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Liu Y, Jia Y, Sun H, Sun L, Wang Y, Xu Q, He Y, Chang X, Guo D, Shi M, Chen GC, Zheng J, Zhu Z. Genetic analyses identify brain imaging-derived phenotypes associated with the risk of intracerebral hemorrhage. Cereb Cortex 2024; 34:bhad518. [PMID: 38185989 DOI: 10.1093/cercor/bhad518] [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: 11/08/2023] [Revised: 12/08/2023] [Accepted: 12/09/2023] [Indexed: 01/09/2024] Open
Abstract
Previous observational studies have reported associations between brain imaging-derived phenotypes (IDPs) and intracerebral hemorrhage (ICH), but the causality between them remains uncertain. We aimed to investigate the potential causal relationship between IDPs and ICH by a two-sample Mendelian randomization (MR) study. We selected genetic instruments for 363 IDPs from a genome-wide association study (GWASs) based on the UK Biobank (n = 33,224). Summary-level data on ICH was derived from a European-descent GWAS with 1,545 cases and 1,481 controls. Inverse variance weighted MR method was applied in the main analysis to investigate the associations between IDPs and ICH. Reverse MR analyses were performed for significant IDPs to examine the reverse causation for the identified associations. Among the 363 IDPs, isotropic or free water volume fraction (ISOVF) in the anterior limb of the left internal capsule was identified to be associated with the risk of ICH (OR per 1-SD increase, 4.62 [95% CI, 2.18-9.81], P = 6.63 × 10-5). In addition, the reverse MR analysis indicated that ICH had no effect on ISOVF in the anterior limb of the left internal capsule (beta, 0.010 [95% CI, -0.010-0.030], P = 0.33). MR-Egger regression analysis showed no directional pleiotropy for the association between ISOVF and ICH, and sensitivity analyses with different MR models further confirmed these findings. ISOVF in the anterior limb of the left internal capsule might be a potential causal mediator of ICH, which may provide predictive guidance for the prevention of ICH. Further studies are warranted to replicate our findings and clarify the underlying mechanisms.
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Affiliation(s)
- Yi Liu
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Yiming Jia
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Hongyan Sun
- Department of Medical Imaging, 11 Guangqian Road, Xiangcheng District, The Affiliated Guangji Hospital of Soochow University, Suzhou, China
| | - Lulu Sun
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Yinan Wang
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Qingyun Xu
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Yu He
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Xinyue Chang
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Daoxia Guo
- School of Nursing, 333 Ganjiang East Road, Gusu District, Suzhou Medical College of Soochow University, Suzhou, China
| | - Mengyao Shi
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
| | - Guo-Chong Chen
- Department of Nutrition and Food Hygiene, School of Public Health, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, China
| | - Jin Zheng
- Department of Neurology, Minhang Hospital, 170 Xinsong Road, Xinzhuang Town, Minhang District, Fudan University, Shanghai, China
| | - Zhengbao Zhu
- Department of Epidemiology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, 199 Renai Road, Industrial Park District, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, China
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Demirtaş OK, Güngör A, Çeltikçi P, Çeltikçi E, Munoz-Gualan AP, Doğulu FH, Türe U. Microsurgical anatomy and insular connectivity of the cerebral opercula. J Neurosurg 2022; 137:1509-1523. [PMID: 35303697 DOI: 10.3171/2021.12.jns212297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/20/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Radiological, anatomical, and electrophysiological studies have shown the insula and cerebral opercula to have extremely high functionality. Because of this complexity, interventions in this region cause higher morbidity compared to those in other areas of the brain. In most early studies of the insula and white matter pathways, insular dissection was begun after the opercula were removed. In this study, the authors examined the insula and deep white matter pathways to evaluate the insula as a whole with the surrounding opercula. METHODS Twenty formalin-fixed adult cerebral hemispheres were studied using fiber microdissection techniques and examination of sectional anatomy. Dissections were performed from lateral to medial, medial to lateral, inferior to superior, and superior to inferior. A silicone brain model was used to show the normal gyral anatomy. Sections and fibers found at every stage of dissection were photographed with a professional camera. MRI tractography studies were used to aid understanding of the dissections. RESULTS The relationships between the insula and cerebral opercula were investigated in detail through multiple dissections and sections. The relationship of the extreme and external capsules with the surrounding opercula and the fronto-occipital fasciculus with the fronto-orbital operculum was demonstrated. These findings were correlated with the tractography studies. Fibers of the extreme capsule connect the medial aspect of the opercula with the insula through the peri-insular sulcus. Medial to lateral dissections were followed with the removal of the central core structures, and in the last step, the medial surface of the cerebral opercula was evaluated in detail. CONCLUSIONS This anatomical study clarifies our understanding of the insula and cerebral opercula, which have complex anatomical and functional networks. This study also brings a new perspective to the connection of the insula and cerebral opercula via the extreme and external capsules.
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Affiliation(s)
- Oğuz Kağan Demirtaş
- 1Department of Neurosurgery, Gazi University Hospital, Ankara
- 2Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul
- 3Department of Neurosurgery, Sincan Nafiz Körfez State Hospital, Ankara
| | - Abuzer Güngör
- 2Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul
- 4Department of Neurosurgery, Bakirköy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Istanbul
| | - Pınar Çeltikçi
- 5Department of Radiology, Ankara Bilkent City Hospital, Ankara, Turkey; and
| | - Emrah Çeltikçi
- 1Department of Neurosurgery, Gazi University Hospital, Ankara
| | - Alberth Patricio Munoz-Gualan
- 2Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul
- 6Department of Nervous Disease and Neurosurgery, Peoples' Friendship University of Russia, Moscow, Russia
| | | | - Uğur Türe
- 2Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul
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Handedness and midsagittal corpus callosum morphology: a meta-analytic evaluation. Brain Struct Funct 2021; 227:545-559. [PMID: 34851460 PMCID: PMC8843913 DOI: 10.1007/s00429-021-02431-4] [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: 04/29/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022]
Abstract
Following a series of seminal studies in the 1980s, left or mixed hand preference is widely thought to be associated with a larger corpus callosum than right handedness, influencing the interpretation of findings and various theories related to interhemispheric processing, brain lateralisation, and hand preference. Recent reviews, however, find inconsistencies in the literature and cast doubt on the existence of such an association. The present study was conducted to clarify the relationship between hand preference and callosal morphology in a series of meta-analyses. For this purpose, articles were identified via a search in PubMed and Web Of Science databases. Studies reporting findings relating to handedness (assessed as hand preference) and corpus-callosum morphology in healthy participants were considered eligible. On the basis of a total of k = 24 identified studies and databases, random-effects meta-analyses were conducted considering four different group comparisons: (a) dominantly right- (dRH) and left-hand preference (dLH), (b) consistent right (cRH) and non-cRH preference, (c) cRH with mixed-hand preference (MH), and (d) cRH with consistent left-hand hand preference (cLH). For none of these meta-analyses did we find a significant effect of hand preference, and narrow confidence intervals suggest that the existence of population effects larger than 1% explained variance could be excluded. For example, considering the comparison of dRH and dLH (k = 14 studies; 1910 dRH and 646 dLH participants) the mean effect size was Hedge’s g = 0.016 (95% confidence interval: − 0.12 to 0.15; explained variance: < 0.001%). Thus, the common practice of assuming an increase in callosal connectivity based on mixed or left hand preference is likely invalid.
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Honnedevasthana Arun A, Connelly A, Smith RE, Calamante F. Characterisation of white matter asymmetries in the healthy human brain using diffusion MRI fixel-based analysis. Neuroimage 2020; 225:117505. [PMID: 33147511 DOI: 10.1016/j.neuroimage.2020.117505] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/18/2020] [Accepted: 10/22/2020] [Indexed: 12/13/2022] Open
Abstract
The diffusion tensor model for diffusion MRI has been used extensively to study asymmetry in the human brain white matter. However, given the limitations of the tensor model, the nature of any underlying asymmetries remains uncertain, particularly in crossing fibre regions. Here, we provide a more robust characterisation of human brain white matter asymmetries based on fibre-specific diffusion MRI metrics and a whole-brain data-driven approach. We used high-quality diffusion MRI data (n = 100) from the Human Connectome Project, the spherical deconvolution model for fibre orientation distribution estimation, and the Fixel-Based Analysis framework to utilise crossing fibre information in registration, data smoothing and statistical inference. We found many significant asymmetries, widespread throughout the brain white matter, with both left>right and right>left dominances observed in different pathways. No influences of sex, age, or handedness on asymmetry were found. We also report on the relative contributions of microstructural and morphological white matter properties toward the asymmetry findings. Our findings should provide important information to future studies focussing on how these asymmetries are affected by disease, development/ageing, or how they correlate to functional/cognitive measures.
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Affiliation(s)
- Arush Honnedevasthana Arun
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; The University of Sydney, School of Biomedical Engineering, Sydney, Australia
| | - Alan Connelly
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Robert E Smith
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Fernando Calamante
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; The University of Sydney, Sydney Imaging, Sydney, Australia; The University of Sydney, School of Biomedical Engineering, Sydney, Australia.
