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Ai H, Yang C, Lu M, Ren J, Li Z, Zhang Y. Abnormal white matter structural network topological property in patients with temporal lobe epilepsy. CNS Neurosci Ther 2024; 30:e14414. [PMID: 37622409 PMCID: PMC10805448 DOI: 10.1111/cns.14414] [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: 02/13/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND Diffusion tensor imaging (DTI) studies have demonstrated white matter (WM) abnormalities in patients with temporal lobe epilepsy (TLE). However, alterations in the topological properties of the WM structural network in patients with TLE remain unclear. Graph theoretical analysis provides a new perspective for evaluating the connectivity of WM structural networks. METHODS DTI was used to map the structural networks of 18 patients with TLE (10 males and 8 females) and 29 (17 males and 12 females) age- and gender-matched normal controls (NC). Graph theory was used to analyze the whole-brain networks and their topological properties between the two groups. Finally, partial correlation analyses were performed on the weighted network properties and clinical characteristics, namely, duration of epilepsy, verbal intelligence quotient (IQ), and performance IQ. RESULTS Patients with TLE exhibited reduced global efficiency and increased characteristic path length. A total of 31 regions with nodal efficiency alterations were detected in the fractional anisotropy_ weighted network of the patients. Communication hubs, such as the middle temporal gyrus, right inferior temporal gyrus, left calcarine, and right superior parietal gyrus, were also differently distributed in the patients compared with the NC. Several node regions showed close relationships with duration of epilepsy, verbal IQ, and performance IQ. CONCLUSIONS Our results demonstrate the disruption of the WM structural network in TLE patients. This study may contribute to the further understanding of the pathological mechanism of TLE.
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Affiliation(s)
- Haiming Ai
- Faculty of Science and TechnologyBeijing Open UniversityBeijingChina
| | - Chunlan Yang
- College of Life Science and BioengineeringBeijing University of TechnologyBeijingChina
| | - Min Lu
- College of Life Science and BioengineeringBeijing University of TechnologyBeijingChina
| | - Jiechuan Ren
- Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Zhimei Li
- Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Yining Zhang
- Department of EquipmentBaoding first Central HospitalBaodingChina
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2
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De Benedictis A, Rossi-Espagnet MC, de Palma L, Sarubbo S, Marras CE. Structural networking of the developing brain: from maturation to neurosurgical implications. Front Neuroanat 2023; 17:1242757. [PMID: 38099209 PMCID: PMC10719860 DOI: 10.3389/fnana.2023.1242757] [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: 06/19/2023] [Accepted: 11/09/2023] [Indexed: 12/17/2023] Open
Abstract
Modern neuroscience agrees that neurological processing emerges from the multimodal interaction among multiple cortical and subcortical neuronal hubs, connected at short and long distance by white matter, to form a largely integrated and dynamic network, called the brain "connectome." The final architecture of these circuits results from a complex, continuous, and highly protracted development process of several axonal pathways that constitute the anatomical substrate of neuronal interactions. Awareness of the network organization of the central nervous system is crucial not only to understand the basis of children's neurological development, but also it may be of special interest to improve the quality of neurosurgical treatments of many pediatric diseases. Although there are a flourishing number of neuroimaging studies of the connectome, a comprehensive vision linking this research to neurosurgical practice is still lacking in the current pediatric literature. The goal of this review is to contribute to bridging this gap. In the first part, we summarize the main current knowledge concerning brain network maturation and its involvement in different aspects of normal neurocognitive development as well as in the pathophysiology of specific diseases. The final section is devoted to identifying possible implications of this knowledge in the neurosurgical field, especially in epilepsy and tumor surgery, and to discuss promising perspectives for future investigations.
