infiltrating metastases patients.
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Affiliation(s)
- Sona Saksena
- Division of Neuroradiology, Department of Radiology, Henry Ford Health System , Detroit, MI 48202, USA
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Kim H, Harrison A, Kankirawatana P, Rozzelle C, Blount J, Torgerson C, Knowlton R. Major white matter fiber changes in medically intractable neocortical epilepsy in children: A diffusion tensor imaging study. Epilepsy Res 2013; 103:211-20. [PMID: 22917916 DOI: 10.1016/j.eplepsyres.2012.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/25/2012] [Accepted: 07/30/2012] [Indexed: 11/25/2022]
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Liu M, Concha L, Lebel C, Beaulieu C, Gross DW. Mesial temporal sclerosis is linked with more widespread white matter changes in temporal lobe epilepsy. NEUROIMAGE-CLINICAL 2012; 1:99-105. [PMID: 24179742 PMCID: PMC3757721 DOI: 10.1016/j.nicl.2012.09.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/19/2012] [Accepted: 09/22/2012] [Indexed: 12/04/2022]
Abstract
Temporal lobe epilepsy patients with unilateral mesial temporal sclerosis (TLE + uMTS) have been demonstrated to have extensive white matter abnormalities both ipsilateral and contralateral to the seizure onset zone. However, comparatively less is known about the white matter integrity of TLE patients without MTS (non-lesional TLE, nl-TLE). The purpose of the study was to investigate the diffusion properties of thirteen major white matter tracts in patients with TLE + uMTS and nl-TLE. Diffusion tensor imaging (DTI) was performed on 23 TLE + uMTS (15 left MTS and 8 right MTS), 15 nl-TLE and 21 controls. Thirteen tracts were delineated by tractography and their diffusion parameters compared for the two TLE groups relative to controls, with left and right hemispheres combined per tract. A subgroup analysis investigated left and right MTS separately. Compared to controls, reduced anisotropy was detected in ten tracts for TLE + uMTS, but only the parahippocampal cingulum and tapetum for nl-TLE. Right MTS subgroup showed reduced anisotropy in 7 tracts bilaterally (3 limbic, 3 association, 1 projection) and 2 tracts ipsilaterally (1 association, 1 projection) and the body of the corpus callosum whereas the left MTS subgroup showed reduced anisotropy in 4 tracts bilaterally (2 limbic, 1 association, 1 projection) and 2 tracts ipsilaterally (1 limbic, 1 association). Diffusion abnormalities in tracts were observed within and beyond the temporal lobe in TLE + uMTS and were more widespread than in nl-TLE. Patients with right MTS had more extensive, bilateral abnormalities in comparison to left MTS. These findings suggest different dysfunctional networks in TLE patients with and without MTS.
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Affiliation(s)
- Min Liu
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Quantitative brain diffusion-tensor MRI findings in patients with sickle cell disease. AJR Am J Roentgenol 2012; 198:1167-74. [PMID: 22528909 DOI: 10.2214/ajr.11.7404] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the microstructure of various regions of the brain using diffusion-tensor imaging (DTI) in patients with sickle cell disease (SCD) and in age- and sex-matched healthy control subjects. We also investigated the fiber tractography findings of the corpus callosum (CC) and corticospinal tracts (CSTs). SUBJECTS AND METHODS Sixteen right-handed patients with SCD and 14 age- and sex-matched right-handed healthy control subjects were scanned using conventional MR sequences and DTI. Fractional anisotropy (FA) and apparent diffusion coefficients (ADCs) were calculated and regions of interest were selected in various brain areas (superior and inferior frontal, parietal, occipital, and temporal white matter areas), anterior and posterior periventricular areas, centrum semiovale, basal ganglia (lentiform nucleus, head of caudate nucleus), thalamus, cerebral peduncles, pons, cerebellar white matter areas, and CC. Diffusion-tensor tractography of the CC and CSTs was also performed. RESULTS For the patients with SCD, significantly reduced FA values, increased ADC values, or both were seen clustered in several brain areas, including the CC, frontal white matter, centrum semiovale, periventricular areas, head of the caudate nucleus, thalamus, brainstem, and pons (p < 0.05). Statistically significant reductions in fiber counts in the first and fifth segments of the CC and in CSTs bilaterally were also observed in patients with SCD (p < 0.05). CONCLUSION DTI shows microstructural abnormalities of various brain areas in patients with SCD.