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Abstract
The development and persistence of laterality is a key feature of human motor behavior, with the asymmetry of hand use being the most prominent. The idea that asymmetrical functions of the hands reflect asymmetries in terms of structural and functional brain organization has been tested many times. However, despite advances in laterality research and increased understanding of this population-level bias, the neural basis of handedness remains elusive. Recent developments in diffusion magnetic resonance imaging enabled the exploration of lateralized motor behavior also in terms of white matter and connectional neuroanatomy. Despite incomplete and partly inconsistent evidence, structural connectivity of both intrahemispheric and interhemispheric white matter seems to differ between left and right-handers. Handedness was related to asymmetry of intrahemispheric pathways important for visuomotor and visuospatial processing (superior longitudinal fasciculus), but not to projection tracts supporting motor execution (corticospinal tract). Moreover, the interindividual variability of the main commissural pathway corpus callosum seems to be associated with handedness. The review highlights the importance of exploring new avenues for the study of handedness and presents the latest state of knowledge that can be used to guide future neuroscientific and genetic research.
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Affiliation(s)
- Sanja Budisavljevic
- Department of General Psychology, University of Padova, Padova, Italy.,The School of Medicine, University of St. Andrews, St. Andrews, UK
| | - Umberto Castiello
- Department of General Psychology, University of Padova, Padova, Italy
| | - Chiara Begliomini
- Department of General Psychology, University of Padova, Padova, Italy
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Nordin T, Zsigmond P, Pujol S, Westin CF, Wårdell K. White matter tracing combined with electric field simulation - A patient-specific approach for deep brain stimulation. Neuroimage Clin 2019; 24:102026. [PMID: 31795055 PMCID: PMC6880013 DOI: 10.1016/j.nicl.2019.102026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/04/2019] [Accepted: 10/02/2019] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Deep brain stimulation (DBS) in zona incerta (Zi) is used for symptom alleviation in essential tremor (ET). Zi is positioned along the dentato-rubro-thalamic tract (DRT). Electric field simulations with the finite element method (FEM) can be used for estimation of a volume where the stimulation affects the tissue by applying a fixed isolevel (VDBS). This work aims to develop a workflow for combined patient-specific electric field simulation and white matter tracing of the DRT, and to investigate the influence on the VDBS from different brain tissue models, lead design and stimulation modes. The novelty of this work lies in the combination of all these components. METHOD Patients with ET were implanted in Zi (lead 3389, n = 3, voltage mode; directional lead 6172, n = 1, current mode). Probabilistic reconstruction from diffusion MRI (dMRI) of the DRT (n = 8) was computed with FSL Toolbox. Brain tissue models were created for each patient (two homogenous, one heterogenous isotropic, one heterogenous anisotropic) and the respective VDBS (n = 48) calculated from the Comsol Multiphysics FEM simulations. The DRT and VDBS were visualized with 3DSlicer and superimposed on the preoperative T2 MRI, and the common volumes calculated. Dice Coefficient (DC) and level of anisotropy were used to evaluate and compare the brain models. RESULT Combined patient-specific tractography and electric field simulation was designed and evaluated, and all patients showed benefit from DBS. All VDBS overlapped the reconstructed DRT. Current stimulation showed prominent difference between the tissue models, where the homogenous grey matter deviated most (67 < DC < 69). Result from heterogenous isotropic and anisotropic models were similar (DC > 0.95), however the anisotropic model consistently generated larger volumes related to a greater extension of the electric field along the DBS lead. Independent of tissue model, the steering effect of the directional lead was evident and consistent. CONCLUSION A workflow for patient-specific electric field simulations in combination with reconstruction of DRT was successfully implemented. Accurate tissue classification is essential for electric field simulations, especially when using the current control stimulation. With an accurate targeting and tractography reconstruction, directional leads have the potential to tailor the electric field into the desired region.
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Affiliation(s)
- Teresa Nordin
- Department of Biomedical Engineering, Linköping University, Sweden.
| | - Peter Zsigmond
- Department of Neurosurgery and Clinical and Experimental Medicine, Linköping University, Sweden
| | - Sonia Pujol
- Laboratory of Mathematics in Imaging, Brigham and Women's Hospital, Harvard Medical School, USA; Surgical Planning Laboratory, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, USA
| | - Carl-Fredrik Westin
- Laboratory of Mathematics in Imaging, Brigham and Women's Hospital, Harvard Medical School, USA
| | - Karin Wårdell
- Department of Biomedical Engineering, Linköping University, Sweden
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Thomas B, Sunaert S. Diffusion Tensor Imaging: Technique, Clinical and Research Applications. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/197140090501800403] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- B. Thomas
- Department of Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum; Kerala, India
| | - S. Sunaert
- Department of Radiology, University Hospitals, KUL; Leuven, Belgium
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Vora M, Kumar S, Sharma S, Sharma S, Makhaik S, Sood RG. Advanced magnetic resonance neuroimaging in bulbar and limb onset early amyotrophic lateral sclerosis. J Neurosci Rural Pract 2016; 7:102-8. [PMID: 26933355 PMCID: PMC4750305 DOI: 10.4103/0976-3147.165423] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Introduction: Amyotrophic lateral sclerosis (ALS) is a fatal and most common motor neuron disease, caused by progressive loss of motor neurons. Diffusion tensor imaging (DTI) and magnetic resonance spectroscopic (MRS) studies detect pathological changes in neuronal fibers in vivo. We evaluated the role of DTI and MRS in early course of the disease, which may prove beneficial in the early diagnosis and better management. Materials and Methods: Twenty-one patients with ALS and 13 age-matched controls received 1.5T DTI and three-dimensional multi-voxel MRS. Fractional anisotropy (FA), apparent diffusion coefficient, N-acetyl aspartate (NAA)/Creatine (Cr), and NAA/Choline (Ch) ratios were analyzed in various regions of the brain and compared with healthy controls. ALS patients were classified as definite, possible, and probable category, and patients were also studied in limb versus bulbar onset. Results: Decreased FA and increase mean diffusivity values in regions of corticospinal tract (CST) and corpus callosum (CC) was consistent finding in definite and probable disease category (P < 0.05). In possible disease, CC involvement was not significant. NAA/Cr and NAA/Ch ratios were lower in CC and regions of CST. However, in possible disease, CC involvement was not significant, while regions of CST were showing significant reduction in NAA/Cr and NAA/Ch ratios (P < 0.05). Conclusion: DTI and MRS detect changes associated with ALS even in the early phase of the disease. Bulbar onset and limb onset ALS patients show different pattern of involvement. Extramotor involvement suggested by CC involvement is a feature seen in bulbar onset patient and can suggest poor outcome in such patients. The present findings may be helpful for designing further studies in the direction of more early diagnosis of disease and its management.
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Affiliation(s)
- Maulik Vora
- Department of Radiodiagnosis and Imaging, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
| | - Suresh Kumar
- Department of Radiodiagnosis and Imaging, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
| | - Sanjiv Sharma
- Department of Radiodiagnosis and Imaging, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
| | - Sudhir Sharma
- Department of Neurology, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
| | - Sushma Makhaik
- Department of Radiodiagnosis and Imaging, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
| | - R G Sood
- Department of Radiodiagnosis and Imaging, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
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Abstract
Neuroimaging studies have identified patterns of brain abnormalities in various stages of schizophrenia, but whether these abnormalities reflect primary factors associated with the causes of illness or secondary phenomena such as medications has been unclear. Recent work conducted within the prodromal risk paradigm suggests that progressive change in brain structure and function occurs around the time when clinically high-risk individuals transition into full-blown psychosis, effects that cannot be explained by exposure to medications or illness chronicity. This article reviews recent work bearing on the question of the timing of onset and course of brain changes, focusing on structural MRI, diffusion tensor imaging, and resting state connectivity MRI, in association with the onset and course of psychosis. We conclude with a consideration of potential mechanisms underlying progressive tissue changes during the prodromal phase of schizophrenia and implications for prevention.
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Affiliation(s)
- Yoonho Chung
- Deparment of Psychology, Yale University, New Haven CT
| | - Tyrone D. Cannon
- Deparment of Psychology, Yale University, New Haven CT
- Department of Psychiatry, Yale University, New Haven CT
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Wigand M, Kubicki M, von Hohenberg CC, Leicht G, Karch S, Eckbo R, Pelavin PE, Hawley K, Rujescu D, Bouix S, Shenton ME, Mulert C. Auditory verbal hallucinations and the interhemispheric auditory pathway in chronic schizophrenia. World J Biol Psychiatry 2015; 16:31-44. [PMID: 25224883 PMCID: PMC4698973 DOI: 10.3109/15622975.2014.948063] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The interhemispheric auditory pathway has been shown to play a crucial role in the processing of acoustic stimuli, and alterations of structural and functional connectivity between bilateral auditory areas are likely relevant to the pathogenesis of auditory verbal hallucinations (AVHs). The aim of this study was to examine this pathway in patients with chronic schizophrenia regarding their lifetime history of AVHs. METHODS DTI scans were acquired from 33 healthy controls (HC), 24 schizophrenia patients with a history of AVHs (LT-AVH) and nine schizophrenia patients without any lifetime hallucinations (N-LT-AVH). The interhemispheric auditory fibre bundles were extracted using streamline tractography. Subsequently, diffusivity indices, namely Fractional Anisotropy (FA), Trace, Mode, Axial and Radial diffusivity, were calculated. RESULTS FA was decreased over the entire pathway in LT-AVH compared with N-LT-AVH. Moreover, LT-AVH displayed decreased FA and Mode as well as increased radial diffusivity in the midsagittal section of the fibre tract. CONCLUSIONS These findings indicate complex microstructural changes in the interhemispheric auditory pathway of schizophrenia patients with a history of AVHs. Alterations appear to be absent in patients who have never hallucinated.