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Affiliation(s)
| | | | - Luca de Palma
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Silvio Sarubbo
- Department of Neurosurgery, Santa Chiara Hospital, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
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Doyen M, Chawki MB, Heyer S, Guedj E, Roch V, Marie PY, Tyvaert L, Maillard L, Verger A. Metabolic connectivity is associated with seizure outcome in surgically treated temporal lobe epilepsies: A 18F-FDG PET seed correlation analysis. Neuroimage Clin 2022; 36:103210. [PMID: 36208546 PMCID: PMC9668618 DOI: 10.1016/j.nicl.2022.103210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 12/14/2022]
Abstract
18F-FDG PET provides high sensitivity for the pre-surgical assessment of drug-resistant temporal lobe epilepsy (TLE). However, little is known about the metabolic connectivity of epileptogenic networks involved. This study therefore aimed to evaluate the association between metabolic connectivity and seizure outcome in surgically treated TLE. METHODS The study included 107 right-handed patients that had undergone a presurgical interictal 18F-FDG PET assessment followed by an anterior temporal lobectomy and were classified according to seizure outcome 2 years after surgery. Metabolic connectivity was evaluated by seed correlation analysis in left and right epilepsy patients with a Class Engel IA or > IA outcome and compared to age-, sex- and handedness-matched healthy controls. RESULTS Increased metabolic connectivity was observed in the >IA compared to the IA group within the operated temporal lobe (respective clusters of 7.5 vs 3.3 cm3 and 2.6 cm3 vs 2.2 cm3 in left and right TLE), and to a lower extent with the contralateral temporal lobe (1.2 vs 0.7 cm3 and 1.7 cm3 vs 0.7 cm3 in left and right TLE). Seed correlations provided added value for the estimated individual performance of seizure outcome over the group comparisons in left TLE (AUC of 0.74 vs 0.67). CONCLUSION Metabolic connectivity is associated with outcome in surgically treated TLE with a strengthened epileptogenic connectome in patients with non-free-seizure outcomes. The added value of seed correlation analysis in left TLE underlines the importance of evaluating metabolic connectivity in network related diseases.
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Affiliation(s)
- Matthieu Doyen
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France,Université de Lorraine, IADI, INSERM U1254, F-54000 Nancy, France,Corresponding author at: Université de Lorraine, IADI - INSERM U1254, Department of Nuclear Medicine and Nancyclotep Imaging Platform, F-54000 Nancy, France.
| | - Mohammad B. Chawki
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France
| | - Sébastien Heyer
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France
| | - Eric Guedj
- Aix Marseille Univ, APHM, CNRS, Centrale Marseille, Institut Fresnel, Timone Hospital, CERIMED, Nuclear Medicine Department, F-13000 Marseille, France
| | - Véronique Roch
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France
| | - Pierre-Yves Marie
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France,Université de Lorraine, INSERM, DCAC, Nancy, France
| | - Louise Tyvaert
- Université de Lorraine, CRAN UMR 7039, Nancy, France,Department of Neurology, CHRU Nancy, National Reference Center for Rare Epilepsies, F-54000 Nancy, France
| | - Louis Maillard
- Université de Lorraine, CRAN UMR 7039, Nancy, France,Department of Neurology, CHRU Nancy, National Reference Center for Rare Epilepsies, F-54000 Nancy, France
| | - Antoine Verger
- Université de Lorraine, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, F-54000 Nancy, France,Université de Lorraine, IADI, INSERM U1254, F-54000 Nancy, France
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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: 2] [Impact Index Per Article: 0.7] [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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5
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Leon-Rojas J, Cornell I, Rojas-Garcia A, D’Arco F, Panovska-Griffiths J, Cross H, Bisdas S. The role of preoperative diffusion tensor imaging in predicting and improving functional outcome in pediatric patients undergoing epilepsy surgery: a systematic review. BJR Open 2021; 3:20200002. [PMID: 34381942 PMCID: PMC8320117 DOI: 10.1259/bjro.20200002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Diffusion tensor imaging (DTI) is a useful neuroimaging technique for surgical planning in adult patients. However, no systematic review has been conducted to determine its utility for pre-operative analysis and planning of Pediatric Epilepsy surgery. We sought to determine the benefit of pre-operative DTI in predicting and improving neurological functional outcome after epilepsy surgery in children with intractable epilepsy. METHODS A systematic review of articles in English using PubMed, EMBASE and Scopus databases, from inception to January 10, 2020 was conducted. All studies that used DTI as either predictor or direct influencer of functional neurological outcome (motor, sensory, language and/or visual) in pediatric epilepsy surgical candidates were included. Data extraction was performed by two blinded reviewers. Risk of bias of each study was determined using the QUADAS 2 Scoring System. RESULTS 13 studies were included (6 case reports/series, 5 retrospective cohorts, and 2 prospective cohorts) with a total of 229 patients. Seven studies reported motor outcome; three reported motor outcome prediction with a sensitivity and specificity ranging from 80 to 85.7 and 69.6 to 100%, respectively; four studies reported visual outcome. In general, the use of DTI was associated with a high degree of favorable neurological outcomes after epilepsy surgery. CONCLUSION Multiple studies show that DTI helps to create a tailored plan that results in improved functional outcome. However, more studies are required in order to fully assess its utility in pediatric patients. This is a desirable field of study because DTI offers a non-invasive technique more suitable for children. ADVANCES IN KNOWLEDGE This systematic review analyses, exclusively, studies of pediatric patients with drug-resistant epilepsy and provides an update of the evidence regarding the role of DTI, as part of the pre-operative armamentarium, in improving post-surgical neurological sequels and its potential for outcome prediction.