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Qin W, Zhang M, Piao Y, Guo D, Zhu Z, Tian X, Li K, Yu C. Wallerian degeneration in central nervous system: dynamic associations between diffusion indices and their underlying pathology. PLoS One 2012; 7:e41441. [PMID: 22829950 PMCID: PMC3400645 DOI: 10.1371/journal.pone.0041441] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/21/2012] [Indexed: 11/24/2022] Open
Abstract
Background Although diffusion tensor imaging has been used to monitor Wallerian degeneration, the exact relationship between the evolution of diffusion indices and its underlying pathology, especially in central nervous system, remains largely unknown. Here we aimed to address this question using a cat Wallerian degeneration model of corticospinal tract. Methodology/Principal Findings Twenty-five domestic mature Felis catus were included in the present study. The evolution of diffusion indices, including mean diffusivity (MD), fractional anisotropy (FA), primary (λ1) and transverse eigenvalues (λ23) of the degenerated corticospinal tract, were observed at baseline (before modeling) and at 2, 4, 6, 8, 10, 15, 20, 25, 30, 45 and 60 days after modeling in 4 cats. Pathological examinations were performed at eight time points mentioned above. Wallerian degeneration can be detected as early as the 2nd day after modeling by both diffusion tensor imaging and pathology. According to the evolution of diffusion indices, Wallerian degeneration can be classified into 2 stages. During the early stage (within 8 days after modeling), progressive disintegration of axons and myelin sheaths underlies the decreases in FA and λ1 and the increase in λ23. However, during the late stage (after 8 days), the gradual increases in FA, MD and λ1 and the unchanged λ23 seem to be a comprehensive reflection of the pathological processes including microglia activation, myelin clearance, and astrocytosis. Conclusions/Significance Our findings help the understanding of the altered diffusion indices in the context of pathology and suggest that diffusion tensor imaging has the potential to monitor the processes of Wallerian degeneration in the central nervous system in vivo after acute damage.
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Affiliation(s)
- Wen Qin
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Min Zhang
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Deyu Guo
- Department of Experimental Animal, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zixin Zhu
- Department of Experimental Animal, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xin Tian
- Department of Experimental Animal, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- * E-mail: (KL); (CY)
| | - Chunshui Yu
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- * E-mail: (KL); (CY)
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Di Paola M, Luders E, Cherubini A, Sanchez-Castaneda C, Thompson PM, Toga AW, Caltagirone C, Orobello S, Elifani F, Squitieri F, Sabatini U. Multimodal MRI analysis of the corpus callosum reveals white matter differences in presymptomatic and early Huntington's disease. Cereb Cortex 2012; 22:2858-66. [PMID: 22223853 DOI: 10.1093/cercor/bhr360] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent magnetic resonance imaging (MRI) studies suggest that abnormalities in Huntington's disease (HD) extend to white matter (WM) tracts in early HD and even in presymptomatic stages. Thus, changes of the corpus callosum (CC) may reflect various aspects of HD pathogenesis. We recruited 17 HD patients, 17 pre-HD subjects, and 34 healthy age-matched controls. Three-dimensional anatomical MRI and diffusion tensor images of the brain were acquired on a 3T scanner. Combining region-of-interest analyses, voxel-based morphometry, and tract-based spatial statistics, we investigated callosal thickness, WM density, fractional anisotropy, and radial and axial diffusivities. Compared with controls, pre-HD subjects showed reductions of the isthmus, likely due to myelin damage. Compared with pre-HD subjects, HD patients showed reductions of isthmus and body, with axonal damage confined to the body. Compared with controls, HD patients had significantly decreased callosal measures in extended regions across almost the entire CC. At this disease stage, both myelin and axonal damage are detectable. Supplementary multiple regression analyses revealed that WM reduction density in the isthmus as well as Disease Burden scores allowed to predict the "HD development" index. While callosal changes seem to proceed in a posterior-to-anterior direction as the diseases progresses, this observation requires validation in future longitudinal investigations.