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Affiliation(s)
- Marlene Wigand
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany,Department of Psychiatry, Psychiatry Neuroimaging Branch, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Marek Kubicki
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Radiology, Surgical Planning Laboratory, MRI Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Christian Clemm von Hohenberg
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany,Department of Psychiatry, Psychiatry Neuroimaging Branch, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Gregor Leicht
- Department of Psychiatry, Psychiatry Neuroimaging Branch, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Karch
- Department of Psychiatry, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Ryan Eckbo
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Paula E. Pelavin
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Kathryn Hawley
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Dan Rujescu
- Department of Psychiatry, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany,Department of Psychiatry, University Hospital and Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sylvain Bouix
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Radiology, Surgical Planning Laboratory, MRI Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Martha E. Shenton
- Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Radiology, Surgical Planning Laboratory, MRI Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA,Department of Psychiatry, Veterans Affairs Boston Healthcare System and Harvard Medical School, Brockton, MA, USA
| | - Christoph Mulert
- Department of Psychiatry, Psychiatry Neuroimaging Branch, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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Dunst B, Benedek M, Koschutnig K, Jauk E, Neubauer AC. Sex differences in the IQ-white matter microstructure relationship: a DTI study. Brain Cogn 2014; 91:71-8. [PMID: 25238623 PMCID: PMC4245721 DOI: 10.1016/j.bandc.2014.08.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 08/11/2014] [Accepted: 08/23/2014] [Indexed: 12/29/2022]
Abstract
Sex differences in the relationship between general intelligence and brain structure are a topic of increasing research interest. Early studies focused mainly on gray and white matter differences using voxel-based morphometry, while more recent studies investigated neural fiber tracts using diffusion tensor imaging (DTI) to analyze the white matter microstructure. In this study we used tract-based spatial statistics (TBSS) on DTI to test how intelligence is associated with brain diffusion indices and to see whether this relationship differs between men and women. 63 Men and women divided into groups of lower and higher intelligence were selected. Whole-brain DTI scans were analyzed using TBSS calculating maps of fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). The results reveal that the white matter microstructure differs between individuals as a function of intelligence and sex. In men, higher intelligence was related to higher FA and lower RD in the corpus callosum. In women, in contrast, intelligence was not related to the white matter microstructure. The higher values of FA and lower values of RD suggest that intelligence is associated with higher myelination and/or a higher number of axons particularly in men. This microstructural difference in the corpus callosum may increase cognitive functioning by reducing inter-hemispheric transfer time and thus account for more efficient brain functioning in men.
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Affiliation(s)
- Beate Dunst
- Department of Psychology, University of Graz, Austria.
| | | | | | - Emanuel Jauk
- Department of Psychology, University of Graz, Austria.
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Prasad G, Joshi SH, Jahanshad N, Villalon-Reina J, Aganj I, Lenglet C, Sapiro G, McMahon KL, de Zubicaray GI, Martin NG, Wright MJ, Toga AW, Thompson PM. Automatic clustering and population analysis of white matter tracts using maximum density paths. Neuroimage 2014; 97:284-95. [PMID: 24747738 DOI: 10.1016/j.neuroimage.2014.04.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/24/2014] [Accepted: 04/08/2014] [Indexed: 10/25/2022] Open
Abstract
We introduce a framework for population analysis of white matter tracts based on diffusion-weighted images of the brain. The framework enables extraction of fibers from high angular resolution diffusion images (HARDI); clustering of the fibers based partly on prior knowledge from an atlas; representation of the fiber bundles compactly using a path following points of highest density (maximum density path; MDP); and registration of these paths together using geodesic curve matching to find local correspondences across a population. We demonstrate our method on 4-Tesla HARDI scans from 565 young adults to compute localized statistics across 50 white matter tracts based on fractional anisotropy (FA). Experimental results show increased sensitivity in the determination of genetic influences on principal fiber tracts compared to the tract-based spatial statistics (TBSS) method. Our results show that the MDP representation reveals important parts of the white matter structure and considerably reduces the dimensionality over comparable fiber matching approaches.
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Affiliation(s)
- Gautam Prasad
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA
| | - Shantanu H Joshi
- Department of Neurology, University of California Los Angeles, CA, USA
| | - Neda Jahanshad
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA
| | - Julio Villalon-Reina
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA
| | - Iman Aganj
- Martinos Center for Biomedical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Christophe Lenglet
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Guillermo Sapiro
- Dept. of Electrical and Computer Engineering, Computer Science, Duke University, NC, USA; Dept. of Biomedical Engineering, Duke University, NC, USA
| | - Katie L McMahon
- Center for Advanced Imaging, University of Queensland, Brisbane, Australia
| | | | | | - Margaret J Wright
- School of Psychology, University of Queensland, Brisbane, Australia; QIMR Berghofer Medical Research Institute, Herston, Australia
| | - Arthur W Toga
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Dept. of Neurology, Psychiatry, Engineering, Radiology, University of Southern California, Los Angeles, CA, USA; Dept. of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Paul M Thompson
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Laboratory of Neuro Imaging, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Department of Neurology, University of California Los Angeles, CA, USA; Dept. of Neurology, Psychiatry, Engineering, Radiology, University of Southern California, Los Angeles, CA, USA; Dept. of Ophthalmology, University of Southern California, Los Angeles, CA, USA; Department of Pediatrics, University of Southern California, Los Angeles, CA, USA.
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High-resolution magnetic resonance microscopy and diffusion tensor imaging to assess brain structural abnormalities in the murine mucopolysaccharidosis VII model. J Neuropathol Exp Neurol 2014; 73:39-49. [PMID: 24335527 DOI: 10.1097/nen.0000000000000023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
High-resolution microscopic magnetic resonance imaging (μMRI) and diffusion tensor imaging (DTI) were performed to characterize brain structural abnormalities in a mouse model of mucopolysaccharidosis type VII (MPS VII). Microscopic magnetic resonance imaging demonstrated a decrease in the volume of anterior commissure and corpus callosum and a slight increase in the volume of the hippocampus in MPS VII versus wild-type mice. Diffusion tensor imaging indices were analyzed in gray and white matter. In vivo and ex vivo DTI demonstrated significantly reduced fractional anisotropy in the anterior commissure, corpus callosum, external capsule, and hippocampus in MPS VII versus control brains. Significantly increased mean diffusivity was also found in the anterior commissure and corpus callosum from ex vivo DTI. Significantly reduced linear anisotropy was observed from the hippocampus from in vivo DTI, whereas significantly decreased planar anisotropy and spherical anisotropy were observed in the external capsule from only ex vivo DTI. There were corresponding morphologic differences in the brains of MPS VII mice by hematoxylin and eosin staining. Luxol fast blue staining demonstrated less intense staining of the corpus callosum and external capsule; myelin abnormalities in the corpus callosum were also demonstrated quantitatively in toluidine blue-stained sections and confirmed by electron microscopy. These results demonstrate the potential for μMRI and DTI for quantitative assessment of brain pathology in murine models of brain diseases.
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Abstract
Epilepsy is the most common serious neurological disease. Seizures are refractory to medication in approximately 30% of patients with focal epilepsy, and surgical treatment is potentially curative should the epileptic focus be accurately localized. MRI has revolutionized the investigation of such patients; however, up to 20% of patients with refractory focal epilepsy have an undetermined etiological basis for their epilepsy despite extensive investigation. Diffusion imaging is an advanced MRI technique that is sensitive to the molecular displacement of water molecules and provides additional information on the microstructural arrangement of tissue. Both qualitative and quantitative analyses of the interictal and peri-ictal states are possible and provide valuable insights into the epileptic brain in vivo. Furthermore, advanced postacquisition processing can reveal additional information on, for example, anatomical connectivity. The description, application and limitations of diffusion imaging in epilepsy are the focus of this review. Future directions of research required in this area are also discussed in the context of existing literature.
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Affiliation(s)
- Fergus J Rugg-Gunn
- Institute of Neurology, Department of Clinical & Experimental Epilepsy, University College London, Queen Square, London, UK.