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Affiliation(s)
| | - Isabel Cornell
- Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London, UK
| | | | - Felice D’Arco
- Department of Pediatric Neuroradiology, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | | | - Helen Cross
- Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London, UK
- NeurALL Research Group, Universidad Internacional del Ecuador, Medical School, Quito, Ecuador
- Department of Applied Health Research, University College London, London, UK
- Department of Pediatric Neuroradiology, Great Ormond Street Hospital for Children NHS Trust, London, UK
- Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, UK
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6
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Abnormalities in the thalamo-cortical network in patients with functional constipation. Brain Imaging Behav 2021; 15:630-642. [PMID: 32314199 DOI: 10.1007/s11682-020-00273-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Functional constipation (FCon) is a common functional gastrointestinal disorder (FGID); neuroimaging studies have shown brain functional abnormalities in thalamo-cortical regions in patients with FGID. However, association between FCon and topological characteristics of brain networks remains largely unknown. We employed resting-state functional magnetic resonance imaging (RS-fMRI) and graph theory approach to investigate functional brain topological organization in 42 patients with FCon and 41 healthy controls (HC) from perspectives of global, regional and modular levels. Results showed patients with FCon had a significantly lower normalized clustering coefficient and small-worldness, implying decreased brain functional connectivity. Regions showed altered nodal degree and efficiency mainly located in the thalamus, rostral anterior cingulate cortex (rACC), and supplementary motor area (SMA), which are involved in somatic/sensory, emotional processing and motor-control. For the modular analysis, thalamus, rACC and SMA had an aberrant within-module nodal degree and nodal efficiency, and thalamus-related network exhibited abnormal interaction with the limbic network (amygdala and hippocampal gyrus). Nodal degree in the thalamus was negatively correlated with difficulty of defecation, and nodal degree in the rACC was negatively correlated with sensation of incomplete evacuation. These findings indicated that FCon was associated with abnormalities in the thalamo-cortical network.
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Sun H, Ma L, Zhang Y, Pan X, Wang C, Zhang J, Zhang X, Sun H, Wang Q, Zhu W. A Purinergic P2 Receptor Family-Mediated Increase in Thrombospondin-1 Bolsters Synaptic Density and Epileptic Seizure Activity in the Amygdala-Kindling Rat Model. Front Cell Neurosci 2018; 12:302. [PMID: 30386206 PMCID: PMC6199899 DOI: 10.3389/fncel.2018.00302] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/20/2018] [Indexed: 01/08/2023] Open
Abstract
Previous studies suggested that the thrombospondin-1/transforming growth factor-β1 (TSP-1/TGF-β1) pathway might be critical in synaptogenesis during development and that the purinergic P2 receptor family could regulate synaptogenesis by modulating TSP-1 signaling. However, it is unclear whether this pathway plays a role in synaptogenesis during epileptic progression. This study was designed to investigate this question by analyzing the dynamic changes and effects of TSP-1 levels on the density of synaptic markers that are related to epileptic seizure activity. In addition, we evaluated whether P2-type receptors could regulate these effects. We generated a rat seizure model via amygdala kindling and inhibited TSP-1 activity using small interfering RNA (siRNA) interference and pharmacological inhibition. We treated the rats with antagonists of P2 or P2Y receptors, pyridoxalphosphate-6-azophenyl-2’,4’-disulfonic (PPADS) or Reactive Blue 2. Following this, we quantified TSP-1 and TGF-β1 immunoreactivity (IR), the density of synaptic markers, and seizure activity. There were significantly more synapses/excitatory synapses in several brain regions, such as the hippocampus, which were associated with progressing epileptic discharges after kindling. These were associated with increased TSP-1 and TGF-β1-IR. Genetic or pharmacologic inhibition of TSP-1 significantly reduced the density of synaptic/excitatory synaptic markers and inhibited the generalization of focal epilepsy. The administration of PPADS or Reactive Blue 2 attenuated the increase in TSP-1-IR and the increase in the density of synaptic markers that follows kindling and abolished most of the epileptic seizure activity. Altogether, our results indicate that the TSP-1/TGF-β1 pathway and its regulation by P2, particularly P2Y-type receptors, may be a critical promoter of synaptogenesis during the progression of epilepsy. Therefore, components of this pathway may be targets for novel antiepileptic drug development.