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Affiliation(s)
- M Di Paola
- Laboratory of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy.
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Liu M, Concha L, Beaulieu C, Gross DW. Distinct white matter abnormalities in different idiopathic generalized epilepsy syndromes. Epilepsia 2011; 52:2267-75. [PMID: 22092238 DOI: 10.1111/j.1528-1167.2011.03313.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
PURPOSE By definition idiopathic generalized epilepsy (IGE) is not associated with structural abnormalities on conventional magnetic resonance imaging (MRI). However, recent quantitative studies suggest white and gray matter alterations in IGE. The purpose of this study was to investigate whether there are white and/or gray matter structural differences between controls and two subsets of IGE, namely juvenile myoclonic epilepsy (JME) and IGE with generalized tonic-clonic seizures only (IGE-GTC). METHODS We assessed white matter integrity and gray matter volume using diffusion tensor tractography-based analysis of fractional anisotropy and voxel-based morphometry, respectively, in 25 patients with IGE, all of whom had experienced generalized tonic-clonic convulsions. Specifically, 15 patients with JME and 10 patients with IGE-GTC were compared to two groups of similarly matched controls separately. Correlations between total lifetime generalized tonic-clonic seizures and fractional anisotropy were investigated for both groups. KEY FINDINGS Tractography revealed lower fractional anisotropy in specific tracts including the crus of the fornix, body of corpus callosum, uncinate fasciculi, superior longitudinal fasciculi, anterior limb of internal capsule, and corticospinal tracts in JME with respect to controls, whereas there were no fractional anisotropy differences in IGE-GTC. No correlation was found between fractional anisotropy and total lifetime generalized tonic-clonic seizures for either JME or IGE-GTC. Although false discovery rate-corrected voxel-based morphometry (VBM) showed no gray matter volume differences between patient and control groups, spatial extent cluster-corrected VBM analysis suggested a trend of gray matter volume reduction in frontal and central regions in both patient groups, more lateral in JME and more medial in IGE-GTC. SIGNIFICANCE The findings support the idea that the clinical syndromes of JME and IGE-GTC have unique anatomic substrates. The fact that the primary clinical difference between JME and IGE-GTC is the occurrence of myoclonus in the former raises the possibility that disruption of white matter integrity may be the underlying mechanism responsible for myoclonus in JME. The cross-sectional study design and relatively small number of subjects limits the conclusions that can be drawn here; however, the absence of a correlation between fractional anisotropy and lifetime seizures is suggestive that the white matter abnormalities observed in JME may not be secondary to seizures.