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Shaaban MA, Alloush TK, Ibrahim MH, Abd el bar A, Morad SH. Volumetric Assessment of Corticospinal Tract Infiltration by Astrocytoma Using Diffusion Tensor Tractography. OPEN JOURNAL OF MEDICAL IMAGING 2014; 04:65-71. [DOI: 10.4236/ojmi.2014.42009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Damion RA, Radjenovic A, Ingham E, Jin Z, Ries ME. Orthogonal invariant sets of the diffusion tensor and the development of a curvilinear set suitable for low-anisotropy tissues. PLoS One 2013; 8:e78798. [PMID: 24244366 PMCID: PMC3823940 DOI: 10.1371/journal.pone.0078798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 09/24/2013] [Indexed: 11/19/2022] Open
Abstract
We develop a curvilinear invariant set of the diffusion tensor which may be applied to Diffusion Tensor Imaging measurements on tissues and porous media. This new set is an alternative to the more common invariants such as fractional anisotropy and the diffusion mode. The alternative invariant set possesses a different structure to the other known invariant sets; the second and third members of the curvilinear set measure the degree of orthotropy and oblateness/prolateness, respectively. The proposed advantage of these invariants is that they may work well in situations of low diffusion anisotropy and isotropy, as is often observed in tissues such as cartilage. We also explore the other orthogonal invariant sets in terms of their geometry in relation to eigenvalue space; a cylindrical set, a spherical set (including fractional anisotropy and the mode), and a log-Euclidean set. These three sets have a common structure. The first invariant measures the magnitude of the diffusion, the second and third invariants capture aspects of the anisotropy; the magnitude of the anisotropy and the shape of the diffusion ellipsoid (the manner in which the anisotropy is realised). We also show a simple method to prove the orthogonality of the invariants within a set.
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Affiliation(s)
- Robin A. Damion
- School of Physics and Astronomy, University of Leeds, Leeds, West Yorkshire, United Kingdom
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, West Yorkshire, United Kingdom
| | - Aleksandra Radjenovic
- National Institute for Health Research, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, University of Leeds, Leeds, West Yorkshire, United Kingdom
- * E-mail: (AR); (MER)
| | - Eileen Ingham
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, West Yorkshire, United Kingdom
| | - Zhongmin Jin
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, West Yorkshire, United Kingdom
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, People’s Republic of China
| | - Michael E. Ries
- School of Physics and Astronomy, University of Leeds, Leeds, West Yorkshire, United Kingdom
- * E-mail: (AR); (MER)
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Freitag MT, van Bruggen T, Fritzsche KH, Henze R, Brunner R, Parzer P, Resch F, Stieltjes B. Reduced lateralization in early onset schizophrenia. Neurosci Lett 2013; 537:23-8. [DOI: 10.1016/j.neulet.2013.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 12/18/2012] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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Wiemker R, Klinder T, Bergtholdt M, Meetz K, Carlsen IC, Bülow T. A radial structure tensor and its use for shape-encoding medical visualization of tubular and nodular structures. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2013; 19:353-366. [PMID: 22689078 DOI: 10.1109/tvcg.2012.136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The concept of curvature and shape-based rendering is beneficial for medical visualization of CT and MRI image volumes. Color-coding of local shape properties derived from the analysis of the local Hessian can implicitly highlight tubular structures such as vessels and airways, and guide the attention to potentially malignant nodular structures such as tumors, enlarged lymph nodes, or aneurysms. For some clinical applications, however, the evaluation of the Hessian matrix does not yield satisfactory renderings, in particular for hollow structures such as airways, and densely embedded low contrast structures such as lymph nodes. Therefore, as a complement to Hessian-based shape-encoding rendering, this paper introduces a combination of an efficient sparse radial gradient sampling scheme in conjunction with a novel representation, the radial structure tensor (RST). As an extension of the well-known general structure tensor, which has only positive definite eigenvalues, the radial structure tensor correlates position and direction of the gradient vectors in a local neighborhood, and thus yields positive and negative eigenvalues which can be used to discriminate between different shapes. As Hessian-based rendering, also RST-based rendering is ideally suited for GPU implementation. Feedback from clinicians indicates that shape-encoding rendering can be an effective image navigation tool to aid diagnostic workflow and quality assurance.
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Furtula J, Johnsen B, Frandsen J, Rodell A, Christensen PB, Pugdahl K, Fuglsang-Frederiksen A. Upper motor neuron involvement in amyotrophic lateral sclerosis evaluated by triple stimulation technique and diffusion tensor MRI. J Neurol 2013; 260:1535-44. [PMID: 23299622 DOI: 10.1007/s00415-012-6824-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/21/2012] [Accepted: 12/24/2012] [Indexed: 11/25/2022]
Abstract
The objective of this study was to evaluate the diagnostic value of triple stimulation technique (TST) and diffusion tensor imaging (DTI) tractography as markers of upper motor neuron (UMN) degeneration in amyotrophic lateral sclerosis (ALS). Fourteen ALS patients fulfilling the El Escorial criteria and 30 control subjects participated in the study. TST amplitude and area ratio were used as an estimate of the degree of central motor conduction failure. DTI fractional anisotropy was used as a quantitative measure of the structural integrity of the corticospinal tract and the posterior limb of the internal capsule. Mean TST amplitude and area ratio were lower in patients than controls, while there were no differences in mean fractional anisotropy of the corticospinal tract or the posterior limb of the internal capsule. TST was abnormal in 7/13 patients (sensitivity 54%) and DTI was abnormal in 3/12 (sensitivity 25%). Combining TST and DTI disclosed abnormalities in 8/11 patients (sensitivity 73%). TST confirmed UMN degeneration in one of every 2.25 patient in the diagnostic categories lower than 'probable' ALS. Using results from TST as a criterion for UMN degeneration, four patients in diagnostic categories lower than 'probable' ALS and without clinical signs of UMN degeneration in the cervical region increased in diagnostic category. Our findings indicate that TST has a significant diagnostic value as an early objective marker of UMN degeneration in ALS, while the value of DTI analysis seems limited.
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Affiliation(s)
- Jasna Furtula
- Department of Clinical Neurophysiology, Aarhus University Hospital, Noerrebrogade 44, Building 10, Parterre, 8000, Aarhus C, Denmark.
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Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques. Radiol Res Pract 2013; 2013:780916. [PMID: 24251037 PMCID: PMC3819952 DOI: 10.1155/2013/780916] [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: 04/29/2013] [Revised: 07/17/2013] [Accepted: 08/07/2013] [Indexed: 11/17/2022] Open
Abstract
Diffusion tensor imaging (DTI) data has traditionally been displayed as a grayscale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such asVmaxmaps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular nonstereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuroradiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuroradiologists favoredVmaxmaps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated thatVmaxbased display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data.
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Michelson G, Engelhorn T, Wärntges S, El Rafei A, Hornegger J, Doerfler A. DTI parameters of axonal integrity and demyelination of the optic radiation correlate with glaucoma indices. Graefes Arch Clin Exp Ophthalmol 2012; 251:243-53. [PMID: 22366916 DOI: 10.1007/s00417-011-1887-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/01/2011] [Accepted: 11/25/2011] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND In glaucoma, damage of retinal ganglion cells may continue to the linked optic radiations. This study investigates the correlation of glaucoma severity indicators with parameters of axonal and myelin integrity of the optic radiations. METHODS In this observational case-control study, 13 patients with normal-tension glaucoma, 13 patients with primary open-angle glaucoma, and seven control subjects (mean age, 57.6 ± 12.5 years) were randomly selected for diffusion tensor imaging (DTI) of the optic radiations. The results of the frequency doubling test (FDT) and the HRT-based linear discriminant functions of Burk (BLDF) and Mikelberg (MLDF) were correlated with the mean of the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and radial diffusivity (RD) of the optic radiations. Multiple correlation analysis, corrected for age, stage of cerebral microangiopathy, diagnosis group, and gender was conducted at increasing thresholds of linear anisotropy (C(L)) to reduce mismeasurements because of complex fiber situations. RESULTS The best correlations were found for BLDF with FA at C(L) threshold 0.3 (0.594, p = 0.001), with ADC at C(L) 0.4 (-0.511, p = 0.005), and with RD at C(L) 0.4 (-0.585, p = 0.001). MLDF correlated with FA at C(L) 0.4 (0.393, p = 0.035). The FDT score correlated with FA at C(L) 0 (-0.491, p = 0.007) and with RD at C(L) 0 (-0.375, p = 0.045). CONCLUSIONS In glaucoma, DTI-derived parameters of the axonal integrity (FA, ADC) and demyelination (RD) of the optic radiation are linked to HRT-based indices of glaucoma severity and to impairment of the spatial-temporal contrast sensitivity.
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Affiliation(s)
- Georg Michelson
- Department of Ophthalmology, University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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Karlsgodt KH, Jacobson SC, Seal M, Fusar-Poli P. The relationship of developmental changes in white matter to the onset of psychosis. Curr Pharm Des 2012; 18:422-33. [PMID: 22239573 PMCID: PMC7130450 DOI: 10.2174/138161212799316073] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/17/2011] [Indexed: 12/17/2022]
Abstract
Schizophrenia is a disorder with a pronounced developmental component. Accordingly, there is a growing interest in characterizing developmental changes in the period leading up to disease onset, in an effort to develop effective preventative interventions. One of the ongoing neurodevelopmental changes known to occur in the late adolescent period that often overlaps with the prodromal phase and time of onset is white matter development and myelination. In this critical review, a disruption in the normal trajectory of white matter development could potentially play an important role in the onset of psychosis. We seek to summarize the existing state of research on white matter development in prodromal subjects, with a particular focus on diffusion tensor imaging (DTI) measures. First, we describe the physiological basis of developmental white matter changes and myelination. Next, we characterize the pattern of white matter changes associated with typical development across adolescence as measured with DTI. Then, we discuss white matter changes observed in adult patients with schizophrenia and in individuals seen in genetic and clinical high risk states. Finally, we discuss the implications of these findings for future research directions and for potential therapeutic interventions.