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Affiliation(s)
- Hongliu Sun
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Luyu Ma
- Shandong Academy of Medical Sciences (SDAMS) Jinan, China
| | - Yurong Zhang
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Xiaohong Pan
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Chaoyun Wang
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Jinjin Zhang
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Xiuli Zhang
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Hongwei Sun
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Qiaoyun Wang
- School of Pharmaceutical Sciences, Binzhou Medical University Yantai, China
| | - Wei Zhu
- Shandong Academy of Medical Sciences (SDAMS) Jinan, China
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Chen LT, Fan XL, Li HJ, Ye CL, Yu HH, Xin HZ, Gong HH, Peng DC, Yan LP. Aberrant brain functional connectome in patients with obstructive sleep apnea. Neuropsychiatr Dis Treat 2018; 14:1059-1070. [PMID: 29713176 PMCID: PMC5912371 DOI: 10.2147/ndt.s161085] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Obstructive sleep apnea (OSA) is accompanied by widespread abnormal spontaneous regional activity related to cognitive deficits. However, little is known about the topological properties of the functional brain connectome of patients with OSA. This study aimed to use the graph theory approaches to investigate the topological properties and functional connectivity (FC) of the functional connectome in patients with OSA, based on resting-state functional magnetic resonance imaging (rs-fMRI). METHODS Forty-five male patients with newly diagnosed untreated severe OSA and 45 male good sleepers (GSs) underwent a polysomnography (PSG), clinical evaluations, and rs-fMRI scans. The automated anatomical labeling (AAL) atlas was used to construct the functional brain connectome. The topological organization and FC of brain functional networks in patients with OSA were characterized using graph theory methods and investigated the relationship between functional network topology and clinical variables. RESULTS Both the patients with OSA and the GSs exhibited high-efficiency "small-world" network attributes. However, the patients with OSA exhibited decreased σ, γ, Eglob; increased Lp, λ; and abnormal nodal centralities in several default-mode network (DMN), salience network (SN), and central executive network (CEN) regions. However, the patients with OSA exhibited abnormal functional connections between the DMN, SN, and CEN. The disrupted FC was significantly positive correlations with the global network metrics γ and σ. The global network metrics were significantly correlated with the Epworth Sleepiness Scale (ESS) score, Montreal Cognitive Assessment (MoCA) score, and oxygen desaturation index. CONCLUSION The findings suggest that the functional connectome of patients with OSA exhibited disrupted functional integration and segregation, and functional disconnections of the DMN, SN, and CEN. The aberrant topological attributes may be associated with disrupted FC and cognitive functions. These topological abnormalities and disconnections might be potential biomarkers of cognitive impairments in patients with OSA.
