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Arshad NH, Abu Hassan H, Omar NF, Zainudin Z. Quantifying myelin in neonates using magnetic resonance imaging: a systematic literature review. Clin Exp Pediatr 2024; 67:371-385. [PMID: 38062713 PMCID: PMC11298773 DOI: 10.3345/cep.2023.00514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/11/2023] [Accepted: 08/12/2023] [Indexed: 08/03/2024] Open
Abstract
This review aimed to assess the usefulness of various magnetic resonance imaging (MRI) techniques for the quantification of neonatal white matter myelination. The Scopus, PubMed, and Web of Science databases were searched to identify studies following the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement using quantitative MRI techniques to examine samples collected from neonates to quantify myelin. Twelve studies were ultimately included. The results demonstrated that in validation studies, relaxometry is the most frequently explored approach (83.33%), followed by magnetization transfer imaging (8.33%) and a new automatic segmentation technique (8.33%). Synthetic MRI is recommended for quantifying myelin in neonates because of several advantages that outweigh a few negligible limitations.
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Affiliation(s)
- Nabila Hanem Arshad
- Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
- Department of Radiology, Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia, Selangor, Malaysia
| | - Hasyma Abu Hassan
- Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Nur Farhayu Omar
- Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Zurina Zainudin
- Department of Paediatrics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
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2
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Lee JJ, Scheuren PS, Liu H, Loke RWJ, Laule C, Loucks CM, Kramer JLK. The myelin water imaging transcriptome: myelin water fraction regionally varies with oligodendrocyte-specific gene expression. Mol Brain 2024; 17:45. [PMID: 39044257 PMCID: PMC11264438 DOI: 10.1186/s13041-024-01115-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/19/2024] [Indexed: 07/25/2024] Open
Abstract
Identifying sensitive and specific measures that can quantify myelin are instrumental in characterizing microstructural changes in neurological conditions. Neuroimaging transcriptomics is emerging as a valuable technique in this regard, offering insights into the molecular basis of promising candidates for myelin quantification, such as myelin water fraction (MWF). We aimed to demonstrate the utility of neuroimaging transcriptomics by validating MWF as a myelin measure. We utilized data from a normative MWF brain atlas, comprised of 50 healthy subjects (mean age = 25 years, range = 17-42 years) scanned at 3 Tesla. Magnetic resonance imaging data included myelin water imaging to extract MWF and T1 anatomical scans for image registration and segmentation. We investigated the inter-regional distributions of gene expression data from the Allen Human Brain Atlas in conjunction with inter-regional MWF distribution patterns. Pearson correlations were used to identify genes with expression profiles mirroring MWF. The Single Cell Type Atlas from the Human Protein Atlas was leveraged to classify genes into gene sets with high cell type specificity, and a control gene set with low cell type specificity. Then, we compared the Pearson correlation coefficients for each gene set to determine if cell type-specific gene expression signatures correlate with MWF. Pearson correlation coefficients between MWF and gene expression for oligodendrocytes and adipocytes were significantly higher than for the control gene set, whereas correlations between MWF and inhibitory/excitatory neurons were significantly lower. Our approach in integrating transcriptomics with neuroimaging measures supports an emerging technique for understanding and validating MRI-derived markers such as MWF.
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Affiliation(s)
- Jaimie J Lee
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Paulina S Scheuren
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Hanwen Liu
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Ryan W J Loke
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Cornelia Laule
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Catrina M Loucks
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada
- Division of Translational Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
- BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - John L K Kramer
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada.
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3
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Faulkner ME, Gong Z, Guo A, Laporte JP, Bae J, Bouhrara M. Harnessing myelin water fraction as an imaging biomarker of human cerebral aging, neurodegenerative diseases, and risk factors influencing myelination: A review. J Neurochem 2024. [PMID: 38973579 DOI: 10.1111/jnc.16170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 07/09/2024]
Abstract
Myelin water fraction (MWF) imaging has emerged as a promising magnetic resonance imaging (MRI) biomarker for investigating brain function and composition. This comprehensive review synthesizes the current state of knowledge on MWF as a biomarker of human cerebral aging, neurodegenerative diseases, and risk factors influencing myelination. The databases used include Web of Science, Scopus, Science Direct, and PubMed. We begin with a brief discussion of the theoretical foundations of MWF imaging, including its basis in MR physics and the mathematical modeling underlying its calculation, with an overview of the most adopted MRI methods of MWF imaging. Next, we delve into the clinical and research applications that have been explored to date, highlighting its advantages and limitations. Finally, we explore the potential of MWF to serve as a predictive biomarker for neurological disorders and identify future research directions for optimizing MWF imaging protocols and interpreting MWF in various contexts. By harnessing the power of MWF imaging, we may gain new insights into brain health and disease across the human lifespan, ultimately informing novel diagnostic and therapeutic strategies.