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Affiliation(s)
- Min Liu
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Günbey H, Ercan K, FindikoğLu A, Bilir E, Karaoglanoglu M, Komurcu F, Alhan A. Secondary Corpus Callosum Abnormalities Associated with Antiepileptic Drugs in Temporal Lobe Epilepsy. Neuroradiol J 2011; 24:316-23. [DOI: 10.1177/197140091102400223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 03/04/2011] [Indexed: 11/16/2022] Open
Abstract
Epilepsy is more than a grey-matter disorder affecting large white matter connections of the brain with seizure generation and propagation. The mechanism for such changes remains unclear. The purpose of this study was to investigate the microstructural changes in the corpus callosum in temporal lobe epilepsy (TLE) patients and whether these abnormalities are related to antiepileptic drug (AED) therapy. Ten TLE patients receiving AED therapy, ten TLE patients with no therapy and ten controls were included in the study. The regions of interest in the corpus callosum were outlined to each Witelson region (WR). Fractional anisotrophy (FA), apparent diffusion coefficient (ADC), three main diffusivity values (λ1, λ2, λ3) and tractography were acquired from each WR. DTI indices of these tracts and each WR were compared between the three subject groups and correlates examined with clinical variables that included duration of epilepsy, gender, AED type and AED therapy exposure. In TLE subjects with receiving AED therapy significantly (p<0.05) decreased FA and increased ADC values of corpus callosum were obtained when compared to the other groups. There was no significant relationship between AED type and DTI indices. Analysis of eigen values in the splenium of corpus callosum (WR7) showed λ1 values were significantly decreased in relation to AED medication duration (p<0.05). FA values of rostrum and corpus showed a reduction with duration of epilepsy. TLE is associated with abnormal integrity of corpus callosum white matter tracts. AED therapy may cause additional damage on secondary degeneration and medication time effects especially on the splenium of corpus callosum.
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Affiliation(s)
- H.P. Günbey
- Department of Radiology, Kecioren Education and Research Hospital; Ankara, Turkey
| | - K. Ercan
- Department of Radiology; Ankara, Turkey
| | - A.S. FindikoğLu
- Department of Radiology, Erzincan Hospital; Erzincan, Turkey
| | - E. Bilir
- Department of Neurology, Gazi University; Ankara, Turkey
| | | | - F. Komurcu
- Department of Neurology, Atatürk Education and Research Hospital; Ankara, Turkey
| | - A. Alhan
- Department of Statistics, Ufuk University; Ankara, Turkey
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O'Dwyer R, Wehner T, LaPresto E, Ping L, Tkach J, Noachtar S, Diehl B. Differences in corpus callosum volume and diffusivity between temporal and frontal lobe epilepsy. Epilepsy Behav 2010; 19:376-82. [PMID: 20920892 DOI: 10.1016/j.yebeh.2010.06.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 06/23/2010] [Accepted: 06/24/2010] [Indexed: 11/26/2022]
Abstract
We analyzed volume and diffusivity measures of the corpus callosum (CC) in patients with temporal (TLE) and frontal (FLE) lobe epilepsy in comparison with healthy subjects. On high-resolution T1-weighted scans of 18 controls and 44 patients the volumes (cm(3)) of Witelson regions (WRs) and the entire CC were measured. The apparent diffusion coefficients (ADCs, 10(-5)mm(2)s(-1)) for the entire CC and three areas of interest were measured from co-registered ADC maps. The CC of patients with TLE and FLE, corrected for total brain volume, was smaller than that of controls. Patients' ADC values were higher than those of controls. Findings were significant for WR1, WR2, and WR6, the CC regions connecting the frontal and temporal lobes. Patients with FLE had smaller WR1 and higher ADC values; in patients with TLE, the findings were similar for WR6. Atrophy and increased diffusivity in subregions of the CC connecting homotopic contralateral cortical regions indicate anatomical abnormalities extending beyond the epileptogenic zone in FLE and TLE.
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Affiliation(s)
- R O'Dwyer
- Neurological Institute, Epilepsy Center, Cleveland Clinic, Cleveland, OH 44195, USA.