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Affiliation(s)
- Katherine H Karlsgodt
- Semel Institute for Neuroscience and Behavior, University of California, Los Angeles, CA, USA.
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Yin X, Han Y, Ge H, Xu W, Huang R, Zhang D, Xu J, Fan L, Pang Z, Liu S. Inferior frontal white matter asymmetry correlates with executive control of attention. Hum Brain Mapp 2011; 34:796-813. [PMID: 22110013 DOI: 10.1002/hbm.21477] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 08/11/2011] [Accepted: 09/02/2011] [Indexed: 11/08/2022] Open
Abstract
White matter (WM) asymmetries of the human brain have been well documented using diffusion tensor imaging (DTI). However, the relationship between WM asymmetry pattern and cognitive performance is poorly understood. By means of tract-based spatial statistics (TBSS) and voxel-based analyses of whole brain, this study examined the WM asymmetries and the correlations between WM integrity/asymmetries and three distinct components of attention, namely alerting, orienting, and executive control (EC), which were assessed by attention network test (ANT). We revealed a number of WM anisotropy asymmetries, including leftward asymmetry of cingulum, corticospinal tract and cerebral peduncle, rightward asymmetry of internal capsule, superior longitudinal fasciculus and posterior corona radiata, as well as heterogeneous asymmetries in anterior corpus callosum and anterior corona radiata (ACR). Moreover, specific correlation was found between asymmetric pattern of inferior frontal ACR and EC performance. Additionally, this study also proposed that there were no significant relationships of WM anisotropy asymmetries to alerting and orienting functions. Further clusters of interest analyses and probabilistic fiber tracking validated our findings. In conclusion, there are a number of differences in WM integrity between human brain hemispheres. Specially, the anisotropy asymmetry in inferior frontal ACR plays a crucial role in EC function. Our finding is supportive of the functional studies of inferior frontal regions and in keeping with the theory of the brain lateralization on human ventral attention system.
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Affiliation(s)
- Xuntao Yin
- Research Center for Sectional and Imaging Anatomy, Shandong University School of Medicine, Jinan, Shandong, China
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Teepker M, Menzler K, Belke M, Heverhagen JT, Voelker M, Mylius V, Oertel WH, Rosenow F, Knake S. Diffusion tensor imaging in episodic cluster headache. Headache 2011; 52:274-82. [PMID: 22082475 DOI: 10.1111/j.1526-4610.2011.02000.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cluster headache (CH) is a rare headache disorder with severe unilateral headache bouts and autonomic symptoms. The pathophysiology of CH is not completely understood. Using a voxel-based morphometric paradigm or functional imaging, a key role of the hypothalamus and the pain matrix could be demonstrated during CH episodes. However, there are no diffusion tensor imaging (DTI) data investigating the white matter microstructure of the brain in patients with CH. Therefore, we used DTI to delineate microstructural changes in patients with CH in a headache-free state. METHODS Seven male patients with episodic CH and 7 healthy subjects were included and examined with a routine 1.5 T magnetic resonance imaging scanner. Whole-head DTI scans measuring fractional anisotropy were analyzed without a priori hypotheses using track-based spatial statistics. RESULTS We found significant microstructural brain tissue changes bilaterally in the white matter of the brainstem, the frontal lobe, the temporal lobe, the occipital lobe, the internal capsule, and on the right side of thalamus and cerebellum. There were further lesions in the basal frontal lobe that were part of the olfactory system. Alterations of fractional anisotropy in the brainstem might indicate changes of the medial lemniscus and central sympathetic pathways. CONCLUSIONS Patients with episodic CH have microstructural brain changes in regions that belong to the pain matrix. Furthermore, we were able to detect structural changes suggesting an involvement of the olfactory system as well as lesions in the brainstem indicating an involvement of trigeminal and sympathetic systems.
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Affiliation(s)
- Michael Teepker
- Department of Neurology, Philipps-University of Marburg, Marburg, Germany
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Kitamura S, Morikawa M, Kiuchi K, Taoka T, Fukusumi M, Kichikawa K, Kishimoto T. Asymmetry, sex differences and age-related changes in the white matter in the healthy elderly: a tract-based study. BMC Res Notes 2011; 4:378. [PMID: 21970546 PMCID: PMC3205060 DOI: 10.1186/1756-0500-4-378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 10/04/2011] [Indexed: 11/10/2022] Open
Abstract
Background Hemispherical asymmetry, sex differences and age-related changes have been reported for the human brain. Meanwhile it was still unclear the presence of the asymmetry or sex differences in the human brain occurred whether as a normal development or as consequences of any pathological changes. The aim of this study was to investigate hemispherical asymmetry, sex differences and age-related changes by using a tract-based analysis in the nerve bundles. Methods 40 healthy elderly subjects underwent magnetic resonance diffusion tensor imaging, and we calculated fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the major white matter bundles. Results We identified hemispherical asymmetry in the ADC values for the cingulate fasciculus in the total subject set and in males, and a sex difference in the FA values for the right uncinate fasciculus. For age-related changes, we demonstrated a significant increase in ADC values with advancing age in the right cingulum, left temporal white matter, and a significant decrease in FA values in the right superior longitudinal fasciculus. Conclusion In this study, we found hemispherical asymmetry, sex differences and age-related changes in particular regions of the white matter in the healthy elderly. Our results suggest considering these differences can be important in imaging studies.
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Affiliation(s)
- Soichiro Kitamura
- Department of Psychiatry, Nara Medical University, Kashihara, Japan.
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A framework for voxel-based morphometric analysis of the optic radiation using diffusion tensor imaging in glaucoma. Magn Reson Imaging 2011; 29:1076-87. [DOI: 10.1016/j.mri.2011.02.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 02/09/2011] [Accepted: 02/20/2011] [Indexed: 11/22/2022]
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Karlsgodt KH, Bachman P, Winkler AM, Bearden CE, Glahn DC. Genetic influence on the working memory circuitry: behavior, structure, function and extensions to illness. Behav Brain Res 2011; 225:610-22. [PMID: 21878355 DOI: 10.1016/j.bbr.2011.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 10/17/2022]
Abstract
Working memory is a highly heritable complex cognitive trait that is critical for a number of higher-level functions. However, the neural substrates of this behavioral phenotype are intricate and it is unknown through what precise biological mechanism variation in working memory is transmitted. In this review we explore different functional and structural components of the working memory circuitry, and the degree to which each of them is contributed to by genetic factors. Specifically, we consider dopaminergic function, glutamatergic function, white matter integrity and gray matter structure all of which provide potential mechanisms for the inheritance of working memory deficits. In addition to discussing the overall heritability of these measures we also address specific genes that may play a role. Each of these heritable components has the potential to uniquely contribute to the working memory deficits observed in genetic disorders, including 22q deletion syndrome, fragile X syndrome, phenylketonuria (PKU), and schizophrenia. By observing the individual contributions of disruptions in different components of the working memory circuitry to behavioral performance, we highlight the concept that there may be many routes to a working memory deficit; even though the same cognitive measure may be a valid endophenotype across different disorders, the underlying cause of, and treatment for, the deficit may differ. This has implications for our understanding of the transmission of working memory deficits in both healthy and disordered populations.
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Affiliation(s)
- Katherine H Karlsgodt
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
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Westerhausen R, Kompus K, Dramsdahl M, Falkenberg LE, Grüner R, Hjelmervik H, Specht K, Plessen K, Hugdahl K. A critical re-examination of sexual dimorphism in the corpus callosum microstructure. Neuroimage 2011; 56:874-80. [DOI: 10.1016/j.neuroimage.2011.03.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 11/24/2022] Open
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Taylor PA, Biswal B. Geometric analysis of the b-dependent effects of Rician signal noise on diffusion tensor imaging estimates and determining an optimal b value. Magn Reson Imaging 2011; 29:777-88. [PMID: 21550747 DOI: 10.1016/j.mri.2011.02.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 11/25/2022]
Abstract
The optimal diffusion weighting (DW) factor, b, for use in diffusion tensor imaging (DTI) studies remains uncertain. In this study, the geometric relations of DW quantities are examined, in particular, the effects of Rician noise in the measured magnetic resonance signal. This geometric analysis is used to make theoretical predictions for selecting a b value to reduce the influence of noise. It is shown that the optimal b value for DTI studies in healthy human parenchyma is approximately b=1200 s mm(-2), with a simple relation given as well for a given expected apparent diffusion coefficient. Monte-Carlo simulations on sets of realistic DTI measures are then performed, verifying the optimal DW for minimizing estimate errors. The effects of noise on various DTI parameters such as anisotropy indices (fractional anisotropy and scaled relative anisotropy), mean diffusivity, radial diffusivity, eigenvalues and the direction of the first eigenvector are investigated as well.