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Affiliation(s)
- Mary E Faulkner
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Alex Guo
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - John P Laporte
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Jonghyun Bae
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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4
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Wiggermann V, Endmayr V, Hernández‐Torres E, Höftberger R, Kasprian G, Hametner S, Rauscher A. Quantitative magnetic resonance imaging reflects different levels of histologically determined myelin densities in multiple sclerosis, including remyelination in inactive multiple sclerosis lesions. Brain Pathol 2023; 33:e13150. [PMID: 36720269 PMCID: PMC10580011 DOI: 10.1111/bpa.13150] [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: 05/05/2022] [Accepted: 11/16/2022] [Indexed: 02/02/2023] Open
Abstract
Magnetic resonance imaging (MRI) of focal or diffuse myelin damage or remyelination may provide important insights into disease progression and potential treatment efficacy in multiple sclerosis (MS). We performed post-mortem MRI and histopathological myelin measurements in seven progressive MS cases to evaluate the ability of three myelin-sensitive MRI scans to distinguish different stages of MS pathology, particularly chronic demyelinated and remyelinated lesions. At 3 Tesla, we acquired two different myelin water imaging (MWI) scans and magnetisation transfer ratio (MTR) data. Histopathology included histochemical stainings for myelin phospholipids (LFB) and iron as well as immunohistochemistry for myelin proteolipid protein (PLP), CD68 (phagocytosing microglia/macrophages) and BCAS1 (remyelinating oligodendrocytes). Mixed-effects modelling determined which histopathological metric best predicted MWF and MTR in normal-appearing and diffusely abnormal white matter, active/inactive, inactive, remyelinated and ischemic lesions. Both MWI measures correlated well with each other and histology across regions, reflecting the different stages of MS pathology. MTR data showed a considerable influence of components other than myelin and a strong dependency on tissue storage duration. Both MRI and histology revealed increased myelin densities in inactive compared with active/inactive lesions. Chronic inactive lesions harboured single scattered myelin fibres indicative of low-level remyelination. Mixed-effects modelling showed that smaller differences between white matter areas were linked to PLP densities and only to a small extent confounded by iron. MWI reflects differences in myelin lipids and proteins across various levels of myelin densities encountered in MS, including low-level remyelination in chronic inactive lesions.
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Affiliation(s)
- Vanessa Wiggermann
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of PediatricsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Danish Research Centre for Magnetic ResonanceCopenhagen University Hospital Amager & HvidovreCopenhagenDenmark
| | - Verena Endmayr
- Division of Neuropathology and Neurochemistry, Department of NeurologyMedical University of ViennaViennaAustria
- Centre for Brain ResearchMedical University of ViennaViennaAustria
| | - Enedino Hernández‐Torres
- Danish Research Centre for Magnetic ResonanceCopenhagen University Hospital Amager & HvidovreCopenhagenDenmark
- Faculty of Medicine (Division Neurology)University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Romana Höftberger
- Division of Neuropathology and Neurochemistry, Department of NeurologyMedical University of ViennaViennaAustria
| | - Gregor Kasprian
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
| | - Simon Hametner
- Division of Neuropathology and Neurochemistry, Department of NeurologyMedical University of ViennaViennaAustria
- Centre for Brain ResearchMedical University of ViennaViennaAustria
| | - Alexander Rauscher
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of PediatricsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of RadiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- BC Children's Hospital Research InstituteUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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5
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Alsop DC, Ercan E, Girard OM, Mackay AL, Michal CA, Varma G, Vinogradov E, Duhamel G. Inhomogeneous magnetization transfer imaging: Concepts and directions for further development. NMR IN BIOMEDICINE 2023; 36:e4808. [PMID: 35916067 DOI: 10.1002/nbm.4808] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 05/23/2023]
Abstract
Off-resonance radio frequency irradiation can induce the ordering of proton spins in the dipolar fields of their neighbors, in molecules with restricted mobility. This dipolar order decays with a characteristic relaxation time, T1D , that is very different from the T1 and T2 relaxation of the nuclear alignment with the main magnetic field. Inhomogeneous magnetization transfer (ihMT) imaging is a refinement of magnetization transfer (MT) imaging that isolates the MT signal dependence on dipolar order relaxation times within motion-constrained molecules. Because T1D relaxation is a unique contrast mechanism, ihMT may enable improved characterization of tissue. Initial work has stressed the high correlation between ihMT signal and myelin density. Dipolar order relaxation appears to be much longer in membrane lipids than other molecules. Recent work has shown, however, that ihMT acquisitions may also be adjusted to emphasize different ranges of T1D . These newer approaches may be sensitive to other microstructural components of tissue. Here, we review the concepts and history of ihMT and outline the requirements for further development to realize its full potential.