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Affiliation(s)
- Li-Ting Chen
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Xiao-Le Fan
- Department of General Surgery, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Hai-Jun Li
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Cheng-Long Ye
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Hong-Hui Yu
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Hui-Zhen Xin
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Hong-Han Gong
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - De-Chang Peng
- Department of Radiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Li-Ping Yan
- Department of Cardiology, People’s Hospital of Jiangxi Province, Nanchang, Jiangxi Province, China
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Park KM, Lee BI, Shin KJ, Ha SY, Park J, Kim TH, Mun CW, Kim SE. Progressive topological disorganization of brain network in focal epilepsy. Acta Neurol Scand 2018; 137:425-431. [PMID: 29344935 DOI: 10.1111/ane.12899] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2017] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Increasing evidence has suggested that epilepsy is a network disease. Graph theory is a mathematical tool that allows for the analysis and quantification of the brain network. We aimed to evaluate the influences of duration of epilepsy on the topological organization of brain network in focal epilepsy patients with normal MRI using the graph theoretical analysis based on diffusion tenor imaging. METHODS We prospectively enrolled 66 patients with focal epilepsy (18/66 patients were newly diagnosed) and 84 healthy subjects. All of the patients with epilepsy had normal MRI on visual inspection. All of the subjects underwent diffusion tensor imaging that was analyzed using graph theory to obtain network measures. RESULTS The measures of characteristic path length and small-worldness in the patients with focal epilepsy were significantly decreased, even after multiple corrections (P < .01). Moreover, the measures including mean clustering coefficient and global efficiency in the patients with epilepsy had strong tendency to decrease compared to those in healthy subjects (P = .0153 and P = .0138, respectively). When comparing the measures among the patients with newly diagnosed/chronic epilepsy and healthy subjects using ANOVA, the characteristic path length (P = .006), small-worldness (P = .032), and global efficiency (P = .004) were significantly different. In addition, the duration of epilepsy was negatively correlated with global efficiency (r = -.249, P = .0454). CONCLUSIONS We newly found a progressive topological disorganization of the brain network in focal epilepsy. In addition, we demonstrated disrupted topological organization in focal epilepsy, shifting toward a more random state.
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Affiliation(s)
- K. M. Park
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
| | - B. I. Lee
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
| | - K. J. Shin
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
| | - S. Y. Ha
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
| | - J. Park
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
| | - T. H. Kim
- Department of Health Science and Technology; Inje University; Gimhae Korea
| | - C. W. Mun
- Department of Health Science and Technology; Inje University; Gimhae Korea
- School of Biomedical Engineering/u-HARC; Inje University; Gimhae Korea
| | - S. E. Kim
- Department of Neurology; Haeundae Paik Hospital; Inje University College of Medicine; Busan Korea
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10
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Parker CS, Clayden JD, Cardoso MJ, Rodionov R, Duncan JS, Scott C, Diehl B, Ourselin S. Structural and effective connectivity in focal epilepsy. NEUROIMAGE-CLINICAL 2017. [PMID: 29527498 PMCID: PMC5842760 DOI: 10.1016/j.nicl.2017.12.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Patients with medically-refractory focal epilepsy may be candidates for neurosurgery and some may require placement of intracranial EEG electrodes to localise seizure onset. Assessing cerebral responses to single pulse electrical stimulation (SPES) may give diagnostically useful data. SPES produces cortico-cortical evoked potentials (CCEPs), which infer effective brain connectivity. Diffusion-weighted images and tractography may be used to estimate structural brain connectivity. This combination provides the opportunity to observe seizure onset and its propagation throughout the brain, spreading contiguously along the cortex explored with electrodes, or non-contiguously. We analysed CCEPs and diffusion tractography in seven focal epilepsy patients and reconstructed the effective and structural brain networks. We aimed to assess the inter-modal similarity of the networks at a large scale across the cortex, the effective and structural connectivity of the ictal-onset zone, and investigate potential mechanisms of non-contiguous seizure spread. We found a significant overlap between structural and effective networks. Effective network CCEP amplitude, baseline variation, and outward connectivity was higher at ictal-onset zones, while structural connection strength within the ictal-onset zone tended to be higher. These findings support the concept of hyperexcitable cortex being associated with seizure generation. The high prevalence of structural and effective connections from the ictal-onset zone to sites of non-contiguous spread suggests that macroscopic structural and effective connections are plausible routes for non-contiguous seizure spread. Inter-modal network agreement was higher than by chance and correlation was low. High CCEP amplitude, baseline variation and outdegree at the ictal-onset zone. Streamline density tended to be higher within the ictal-onset zone. High ictal-onset zone connectivity to early and late seizure spread sites.
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Affiliation(s)
- Christopher S Parker
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, United Kingdom; Developmental Imaging and Biophysics Unit, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.