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Affiliation(s)
- Paul A Taylor
- Department of Radiology, UMDNJ-New Jersey Medical School, Newark, NJ, USA.
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Menzler K, Belke M, Wehrmann E, Krakow K, Lengler U, Jansen A, Hamer HM, Oertel WH, Rosenow F, Knake S. Men and women are different: diffusion tensor imaging reveals sexual dimorphism in the microstructure of the thalamus, corpus callosum and cingulum. Neuroimage 2010; 54:2557-62. [PMID: 21087671 DOI: 10.1016/j.neuroimage.2010.11.029] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 11/04/2010] [Accepted: 11/08/2010] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION Numerous magnetic resonance imaging (MRI) studies have addressed the question of morphological differences of the brain of men and women, reporting conflicting results regarding brain size and the ratio of gray and white matter. In the present study, we used diffusion tensor imaging (DTI) to delineate sex differences of brain white matter. METHODS We investigated brain microstructure in 25 male and 25 female healthy subjects using a 3T MRI scanner. Whole-head DTI scans were analyzed without a-priori hypothesis using Tract-Based Spatial Statistics (TBSS) calculating maps of fractional anisotropy (FA), radial diffusivity (RD, a potential marker of glial alteration and changes in myelination) and axial diffusivity (AD, a potential marker of axonal changes). RESULTS DTI revealed regional microstructural differences between the brains of male and female subjects. Those were prominent in the thalamus, corpus callosum and cingulum. Men showed significantly (p<0.0001) higher values of fractional anisotropy and lower radial diffusivity in these areas, suggesting that the observed differences are mainly due to differences in myelination. DISCUSSION As a novel finding we showed widespread differences in thalamic microstructure that have not been described previously. Additionally, the present study confirmed earlier DTI studies focusing on sexual dimorphism in the corpus callosum and cingulum. All changes appear to be based on differences in myelination. The sex differences in thalamic microstructure call for further studies on the underlying cause and the behavioral correlates of this sexual dimorphism. Future DTI group studies may carefully control for gender to avoid confounding.
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Affiliation(s)
- K Menzler
- Philipps-University Marburg, Center of Brain Imaging, Department of Neurology, Marburg, Germany
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de Luis-García R, Westin CF, Alberola-López C. Gaussian mixtures on tensor fields for segmentation: applications to medical imaging. Comput Med Imaging Graph 2010; 35:16-30. [PMID: 20932717 DOI: 10.1016/j.compmedimag.2010.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 05/10/2010] [Accepted: 09/01/2010] [Indexed: 10/19/2022]
Abstract
In this paper, we introduce a new approach for tensor field segmentation based on the definition of mixtures of Gaussians on tensors as a statistical model. Working over the well-known Geodesic Active Regions segmentation framework, this scheme presents several interesting advantages. First, it yields a more flexible model than the use of a single Gaussian distribution, which enables the method to better adapt to the complexity of the data. Second, it can work directly on tensor-valued images or, through a parallel scheme that processes independently the intensity and the local structure tensor, on scalar textured images. Two different applications have been considered to show the suitability of the proposed method for medical imaging segmentation. First, we address DT-MRI segmentation on a dataset of 32 volumes, showing a successful segmentation of the corpus callosum and favourable comparisons with related approaches in the literature. Second, the segmentation of bones from hand radiographs is studied, and a complete automatic-semiautomatic approach has been developed that makes use of anatomical prior knowledge to produce accurate segmentation results.
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Affiliation(s)
- Rodrigo de Luis-García
- Laboratory of Mathematics in Imaging, Brigham and Women's Hospital, 1249 Boylston St., Boston, MA 02215, USA.
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Regional heterogeneity and age-related change in sub-regions of internal capsule evaluated by diffusion tensor imaging. Brain Res 2010; 1354:30-9. [DOI: 10.1016/j.brainres.2010.07.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 07/21/2010] [Accepted: 07/23/2010] [Indexed: 11/18/2022]
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Jolapara M, Patro SN, Kesavadas C, Saini J, Thomas B, Gupta AK, Bodhey N, Radhakrishnan VV. Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases. Neuroradiology 2010; 53:63-8. [PMID: 20809287 DOI: 10.1007/s00234-010-0761-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 08/12/2010] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Diffusion weighted imaging and diffusion tensor imaging (DTI) give information about the amount and directionality of water diffusion occurring in a given tissue. Here we study the role of diffusion tensor metrics including fractional anisotropy (FA) and spherical anisotropy (CS) in preoperative grading of diffusely infiltrating astrocytomas. METHODS We performed DTI in 38 patients with pathologically proven diffusely infiltrating astrocytomas, who were classified into two groups, i.e., 15 patients with high-grade astrocytoma (HGAs, WHO grade III and IV) and 23 patients with low-grade astrocytoma (LGAs, WHO grade II). We measured maximum FA and minimum CS values in all cases from tumor. Histopathological diagnosis was established in all cases. RESULTS The mean maximum FA values were higher in HGA (0.583 ± 0.104) than LGA (0.295 ± 0.058), while mean minimum CS values were lower in HGA (0.42 ± 0.121) than LGA (0.722 ± 0.061). The difference in the diffusion tensor indices between HGA and LGA was found to be statistically significant with P value of <0.001. Keeping cutoff FA value of 0.4, all HGAs showed higher maximum FA values, and all LGAs showed lower maximum FA values. Also, all HGAs showed minimum CS values less than a cutoff value of 0.6, and all LGAs showed minimum CS values higher than 0.6. CONCLUSION Diffusion tensor metrics such as maximum FA and minimum CS can help to differentiate HGA from LGA.
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Affiliation(s)
- Milan Jolapara
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
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Mamah D, Conturo TE, Harms MP, Akbudak E, Wang L, McMichael AR, Gado MH, Barch DM, Csernansky JG. Anterior thalamic radiation integrity in schizophrenia: a diffusion-tensor imaging study. Psychiatry Res 2010; 183:144-50. [PMID: 20619618 PMCID: PMC3887223 DOI: 10.1016/j.pscychresns.2010.04.013] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 03/30/2010] [Accepted: 04/26/2010] [Indexed: 11/26/2022]
Abstract
The anterior limb of the internal capsule (ALIC) is a white matter structure, the medial portion of which includes the anterior thalamic radiation (ATR) carrying nerve fibers between thalamus and prefrontal cortex. ATR abnormalities have a possible link with cognitive abnormalities and negative symptoms in schizophrenia. We aimed to study the fiber integrity of the ATR more selectively by isolating the medial portion of the ALIC using region-of-interest based methodology. Diffusion-tensor imaging was used to measure the anisotropy of total ALIC (tALIC) and medial ALIC (mALIC) in 39 schizophrenia and 33 control participants, matched for age/gender/handedness. Relationships between anisotropy, psychopathology, and cognitive performance were analyzed. Compared with controls, schizophrenia participants had 4.55% lower anisotropy in right tALIC, and 5.38% lower anisotropy in right mALIC. There were no significant group anisotropy differences on the left. Significant correlations were observed between right ALIC integrity and relevant domains of cognitive function (e.g., executive function, working memory). Our study suggests an asymmetric microstructural change in ALIC in schizophrenia involving the right side, which is only minimally stronger in mALIC, and which correlates with cognitive impairment. Microstructural changes in the ALIC may be linked to cognitive dysfunction in schizophrenia.
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Affiliation(s)
- Daniel Mamah
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, United States.
| | - Thomas E. Conturo
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Michael P. Harms
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Erbil Akbudak
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Lei Wang
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Amanda R. McMichael
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Mokhtar H. Gado
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Deanna M. Barch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri,Department of Radiology, Washington University School of Medicine, St. Louis, Missouri,Department of Psychology, Washington University School of Medicine, St. Louis, Missouri
| | - John G. Csernansky
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Prados F, Boada I, Prats-Galino A, Martín-Fernández JA, Feixas M, Blasco G, Puig J, Pedraza S. Analysis of new diffusion tensor imaging anisotropy measures in the three-phase plot. J Magn Reson Imaging 2010; 31:1435-44. [DOI: 10.1002/jmri.22178] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Hasan KM, Kamali A, Abid H, Kramer LA, Fletcher JM, Ewing-Cobbs L. Quantification of the spatiotemporal microstructural organization of the human brain association, projection and commissural pathways across the lifespan using diffusion tensor tractography. Brain Struct Funct 2010; 214:361-73. [PMID: 20127357 DOI: 10.1007/s00429-009-0238-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Accepted: 12/21/2009] [Indexed: 01/09/2023]
Abstract
Using diffusion tensor tractography, we quantified the microstructural changes in the association, projection, and commissural compact white matter pathways of the human brain over the lifespan in a cohort of healthy right-handed children and adults aged 6-68 years. In both males and females, the diffusion tensor radial diffusivity of the bilateral arcuate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, corticospinal, somatosensory tracts, and the corpus callosum followed a U-curve with advancing age; fractional anisotropy in the same pathways followed an inverted U-curve. Our study provides useful baseline data for the interpretation of data collected from patients.