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Affiliation(s)
- David C Alsop
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Ece Ercan
- MR Clinical Science, Philips, Best, The Netherlands
| | | | - Alex L Mackay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carl A Michal
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gopal Varma
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Elena Vinogradov
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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Stellingwerff MD, Pouwels PJW, Roosendaal SD, Barkhof F, van der Knaap MS. Quantitative MRI in leukodystrophies. Neuroimage Clin 2023; 38:103427. [PMID: 37150021 PMCID: PMC10193020 DOI: 10.1016/j.nicl.2023.103427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/09/2023]
Abstract
Leukodystrophies constitute a large and heterogeneous group of genetic diseases primarily affecting the white matter of the central nervous system. Different disorders target different white matter structural components. Leukodystrophies are most often progressive and fatal. In recent years, novel therapies are emerging and for an increasing number of leukodystrophies trials are being developed. Objective and quantitative metrics are needed to serve as outcome measures in trials. Quantitative MRI yields information on microstructural properties, such as myelin or axonal content and condition, and on the chemical composition of white matter, in a noninvasive fashion. By providing information on white matter microstructural involvement, quantitative MRI may contribute to the evaluation and monitoring of leukodystrophies. Many distinct MR techniques are available at different stages of development. While some are already clinically applicable, others are less far developed and have only or mainly been applied in healthy subjects. In this review, we explore the background, current status, potential and challenges of available quantitative MR techniques in the context of leukodystrophies.
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Affiliation(s)
- Menno D Stellingwerff
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Child Neurology, Emma Children's Hospital, and Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Petra J W Pouwels
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Department of Radiology and Nuclear Medicine, and Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Stefan D Roosendaal
- Amsterdam UMC Location University of Amsterdam, Department of Radiology, Meibergdreef 9, Amsterdam, the Netherlands
| | - Frederik Barkhof
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Department of Radiology and Nuclear Medicine, and Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands; University College London, Institutes of Neurology and Healthcare Engineering, London, UK
| | - Marjo S van der Knaap
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Child Neurology, Emma Children's Hospital, and Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands; Vrije Universiteit Amsterdam, Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, De Boelelaan 1105, Amsterdam, the Netherlands.
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7
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Milotta G, Corbin N, Lambert C, Lutti A, Mohammadi S, Callaghan MF. Mitigating the impact of flip angle and orientation dependence in single compartment R2* estimates via 2-pool modeling. Magn Reson Med 2023; 89:128-143. [PMID: 36161672 PMCID: PMC9827921 DOI: 10.1002/mrm.29428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE The effective transverse relaxation rate (R 2 * $$ {\mathrm{R}}_2^{\ast } $$ ) is influenced by biological features that make it a useful means of probing brain microstructure. However, confounding factors such as dependence on flip angle (α) and fiber orientation with respect to the main field (θ $$ \uptheta $$ ) complicate interpretation. The α- andθ $$ \uptheta $$ -dependence stem from the existence of multiple sub-voxel micro-environments (e.g., myelin and non-myelin water compartments). Ordinarily, it is challenging to quantify these sub-compartments; therefore, neuroscientific studies commonly make the simplifying assumption of a mono-exponential decay obtaining a singleR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimate per voxel. In this work, we investigated how the multi-compartment nature of tissue microstructure affects single compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates. METHODS We used 2-pool (myelin and non-myelin water) simulations to characterize the bias in single compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates. Based on our numeric observations, we introduced a linear model that partitionsR 2 * $$ {\mathrm{R}}_2^{\ast } $$ into α-dependent and α-independent components and validated this in vivo at 7T. We investigated the dependence of both components on the sub-compartment properties and assessed their robustness, orientation dependence, and reproducibility empirically. RESULTS R 2 * $$ {\mathrm{R}}_2^{\ast } $$ increased with myelin water fraction and residency time leading to a linear dependence on α. We observed excellent agreement between our numeric and empirical results. Furthermore, the α-independent component of the proposed linear model was robust to the choice of α and reduced dependence on fiber orientation, although it suffered from marginally higher noise sensitivity. CONCLUSION We have demonstrated and validated a simple approach that mitigates flip angle and orientation biases in single-compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates.