| | - Jonathan D Clayden
- Developmental Imaging and Biophysics Unit, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - M Jorge Cardoso
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Roman Rodionov
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - John S Duncan
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Catherine Scott
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Beate Diehl
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Sebastien Ourselin
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, United Kingdom
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11
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Pascalau R, Szabo B. Fibre Dissection and Sectional Study of the Major Porcine Cerebral White Matter Tracts. Anat Histol Embryol 2017; 46:378-390. [PMID: 28677169 DOI: 10.1111/ahe.12280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/02/2017] [Indexed: 01/19/2023]
Abstract
White matter anatomy is the basis for numerous applications in neurology, neurosurgery and fundamental neuroscience. Although the porcine brain is frequently used as experimental model in these fields of research, the description of its white matter is not as thorough as in the human brain or other species. Thus, the aim of this study is to describe the porcine white matter tracts in a complex manner. Two stepwise dissection protocols adapted from human anatomy were performed on six adult pig brain hemispheres prepared according to the Klingler method. Other four hemispheres were sectioned along section planes that were chosen similar to the Talairach coordinate system. As a result, three commissural tracts, seven association tracts and one projection tract were identified: corpus callosum, fornix, commissura rostralis, the short-association tracts, fasciculus longitudinalis superior, fasciculus uncinatus, fasciculus longitudinalis inferior, fasciculus occipitofrontalis inferior, cingulum, tractus mamillothalamicus and capsula interna. They were described and illustrated from multiple points of view, focusing on their trajectory, position, dimensions and anatomical relations. All in all, we achieved a three-dimensional understanding of the major tracts. The results are ready to be applied in future imagistic or experimental studies.
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Affiliation(s)
- R Pascalau
- Iuliu Hatieganu University of Medicine and Pharmacy, 8 Babes Street, 400012, Cluj-Napoca, Romania
| | - B Szabo
- Department of Anatomy and Embryology, Iuliu Hatieganu University of Medicine and Pharmacy, 8 Babes Street, 400012, Cluj-Napoca, Romania.,Department of Ophthalmology, Emergency County Hospital, 3-5 Clinicilor Street, 400006, Cluj-Napoca, Romania
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12
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Chen LT, Fan XL, Li HJ, Nie S, Gong HH, Zhang W, Zeng XJ, Long P, Peng DC. Disrupted small-world brain functional network topology in male patients with severe obstructive sleep apnea revealed by resting-state fMRI. Neuropsychiatr Dis Treat 2017; 13:1471-1482. [PMID: 28652747 PMCID: PMC5473494 DOI: 10.2147/ndt.s135426] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that can damage cognitive function. However, the functional network organization remains poorly understood. The aim of this study was to investigate the topological properties of OSA patients using a graph theoretical analysis. PATIENTS AND METHODS A total of 30 male patients with untreated severe OSA and 25 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (MRI) examinations. Clinical and cognitive evaluations were conducted by an experienced psychologist. GRETNA (a toolbox for topological analysis of imaging connectomics) was used to construct the brain functional network and calculate the small-world properties (γ, λ, σ, Eglob, and Eloc). Relationships between these small-world properties and clinical and neuropsychological assessments were investigated in OSA patients. RESULTS The networks of both OSA patients and GSs exhibited efficient small-world topology over the sparsity range of 0.05-0.40. Compared with GSs, the OSA group had significantly decreased γ, but significantly increased λ and σ. The OSA group's brain network showed significantly decreased Eglob (P<0.05) over the sparsity range of 0.09-0.15, but significantly increased Eloc over the sparsity range of 0.23-0.40. In OSA patients, γ was significantly negatively correlated with apnea-hypopnea index (AHI; r=-0.326, P=0.015) and Epworth Sleepiness Scale (ESS; r=-0.274, P=0.043), λ was significantly positively correlated with AHI (r=0.373, P=0.005) and ESS (r=0.269, P=0.047), and σ was significantly negatively correlated with AHI (r=-0.363, P=0.007) and ESS (r=-0.295, P=0.029). CONCLUSION Our results suggest that the high degree of local integration and integrity of the brain connections in OSA patients may be disrupted. The topological alterations of small-world properties may be the mechanism of cognitive impairment in OSA patients. In addition, σ, γ, and λ could be used as a quantitative physiological index for auxiliary clinical diagnoses.