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Affiliation(s)
- Khader M Hasan
- Department of Diagnostic and Interventional Imaging, University of Texas Medical School at Houston-Medical School, Houston, TX 77030, USA.
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White matter plasticity in the corticospinal tract of musicians: A diffusion tensor imaging study. Neuroimage 2009; 46:600-7. [DOI: 10.1016/j.neuroimage.2009.02.025] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 12/15/2008] [Accepted: 02/16/2009] [Indexed: 12/13/2022] Open
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Santhosh K, Thomas B, Radhakrishnan VV, Saini J, Kesavadas C, Gupta AK, Kapilamoorthy TR, Nair SN. Diffusion tensor and tensor metrics imaging in intracranial epidermoid cysts. J Magn Reson Imaging 2009; 29:967-70. [PMID: 19306444 DOI: 10.1002/jmri.21686] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) in characterizing the structural pathology of epidermoid cysts. DTI gives information about the tissue structure; a high fractional anisotropy (FA) indicates a highly structured orientation of the tissue, fibers, or white matter tracts. Based on the tensor rank, a set of three metrics has been described that can be used to measure the directional dependence of diffusion: linear anisotropy (CL), planar anisotropy (CP), and spherical anisotropy (CS). DTM takes into account the shape of diffusion anisotropy and hence may provide better insight into the orientation of structures than FA. MATERIALS AND METHODS DTI was performed in three patients with epidermoid cysts. FA, directionally-averaged mean diffusivity (Dav), exponential apparent diffusion coefficient (eADC), and DTM, such as CL, CP, and CS, were measured from the tumor core as well as from the normal-appearing white matter. Histopathological correlation was obtained. RESULTS Epidermoid cysts showed high FA with Dav values similar to that of normal white matter. eADC maps did not show any restriction of diffusion. FA values were high, but not as high as that for the white matter. CP values were higher and CL values were lower than those obtained for the white matter in various regions. CONCLUSION High CP values suggest preferential diffusion of water molecules along a two-dimensional geometry, which could be attributed to the well-structured orientation of keratin filaments and flakes within the tumor as demonstrated by histopathology. Advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts.
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Affiliation(s)
- Kannath Santhosh
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Science and Technology, Trivandrum, Kerala, India
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Using Perturbation theory to reduce noise in diffusion tensor fields. Med Image Anal 2009; 13:580-97. [PMID: 19540791 DOI: 10.1016/j.media.2009.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 04/23/2009] [Accepted: 05/06/2009] [Indexed: 11/22/2022]
Abstract
We propose the use of Perturbation theory to reduce noise in Diffusion Tensor (DT) fields. Diffusion Tensor Imaging (DTI) encodes the diffusion of water molecules along different spatial directions in a positive definite, 3 x 3 symmetric tensor. Eigenvectors and eigenvalues of DTs allow the in vivo visualization and quantitative analysis of white matter fiber bundles across the brain. The validity and reliability of these analyses are limited, however, by the low spatial resolution and low Signal-to-Noise Ratio (SNR) in DTI datasets. Our procedures can be applied to improve the validity and reliability of these quantitative analyses by reducing noise in the tensor fields. We model a tensor field as a three-dimensional Markov Random Field and then compute the likelihood and the prior terms of this model using Perturbation theory. The prior term constrains the tensor field to be smooth, whereas the likelihood term constrains the smoothed tensor field to be similar to the original field. Thus, the proposed method generates a smoothed field that is close in structure to the original tensor field. We evaluate the performance of our method both visually and quantitatively using synthetic and real-world datasets. We quantitatively assess the performance of our method by computing the SNR for eigenvalues and the coherence measures for eigenvectors of DTs across tensor fields. In addition, we quantitatively compare the performance of our procedures with the performance of one method that uses a Riemannian distance to compute the similarity between two tensors, and with another method that reduces noise in tensor fields by anisotropically filtering the diffusion weighted images that are used to estimate diffusion tensors. These experiments demonstrate that our method significantly increases the coherence of the eigenvectors and the SNR of the eigenvalues, while simultaneously preserving the fine structure and boundaries between homogeneous regions, in the smoothed tensor field.
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Minnerop M, Specht K, Ruhlmann J, Grothe C, Wüllner U, Klockgether T. In vivo voxel-based relaxometry in amyotrophic lateral sclerosis. J Neurol 2009; 256:28-34. [DOI: 10.1007/s00415-009-0947-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2007] [Revised: 03/04/2008] [Accepted: 03/26/2008] [Indexed: 11/30/2022]
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Sherbondy AJ, Dougherty RF, Napel S, Wandell BA. Identifying the human optic radiation using diffusion imaging and fiber tractography. J Vis 2008; 8:12.1-11. [PMID: 19146354 DOI: 10.1167/8.10.12] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 08/15/2008] [Indexed: 11/24/2022] Open
Abstract
Measuring the properties of the white matter pathways from retina to cortex in the living human brain will have many uses for understanding visual performance and guiding clinical treatment. For example, identifying the Meyer's loop portion of the optic radiation (OR) has clinical significance because of the large number of temporal lobe resections. We use diffusion tensor imaging and fiber tractography (DTI-FT) to identify the most likely pathway between the lateral geniculate nucleus (LGN) and the calcarine sulcus in sixteen hemispheres of eight healthy volunteers. Quantitative population comparisons between DTI-FT estimates and published postmortem dissections match with a spatial precision of about 1 mm. The OR can be divided into three bundles that are segmented based on the direction of the fibers as they leave the LGN: Meyer's loop, central, and direct. The longitudinal and radial diffusivities of the three bundles do not differ within the measurement noise; there is a small difference in the radial diffusivity between the right and left hemispheres. We find that the anterior tip of Meyer's loop is 28 +/- 3 mm posterior to the temporal pole, and the population range is 1 cm. Hence, it is important to identify the location of this bundle in individual subjects or patients.
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Affiliation(s)
- Anthony J Sherbondy
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
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Wilde EA, McCauley SR, Chu Z, Hunter JV, Bigler ED, Yallampalli R, Wang ZJ, Hanten G, Li X, Ramos MA, Sabir SH, Vasquez AC, Menefee D, Levin HS. Diffusion tensor imaging of hemispheric asymmetries in the developing brain. J Clin Exp Neuropsychol 2008; 31:205-18. [PMID: 19052951 DOI: 10.1080/13803390802098118] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Diffusion tensor imaging (DTI) was performed in 39 right-handed children to examine structural hemispheric differences and the impact of age, socioeconomic status, and sex on these differences. Apparent diffusion coefficient (ADC) values were smaller in the left than in the right temporal, prefrontal, anterior internal capsular and the thalamic regions, and fractional anisotropy (FA) values were larger in the left than in the right internal capsule, thalamus, and cingulate. Significant region-by-sex interactions disclosed that the relation of DTI asymmetries to performance depended on sex including the relation of temporal lobes to reading comprehension and the relation of frontal lobes to solving applied mathematical problems.
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Affiliation(s)
- Elisabeth A Wilde
- Physical Medicine and Rehabilitation Alliance of Baylor College of Medicine and the University of Texas-Houston Medical School, Houston, TX 77030, USA.
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Jolapara M, Kesavadas C, Radhakrishnan VV, Saini J, Patro SN, Gupta AK, Kapilamoorthy TR, Bodhey N. Diffusion tensor mode in imaging of intracranial epidermoid cysts: one step ahead of fractional anisotropy. Neuroradiology 2008; 51:123-9. [PMID: 18839162 DOI: 10.1007/s00234-008-0464-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 09/15/2008] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The signal characteristics of an epidermoid on T2-weighted imaging have been attributed to the presence of increased water content within the tumor. In this study, we explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) in knowing the microstructural anatomy of epidermoid cysts. MATERIALS AND METHODS DTI was performed in ten patients with epidermoid cysts. Directionally averaged mean diffusivity (D(av)), exponential diffusion, and DTM-like fractional anisotropy (FA), diffusion tensor mode (mode), linear (CL), planar (CP), and spherical (CS) anisotropy were measured from the tumor as well as from the normal-looking white matter. RESULTS Epidermoid cysts showed high FA. However, D(av) and exponential diffusion values did not show any restriction of diffusion. Diffusion tensor mode values were near -1, and CP values were high within the tumor. This suggested preferential diffusion of water molecules along a two-dimensional geometry (plane) in epidermoid cysts, which could be attributed to the parallel-layered arrangement of keratin filaments and flakes within these tumors. CONCLUSION Thus, advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts.