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Affiliation(s)
- Giorgia Milotta
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
| | - Nadège Corbin
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536CNRS/University BordeauxBordeauxFrance
| | - Christian Lambert
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department for Clinical NeuroscienceLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Siawoosh Mohammadi
- Department of Systems NeurosciencesUniversity Medical Center Hamburg‐EppendorfHamburgGermany
- Department of NeurophysicsMax Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
| | - Martina F. Callaghan
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
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Piredda GF, Hilbert T, Ravano V, Canales-Rodríguez EJ, Pizzolato M, Meuli R, Thiran JP, Richiardi J, Kober T. Data-driven myelin water imaging based on T 1 and T 2 relaxometry. NMR IN BIOMEDICINE 2022; 35:e4668. [PMID: 34936147 DOI: 10.1002/nbm.4668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
Long acquisition times preclude the application of multiecho spin echo (MESE) sequences for myelin water fraction (MWF) mapping in daily clinical practice. In search of alternative methods, previous studies of interest explored the biophysical modeling of MWF from measurements of different tissue properties that can be obtained in scan times shorter than those required for the MESE. In this work, a novel data-driven estimation of MWF maps from fast relaxometry measurements is proposed and investigated. T1 and T2 relaxometry maps were acquired in a cohort of 20 healthy subjects along with a conventional MESE sequence. Whole-brain quantitative mapping was achieved with a fast protocol in 6 min 24 s. Reference MWF maps were derived from the MESE sequence (TA = 11 min 17 s) and their data-driven estimation from relaxometry measurements was investigated using three different modeling strategies: two general linear models (GLMs) with linear and quadratic regressors, respectively; a random forest regression model; and two deep neural network architectures, a U-Net and a conditional generative adversarial network (cGAN). Models were validated using a 10-fold crossvalidation. The resulting maps were visually and quantitatively compared by computing the root mean squared error (RMSE) between the estimated and reference MWF maps, the intraclass correlation coefficients (ICCs) between corresponding MWF values in different brain regions, and by performing Bland-Altman analysis. Qualitatively, the estimated maps appear to generally provide a similar, yet more blurred MWF contrast in comparison with the reference, with the cGAN model best capturing MWF variabilities in small structures. By estimating the average adjusted coefficient of determination of the GLM with quadratic regressors, we showed that 87% of the variability in the MWF values can be explained by relaxation times alone. Further quantitative analysis showed an average RMSE smaller than 0.1% for all methods. The ICC was greater than 0.81 for all methods, and the bias smaller than 2.19%. It was concluded that this work confirms the notion that relaxometry parameters contain a large part of the information on myelin water and that MWF maps can be generated from T1 /T2 data with minimal error. Among the investigated modeling approaches, the cGAN provided maps with the best trade-off between accuracy and blurriness. Fast relaxometry, like the 6 min 24 s whole-brain protocol used in this work in conjunction with machine learning, may thus have the potential to replace time-consuming MESE acquisitions.
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Affiliation(s)
- Gian Franco Piredda
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Tom Hilbert
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Veronica Ravano
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | - Marco Pizzolato
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Reto Meuli
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jean-Philippe Thiran
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jonas Richiardi
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Tobias Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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9
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Kiely M, Triebswetter C, Cortina LE, Gong Z, Alsameen MH, Spencer RG, Bouhrara M. Insights into human cerebral white matter maturation and degeneration across the adult lifespan. Neuroimage 2022; 247:118727. [PMID: 34813969 PMCID: PMC8792239 DOI: 10.1016/j.neuroimage.2021.118727] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/15/2021] [Accepted: 11/12/2021] [Indexed: 01/01/2023] Open
Abstract
White matter (WM) microstructural properties change across the adult lifespan and with neuronal diseases. Understanding microstructural changes due to aging is paramount to distinguish them from neuropathological changes. Conducted on a large cohort of 147 cognitively unimpaired subjects, spanning a wide age range of 21 to 94 years, our study evaluated sex- and age-related differences in WM microstructure. Specifically, we used diffusion tensor imaging (DTI) magnetic resonance imaging (MRI) indices, sensitive measures of myelin and axonal density in WM, and myelin water fraction (MWF), a measure of the fraction of the signal of water trapped within the myelin sheets, to probe these differences. Furthermore, we examined regional correlations between MWF and DTI indices to evaluate whether the DTI metrics provide information complementary to MWF. While sexual dimorphism was, overall, nonsignificant, we observed region-dependent differences in MWF, that is, myelin content, and axonal density with age and found that both exhibit nonlinear, but distinct, associations with age. Furthermore, DTI indices were moderately correlated with MWF, indicating their good sensitivity to myelin content as well as to other constituents of WM tissue such as axonal density. The microstructural differences captured by our MRI metrics, along with their weak to moderate associations with MWF, strongly indicate the potential value of combining these outcome measures in a multiparametric approach. Furthermore, our results support the last-in-first-out and the gain-predicts-loss hypotheses of WM maturation and degeneration. Indeed, our results indicate that the posterior WM regions are spared from neurodegeneration as compared to anterior regions, while WM myelination follows a temporally symmetric time course across the adult life span.