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Meng L, Xiang J, Kotecha R, Rose D, Zhao H, Zhao D, Yang J, Degrauw T. White matter abnormalities in children and adolescents with temporal lobe epilepsy. Magn Reson Imaging 2010; 28:1290-8. [DOI: 10.1016/j.mri.2010.03.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 02/21/2010] [Accepted: 03/11/2010] [Indexed: 11/29/2022]
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McDonald CR, Hagler DJ, Girard HM, Pung C, Ahmadi ME, Holland D, Patel RH, Barba D, Tecoma ES, Iragui VJ, Halgren E, Dale AM. Changes in fiber tract integrity and visual fields after anterior temporal lobectomy. Neurology 2010; 75:1631-8. [PMID: 20881271 DOI: 10.1212/wnl.0b013e3181fb44db] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE To investigate postoperative changes in fiber tract integrity in patients with temporal lobe epilepsy (TLE) following anterior temporal lobectomy (ATL) and to determine whether postoperative changes are 1) stable vs progressive and 2) related to visual field defects. METHODS Diffusion tensor imaging (DTI) was obtained in 7 patients with TLE before, 2 months after, and 1 year after ATL. Changes in fractional anisotropy (FA) were evaluated in a whole-brain voxel-wise analysis, as well within specific fiber tracts. Repeated-measures analysis of variance was performed to examine the time course of FA changes within ipsilateral and contralateral fiber tracts. Quantitative visual field analysis was performed to determine whether decreases in regional FA were related to the extent or location of visual field defects. RESULTS Patients showed decreased FA 2 months post-ATL in ipsilateral fiber tracts transected during surgery (parahippocampal cingulum, uncinate fasciculus, inferior longitudinal fasciculus, and fornix), as well as in fiber tracts not directly transected (inferior fronto-occipital fasciculus and corpus callosum). Additional decreases in FA were not observed from 2 months to 1 year post-ATL. Visual field defects in most patients were characterized by incomplete quadrantanopsias. However, FA reductions in one patient extended into temporo-occipital cortex and the splenium of the corpus callosum and were associated with a complete hemianopia. CONCLUSIONS Wallerian degeneration is apparent 2 months following unilateral ATLs in ipsilateral fibers directly and indirectly affected during surgery. These changes do not appear to progress over the course of a year, but may correlate with the nature and extent of postoperative visual field defects.
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Affiliation(s)
- C R McDonald
- Department of Psychiatry, Multimodal Imaging Laboratory, University of California-San Diego, 8950 Villa La Jolla Drive, La Jolla, CA 92037, USA.
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White matter is altered with parental family history of Alzheimer's disease. Alzheimers Dement 2010; 6:394-403. [PMID: 20713315 DOI: 10.1016/j.jalz.2009.11.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 10/23/2009] [Accepted: 11/16/2009] [Indexed: 11/21/2022]
Abstract
BACKGROUND Brain alterations in structure and function have been identified in people with risk factors for sporadic type Alzheimer's disease (AD), suggesting that alterations can be detected decades before AD diagnosis. Although the effect of apolipoprotein E (APOE) varepsilon4 on the brain is well-studied, less is known about the effect of family history of AD. We examined the main effects of family history and APOE varepsilon4 on brain integrity, in addition to assessing possible additive effects of these two risk factors. METHODS Diffusion tensor imaging was performed in 136 middle-aged asymptomatic participants stratified on family history and APOE varepsilon4. Mean diffusivity and fractional anisotropy (FA) were entered in factorial analyses to test the effect of AD risk on microstructural brain integrity. We performed a post hoc analysis of the three principal diffusivities (lambda1, lambda2, lambda3) to provide potential additional insight on underlying tissue differences. RESULTS Parental family history of AD was associated with lower FA in regions of the brain known to be affected by AD, including cingulum, corpus callosum, tapetum, uncinate fasciculus, hippocampus, and adjacent white matter. Contrary to previous reports, there was no main effect of APOE varepsilon4; however, there was an additive effect of family history and APOE varepsilon4 in which family history-positive participants who were also APOE varepsilon4 carriers had the lowest FA compared with the other groups. CONCLUSIONS The data indicate that unknown risk factors contained in family history are associated with changes in microstructural brain integrity in areas of the brain known to be affected by AD. Importantly, the results provide further evidence that AD pathology might be detected before cognitive changes, perhaps decades before disease onset.