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Affiliation(s)
| | | | | | | | | | | | | | - Ping Long
- Department of Otolaryngology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
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Ould Ismail AAO, Amouzandeh G, Grant SC. Structural connectivity within neural ganglia: A default small-world network. Neuroscience 2016; 337:276-284. [PMID: 27659117 DOI: 10.1016/j.neuroscience.2016.09.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/02/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
Abstract
Diffusion tensor imaging (DTI) provides a unique contrast based on the restricted directionality of water movement in an anisotropic environment. As such, DTI-based tractography can be used to characterize and quantify the structural connectivity within neural tissue. Here, DTI-based connectivity within isolated abdominal ganglia of Aplysia californica (ABG) is analyzed using network theory. In addition to quantifying the regional physical proprieties of the fractional anisotropy and apparent diffusion coefficient, DTI tractography was used to probe inner-connections of local communities, yielding unweighted, undirected graphs that represent community structures. Local and global efficiency, characteristic path lengths and clustering analysis are performed on both experimental and simulated data. The relevant intensity by which these specific nodes communicate is probed through weighted clustering coefficient measurements. Both small-worldness and novel small-world metrics were used as tools to verify the small-world properties for the experimental results. The aim of this manuscript is to categorize the properties exhibited by structural networks in a model neural tissue to derive unique mean field information that quantitatively describe macroscopic connectivity. For ABG, findings demonstrate a default structural network with preferential specific small-world properties when compared to simulated lattice and random networks that are equivalent in order and degree.
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Affiliation(s)
- Abdol Aziz O Ould Ismail
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA; Department of Chemical and Biomedical Engineering, Florida State University, FAMU-FSU College of Engineering, Tallahassee, FL, USA
| | - Ghoncheh Amouzandeh
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA; Department of Physics, Florida State University, Tallahassee, FL, USA
| | - Samuel C Grant
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA; Department of Chemical and Biomedical Engineering, Florida State University, FAMU-FSU College of Engineering, Tallahassee, FL, USA.
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14
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Alexander A, Maroso M, Soltesz I. Organization and control of epileptic circuits in temporal lobe epilepsy. PROGRESS IN BRAIN RESEARCH 2016; 226:127-54. [PMID: 27323941 PMCID: PMC5140277 DOI: 10.1016/bs.pbr.2016.04.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
When studying the pathological mechanisms of epilepsy, there are a seemingly endless number of approaches from the ultrastructural level-receptor expression by EM-to the behavioral level-comorbid depression in behaving animals. Epilepsy is characterized as a disorder of recurrent seizures, which are defined as "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain" (Fisher et al., 2005). Such abnormal activity typically does not occur in a single isolated neuron; rather, it results from pathological activity in large groups-or circuits-of neurons. Here we choose to focus on two aspects of aberrant circuits in temporal lobe epilepsy: their organization and potential mechanisms to control these pathological circuits. We also look at two scales: microcircuits, ie, the relationship between individual neurons or small groups of similar neurons, and macrocircuits, ie, the organization of large-scale brain regions. We begin by summarizing the large body of literature that describes the stereotypical anatomical changes in the temporal lobe-ie, the anatomical basis of alterations in microcircuitry. We then offer a brief introduction to graph theory and describe how this type of mathematical analysis, in combination with computational neuroscience techniques and using parameters obtained from experimental data, can be used to postulate how microcircuit alterations may lead to seizures. We then zoom out and look at the changes which are seen over large whole-brain networks in patients and animal models, and finally we look to the future.
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Affiliation(s)
- A Alexander
- Stanford University, Stanford, CA, United States
| | - M Maroso
- Stanford University, Stanford, CA, United States
| | - I Soltesz
- Stanford University, Stanford, CA, United States.