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Affiliation(s)
- Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Luis E Cortina
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Maryam H Alsameen
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, USA.
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10
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McDowell AR, Petrova N, Carassiti D, Miquel ME, Thomas DL, Barker GJ, Schmierer K, Wood TC. High-resolution quantitative MRI of multiple sclerosis spinal cord lesions. Magn Reson Med 2022; 87:2914-2921. [PMID: 35014736 PMCID: PMC9208576 DOI: 10.1002/mrm.29152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 11/10/2022]
Abstract
PURPOSE Validation of quantitative MR measures for myelin imaging in the postmortem multiple sclerosis spinal cord. METHODS Four fixed spinal cord samples were imaged first with a 3T clinical MR scanner to identify areas of interest for scanning, and then with a 7T small bore scanner using a multicomponent-driven equilibrium single-pulse observation of T1 and T2 protocol to produce apparent proton density, T1 , T2 , myelin water, intracellular water, and free-water fraction maps. After imaging, the cords were sectioned and stained with histological markers (hematoxylin and eosin, myelin basic protein, and neurofilament protein), which were quantitatively compared with the MR maps. RESULTS Excellent correspondence was found between high-resolution MR parameter maps and histology, particularly for apparent proton density MRI and myelin basic protein staining. CONCLUSION High-resolution quantitative MRI of the spinal cord provides biologically meaningful measures, and could be beneficial to diagnose and track multiple sclerosis lesions in the spinal cord.
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Affiliation(s)
- Amy R McDowell
- Queen Square Centre for Neuromuscular Diseases, UCL, London, United Kingdom
| | - Natalia Petrova
- The Blizard Institute (Neuroscience, Surgery & Trauma), Queen Mary University of London, Barts and The London School of Medicine & Dentistry, London, United Kingdom
| | - Daniele Carassiti
- The Blizard Institute (Neuroscience, Surgery & Trauma), Queen Mary University of London, Barts and The London School of Medicine & Dentistry, London, United Kingdom
| | - Marc E Miquel
- Clinical Physics, Barts Health NHS Trust, London, United Kingdom
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | | | - Klaus Schmierer
- The Blizard Institute (Neuroscience, Surgery & Trauma), Queen Mary University of London, Barts and The London School of Medicine & Dentistry, London, United Kingdom.,Clinical Board Medicine (Neuroscience), Barts Health NHS Trust, The Royal London Hospital, London, United Kingdom
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11
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Omer N, Galun M, Stern N, Blumenfeld-Katzir T, Ben-Eliezer N. Data-driven algorithm for myelin water imaging: Probing subvoxel compartmentation based on identification of spatially global tissue features. Magn Reson Med 2021; 87:2521-2535. [PMID: 34958690 DOI: 10.1002/mrm.29125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 01/10/2023]
Abstract
PURPOSE Multicomponent analysis of MRI T2 relaxation time (mcT2 ) is commonly used for estimating myelin content by separating the signal at each voxel into its underlying distribution of T2 values. This voxel-based approach is challenging due to the large ambiguity in the multi-T2 space and the low SNR of MRI signals. Herein, we present a data-driven mcT2 analysis, which utilizes the statistical strength of identifying spatially global mcT2 motifs in white matter segments before deconvolving the local signal at each voxel. METHODS Deconvolution is done using a tailored optimization scheme, which incorporates the global mcT2 motifs without additional prior assumptions regarding the number of microscopic components. The end results of this process are voxel-wise myelin water fraction maps. RESULTS Validations are shown for computer-generated signals, uniquely designed subvoxel mcT2 phantoms, and in vivo human brain. Results demonstrated excellent fitting accuracy, both for the numerical and the physical mcT2 phantoms, exhibiting excellent agreement between calculated myelin water fraction and ground truth. Proof-of-concept in vivo validation is done by calculating myelin water fraction maps for white matter segments of the human brain. Interscan stability of myelin water fraction values was also estimated, showing good correlation between scans. CONCLUSION We conclude that studying global tissue motifs prior to performing voxel-wise mcT2 analysis stabilizes the optimization scheme and efficiently overcomes the ambiguity in the T2 space. This new approach can improve myelin water imaging and the investigation of microstructural compartmentation in general.