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Parekh MB, Carney PR, Sepulveda H, Norman W, King M, Mareci TH. Early MR diffusion and relaxation changes in the parahippocampal gyrus precede the onset of spontaneous seizures in an animal model of chronic limbic epilepsy. Exp Neurol 2010; 224:258-70. [PMID: 20394745 DOI: 10.1016/j.expneurol.2010.03.031] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/15/2010] [Accepted: 03/30/2010] [Indexed: 10/19/2022]
Abstract
Structural changes in limbic regions are often observed in individuals with temporal lobe epilepsy (TLE) and in animal models. However, the brain structural changes during the evolution into epilepsy remain largely unknown. Therefore, the purpose of this study was to define the temporal changes in limbic structures after experimental status epilepticus (SE) during the latency period of epileptogenesis in vivo, with quantitative diffusion tensor imaging (DTI) and T2 relaxometry in an animal model of chronic TLE. A pair of fifty micron electrodes was implanted into the ventral hippocampus in twelve male adult rats. Self-sustaining SE was induced with electrical stimulation in eleven rats. Three rats served as age-matched controls. In vivo diffusion tensor and T2 magnetic resonance imaging (MRI) was performed at 11.1 Tesla, pre- and post-implantation of electrodes and 3, 5, 7, 10, 20, 40 and 60 days post-SE to assess structural changes. Spontaneous seizures were identified with continuous time-locked video-monitoring. Following imaging in vivo, fixed, excised brains were MR imaged at 17.6 Tesla. Subsequently, histological analysis was correlated with MRI results. Following SE, 8/11 injured rats developed spontaneous seizures. Unique to these 8 rats, early T2, diffusivity and anisotropy changes were observed in vivo within the parahippocampal gyrus (contralateral) and fimbria (bilateral). In excised brains, bilateral increase in anisotropy was observed in the dentate gyrus, corresponding to mossy fiber sprouting as determined by Timm staining. Using T2 relaxometry and DTI, specific transient and long-term structural changes were observed only in rats that developed spontaneous limbic seizures.
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Affiliation(s)
- Mansi B Parekh
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
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Hutchinson E, Pulsipher D, Dabbs K, Myers y Gutierrez A, Sheth R, Jones J, Seidenberg M, Meyerand E, Hermann B. Children with new-onset epilepsy exhibit diffusion abnormalities in cerebral white matter in the absence of volumetric differences. Epilepsy Res 2009; 88:208-14. [PMID: 20044239 DOI: 10.1016/j.eplepsyres.2009.11.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 11/17/2022]
Abstract
The purpose of this investigation was to examine the diffusion properties of cerebral white matter in children with recent onset epilepsy (n=19) compared to healthy controls (n=11). Subjects underwent DTI with quantification of mean diffusion (MD), fractional anisotropy (FA), axial diffusivity (D(ax)) and radial diffusivity (D(rad)) for regions of interest including anterior and posterior corpus callosum, fornix, cingulum, and internal and external capsules. Quantitative volumetrics were also performed for the corpus callosum and its subregions (anterior, midbody and posterior) and total lobar white and gray matter for the frontal, parietal, temporal and occipital lobes. The results demonstrated no group differences in total lobar gray or white matter volumes or volume of the corpus callosum and its subregions, but did show reduced FA and increased D(rad) in the posterior corpus callosum and cingulum. These results provide the earliest indication of microstructural abnormality in cerebral white matter among children with idiopathic epilepsies. This abnormality occurs in the context of normal volumetrics and suggests disruption in myelination processes.
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Affiliation(s)
- Elizabeth Hutchinson
- Neuroscience Training Program, University of Wisconsin, 7225 Medical Sciences Center, Madison, WI 53706, USA.
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Schoene-Bake JC, Faber J, Trautner P, Kaaden S, Tittgemeyer M, Elger CE, Weber B. Widespread affections of large fiber tracts in postoperative temporal lobe epilepsy. Neuroimage 2009; 46:569-76. [DOI: 10.1016/j.neuroimage.2009.03.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 03/04/2009] [Accepted: 03/05/2009] [Indexed: 11/25/2022] Open
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