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15
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Investigating Brain Network Characteristics Interrupted by Covert White Matter Injury in Patients with Moyamoya Disease: Insights from Graph Theoretical Analysis. World Neurosurg 2016; 89:654-665.e2. [DOI: 10.1016/j.wneu.2015.11.100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/30/2015] [Accepted: 11/30/2015] [Indexed: 12/30/2022]
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Qi S, Meesters S, Nicolay K, Ter Haar Romeny BM, Ossenblok P. Structural Brain Network: What is the Effect of LiFE Optimization of Whole Brain Tractography? Front Comput Neurosci 2016; 10:12. [PMID: 26909034 PMCID: PMC4754446 DOI: 10.3389/fncom.2016.00012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 01/29/2016] [Indexed: 01/21/2023] Open
Abstract
Structural brain networks constructed based on diffusion-weighted MRI (dMRI) have provided a systems perspective to explore the organization of the human brain. Some redundant and nonexistent fibers, however, are inevitably generated in whole brain tractography. We propose to add one critical step while constructing the networks to remove these fibers using the linear fascicle evaluation (LiFE) method, and study the differences between the networks with and without LiFE optimization. For a cohort of nine healthy adults and for 9 out of the 35 subjects from Human Connectome Project, the T 1-weighted images and dMRI data are analyzed. Each brain is parcellated into 90 regions-of-interest, whilst a probabilistic tractography algorithm is applied to generate the original connectome. The elimination of redundant and nonexistent fibers from the original connectome by LiFE creates the optimized connectome, and the random selection of the same number of fibers as the optimized connectome creates the non-optimized connectome. The combination of parcellations and these connectomes leads to the optimized and non-optimized networks, respectively. The optimized networks are constructed with six weighting schemes, and the correlations of different weighting methods are analyzed. The fiber length distributions of the non-optimized and optimized connectomes are compared. The optimized and non-optimized networks are compared with regard to edges, nodes and networks, within a sparsity range of 0.75-0.95. It has been found that relatively more short fibers exist in the optimized connectome. About 24.0% edges of the optimized network are significantly different from those in the non-optimized network at a sparsity of 0.75. About 13.2% of edges are classified as false positives or the possible missing edges. The strength and betweenness centrality of some nodes are significantly different for the non-optimized and optimized networks, but not the node efficiency. The normalized clustering coefficient, the normalized characteristic path length and the small-worldness are higher in the optimized network weighted by the fiber number than in the non-optimized network. These observed differences suggest that LiFE optimization can be a crucial step for the construction of more reasonable and more accurate structural brain networks.
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Affiliation(s)
- Shouliang Qi
- Sino-Dutch Biomedical and Information Engineering School, Northeastern UniversityShenyang, China; Academic Center for Epileptology Kempenhaeghe and Maastricht UMC+Heeze, Netherlands; Department of Biomedical Engineering, Eindhoven University of TechnologyEindhoven, Netherlands
| | - Stephan Meesters
- Academic Center for Epileptology Kempenhaeghe and Maastricht UMC+Heeze, Netherlands; Department of Mathematics and Computer Science, Eindhoven University of TechnologyEindhoven, Netherlands
| | - Klaas Nicolay
- Department of Biomedical Engineering, Eindhoven University of Technology Eindhoven, Netherlands
| | - Bart M Ter Haar Romeny
- Sino-Dutch Biomedical and Information Engineering School, Northeastern UniversityShenyang, China; Department of Biomedical Engineering, Eindhoven University of TechnologyEindhoven, Netherlands
| | - Pauly Ossenblok
- Academic Center for Epileptology Kempenhaeghe and Maastricht UMC+Heeze, Netherlands; Department of Biomedical Engineering, Eindhoven University of TechnologyEindhoven, Netherlands
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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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Kamiya K, Amemiya S, Suzuki Y, Kunii N, Kawai K, Mori H, Kunimatsu A, Saito N, Aoki S, Ohtomo K. Machine Learning of DTI Structural Brain Connectomes for Lateralization of Temporal Lobe Epilepsy. Magn Reson Med Sci 2015; 15:121-9. [PMID: 26346404 DOI: 10.2463/mrms.2015-0027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE We analyzed the ability of a machine learning approach that uses diffusion tensor imaging (DTI) structural connectomes to determine lateralization of epileptogenicity in temporal lobe epilepsy (TLE). MATERIALS AND METHODS We analyzed diffusion tensor and 3-dimensional (3D) T1-weighted images of 44 patients with TLE (right, 15, left, 29; mean age, 33.0 ± 11.6 years) and 14 age-matched controls. We constructed a whole brain structural connectome for each subject, calculated graph theoretical network measures, and used a support vector machine (SVM) for classification among 3 groups (right TLE versus controls, left TLE versus controls, and right TLE versus left TLE) following a feature reduction process with sparse linear regression. RESULTS In left TLE, we found a significant decrease in local efficiency and the clustering coefficient in several brain regions, including the left posterior cingulate gyrus, left cuneus, and both hippocampi. In right TLE, the right hippocampus showed reduced nodal degree, clustering coefficient, and local efficiency. With use of the leave-one-out cross-validation strategy, the SVM classifier achieved accuracy of 75.9 to 89.7% for right TLE versus controls, 74.4 to 86.0% for left TLE versus controls, and 72.7 to 86.4% for left TLE versus right TLE. CONCLUSION Machine learning of graph theoretical measures from the DTI structural connectome may give support to lateralization of the TLE focus. The present good discrimination between left and right TLE suggests that, with further refinement, the classifier should improve presurgical diagnostic confidence.
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