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Affiliation(s)
- Milan Jolapara
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695011, India
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Developmental disruptions in neural connectivity in the pathophysiology of schizophrenia. Dev Psychopathol 2008; 20:1297-327. [DOI: 10.1017/s095457940800062x] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractSchizophrenia has been thought of as a disorder of reduced functional and structural connectivity. Recent advances in neuroimaging techniques such as functional magnetic resonance imaging, structural magnetic resonance imaging, diffusion tensor imaging, and small animal imaging have advanced our ability to investigate this hypothesis. Moreover, the power of longitudinal designs possible with these noninvasive techniques enable the study of not just how connectivity is disrupted in schizophrenia, but when this disruption emerges during development. This article reviews genetic and neurodevelopmental influences on structural and functional connectivity in human populations with or at risk for schizophrenia and in animal models of the disorder. We conclude that the weight of evidence across these diverse lines of inquiry points to a developmental disruption of neural connectivity in schizophrenia and that this disrupted connectivity likely involves susceptibility genes that affect processes involved in establishing intra- and interregional connectivity.
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Haris M, Kumar S, Raj MK, Das KJM, Sapru S, Behari S, Rathore RKS, Narayana PA, Gupta RK. Serial diffusion tensor imaging to characterize radiation-induced changes in normal-appearing white matter following radiotherapy in patients with adult low-grade gliomas. ACTA ACUST UNITED AC 2008; 26:140-50. [PMID: 18683569 DOI: 10.1007/s11604-007-0209-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE The aim of this study was to ascertain whether diffusion tensor imaging (DTI) metrics fractional anisotropy (FA), mean diffusivity (MD), linear case (CL), planar case (CP), spherical case (CS)-can characterize a threshold dose and temporal evolution of changes in normal-appearing white matter (NAWM) of adults with low-grade gliomas (LGGs) treated with radiation therapy (RT). METHODS AND MATERIALS Conventional and DTI imaging were performed before RT in 5 patients and subsequently, on average, at 3 months (n = 5), 8 months (n = 3), and 14 months (n = 5) following RT for a total of 18 examinations. Isodose distribution at 5-Gy intervals were visualized in all the slices of fluid attenuated inversion recovery (FLAIR) and the corresponding DTI images without diffusion sensitization (b0DTI). The latter were exported for relative quantitative analysis. RESULTS Compared to pre-RT values, FA and CL decreased, whereas CS increased at 3 and 8 months and recovered partially at 14 months for the dose bins >55 Gy and 50-55 Gy. For the 45 50 Gy bin, the FA and CL decreased with an increase in CS at 3 months; no further change was seen at 8 or 14 months. For the >55 Gy and 50-55 Gy bins, CP decreased and MD increased at 3 months and returned to baseline at 8 months following RT. CONCLUSION Radiation-induced changes in NAWM can be detected at 3 months after RT, with changes in FA, CL, and CS (but not CP or MD) values seen at a threshold dose of 45-50 Gy. A partial recovery was evident by 14 months to regions that received doses of 50-55 Gy and >55 Gy, thus providing an objective measure of radiation effect on NAWM.
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Affiliation(s)
- Mohammad Haris
- Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow 226014, India
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Mädler B, Drabycz SA, Kolind SH, Whittall KP, MacKay AL. Is diffusion anisotropy an accurate monitor of myelination? Magn Reson Imaging 2008; 26:874-88. [PMID: 18524521 DOI: 10.1016/j.mri.2008.01.047] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 01/14/2008] [Indexed: 11/16/2022]
Affiliation(s)
- Burkhard Mädler
- Department of Physics and Astronomy, University of British Columbia Hospital, Vancouver BC, Canada.
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Gupta RK, Haris M, Husain N, Saksena S, Husain M, Rathore RKS. DTI derived indices correlate with immunohistochemistry obtained matrix metalloproteinase (MMP-9) expression in cellular fraction of brain tuberculoma. J Neurol Sci 2008; 275:78-85. [PMID: 18757066 DOI: 10.1016/j.jns.2008.07.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2008] [Revised: 06/24/2008] [Accepted: 07/22/2008] [Indexed: 01/19/2023]
Abstract
We performed in vivo diffusion tensor imaging (DTI) in a total of 33 patients with brain tuberculomas (BT). Thirteen of them had surgical excision of the lesion as it was clinically indicated, and in these samples matrix metalloproteinase-9 (MMP-9) expression was quantified. We correlated the results of DTI indices like fractional anisotropy (FA), mean diffusivity (MD), linear anisotropy (CL), planar anisotropy (CP) and spherical anisotropy (CS) with MMP-9 expression. In addition, the remaining 20 patients had serial DTI studies while on specific anti-tuberculous drug therapy and DTI indices in these patients were quantified. The FA, CL and CP significantly decreased while MD and CS significantly increased in BT compared to normal white matter. The FA, CL and CP showed negative correlation with MMP-9 while CS correlated positively. In serial follow-up studies in 20 patients FA, CL and CP showed significant increase while CS decreased significantly over time. We conclude that DTI indices show strong correlation with MMP-9 and these may be used as a surrogate marker of MMP-9 expression in BT. In addition, these indices may be of value in assessing the therapeutic response in patients with BT who are treated only with specific anti-tuberculous drugs.
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Affiliation(s)
- Rakesh K Gupta
- Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India.
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Correia MM, Carpenter TA, Williams GB. Looking for the optimal DTI acquisition scheme given a maximum scan time: are more b-values a waste of time? Magn Reson Imaging 2008; 27:163-75. [PMID: 18687552 DOI: 10.1016/j.mri.2008.06.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 05/30/2008] [Accepted: 06/21/2008] [Indexed: 10/21/2022]
Abstract
In this study we used simulated data to investigate how valuable the use of multiple b-values is, in terms of improving the accuracy and reproducibility of Diffusion Tensor Imaging (DTI) results. Our results show that the systematic bias of the estimated scalar diffusion parameters [apparent diffusion coefficient and fractional anisotropy (FA)] - due to the Rician distribution of magnetic resonance noise - can be minimized by increasing the number of b-values and not by increasing the number of sampling directions. In addition, the use of more than one b-value accounts better for the wide range of diffusivities found in the human brain by bringing closer together the FA estimates for fibres with different mean diffusivities. It is also shown that while for tractography studies we should use as many sampling directions as allowed by scan time limitations, for follow-up, intersubject or multicenter studies, the use of more than one b-value will improve the accuracy of the scalar diffusion parameters, as long as the minimum number of directions required for robust estimation of each parameter is still used.
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Sherbondy AJ, Dougherty RF, Ben-Shachar M, Napel S, Wandell BA. ConTrack: finding the most likely pathways between brain regions using diffusion tractography. J Vis 2008; 8:15.1-16. [PMID: 18831651 PMCID: PMC2696074 DOI: 10.1167/8.9.15] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 03/31/2008] [Indexed: 11/24/2022] Open
Abstract
Magnetic resonance diffusion-weighted imaging coupled with fiber tractography (DFT) is the only non-invasive method for measuring white matter pathways in the living human brain. DFT is often used to discover new pathways. But there are also many applications, particularly in visual neuroscience, in which we are confident that two brain regions are connected, and we wish to find the most likely pathway forming the connection. In several cases, current DFT algorithms fail to find these candidate pathways. To overcome this limitation, we have developed a probabilistic DFT algorithm (ConTrack) that identifies the most likely pathways between two regions. We introduce the algorithm in three parts: a sampler to generate a large set of potential pathways, a scoring algorithm that measures the likelihood of a pathway, and an inferential step to identify the most likely pathways connecting two regions. In a series of experiments using human data, we show that ConTrack estimates known pathways at positions that are consistent with those found using a high quality deterministic algorithm. Further we show that separating sampling and scoring enables ConTrack to identify valid pathways, known to exist, that are missed by other deterministic and probabilistic DFT algorithms.
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Affiliation(s)
- Anthony J Sherbondy
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
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Hasan KM, Kamali A, Kramer LA, Papnicolaou AC, Fletcher JM, Ewing-Cobbs L. Diffusion tensor quantification of the human midsagittal corpus callosum subdivisions across the lifespan. Brain Res 2008; 1227:52-67. [PMID: 18598682 DOI: 10.1016/j.brainres.2008.06.030] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/08/2008] [Accepted: 06/10/2008] [Indexed: 11/19/2022]
Abstract
The midsagittal corpus callosum (CC) cross-sectional area subdivisions have been used as early and sensitive markers of human brain white matter connectivity, development, natural aging and disease. Despite the simplicity and conspicuity of the appearance of the CC on anatomical magnetic resonance imaging (MRI), the published quantitative MRI literature on its regional sex and age trajectories are contradictory. The availability of noninvasive quantitative methods to assess the CC regions across the human lifespan would help clarify its contribution to behavior and cognition. In this report, we extended the utility of a recently described semi-automated diffusion tensor imaging (DTI) tissue segmentation method to utilize the high orientation contrast of the CC on DTI. Using optimized DTI methods on a cohort of 121 right-handed children and adults aged 6-68 years, we examined the CC areas and corresponding DTI metrics of the different functionally specialized sectors of the CC. Both the area and fractional anisotropy metrics followed inverted U-shaped curves, while the mean and radial diffusivities followed U-curves reflecting white matter progressive and regressive myelination dynamics that continue into young adulthood.
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Affiliation(s)
- Khader M Hasan
- Department of Diagnostic and Interventional Imaging, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 2.100, Houston, Texas 77030, USA.
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