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Affiliation(s)
- Noam Omer
- The Department of Biomedical Engineering, Tel-Aviv University, Tel Aviv, Israel
| | - Meirav Galun
- Department of Computer Science and Applied Mathematics, Weitzman Institute of Science, Rehovot, Israel
| | - Neta Stern
- The Department of Biomedical Engineering, Tel-Aviv University, Tel Aviv, Israel
| | | | - Noam Ben-Eliezer
- The Department of Biomedical Engineering, Tel-Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.,Center for Advanced Imaging Innovation and Research (CAI2R), New York University Langone Medical Center, New York, New York, USA
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12
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Khattar N, Triebswetter C, Kiely M, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Investigation of the association between cerebral iron content and myelin content in normative aging using quantitative magnetic resonance neuroimaging. Neuroimage 2021; 239:118267. [PMID: 34139358 PMCID: PMC8370037 DOI: 10.1016/j.neuroimage.2021.118267] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/24/2022] Open
Abstract
Myelin loss and iron accumulation are cardinal features of aging and various neurodegenerative diseases. Oligodendrocytes incorporate iron as a metabolic substrate for myelin synthesis and maintenance. An emerging hypothesis in Alzheimer’s disease research suggests that myelin breakdown releases substantial stores of iron that may accumulate, leading to further myelin breakdown and neurodegeneration. We assessed associations between iron content and myelin content in critical brain regions using quantitative magnetic resonance imaging (MRI) on a cohort of cognitively unimpaired adults ranging in age from 21 to 94 years. We measured whole-brain myelin water fraction (MWF), a surrogate of myelin content, using multicomponent relaxometry, and whole-brain iron content using susceptibility weighted imaging in all individuals. MWF was negatively associated with iron content in most brain regions evaluated indicating that lower myelin content corresponds to higher iron content. Moreover, iron content was significantly higher with advanced age in most structures, with men exhibiting a trend towards higher iron content as compared to women. Finally, relationship between MWF and age, in all brain regions investigated, suggests that brain myelination continues until middle age, followed by degeneration at older ages. This work establishes a foundation for further investigations of the etiology and sequelae of myelin breakdown and iron accumulation in neurodegeneration and may lead to new imaging markers for disease progression and treatment.
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Affiliation(s)
- Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States.
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13
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Olivieri B, Rampakakis E, Gilbert G, Fezoua A, Wintermark P. Myelination may be impaired in neonates following birth asphyxia. NEUROIMAGE-CLINICAL 2021; 31:102678. [PMID: 34082365 PMCID: PMC8182124 DOI: 10.1016/j.nicl.2021.102678] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/17/2021] [Accepted: 04/12/2021] [Indexed: 01/23/2023]
Abstract
Myelination is a developmental process that intensifies after birth during the first years of life. We used a T2* mapping sequence to assess myelination in healthy and critically ill neonates with neonatal encephalopathy. Birth asphyxia, in addition to causing the previously well-described direct injury to the brain, may impair myelination.
Background Myelination is a developmental process that begins during the end of gestation, intensifies after birth over the first years of life, and continues well into adolescence. Any event leading to brain injury around the time of birth and during the perinatal period, such as birth asphyxia, may impair this critical process. Currently, the impact of such brain injury related to birth asphyxia on the myelination process is unknown. Objective To assess the myelination pattern over the first month of life in neonates with neonatal encephalopathy (NE) developing brain injury, compared to neonates without injury (i.e., healthy neonates and neonates with NE who do not develop brain injury). Methods Brain magnetic resonance imaging (MRI) was performed around day of life 2, 10, and 30 in healthy neonates and near-term/term neonates with NE who were treated with hypothermia. We evaluated myelination in various regions of interest using a T2* mapping sequence. In each region of interest, we compared the T2* values of the neonates with NE with brain injury to the values of the neonates without injury, according to the MRI timing, by using a repeated measures generalized linear mixed model. Results We obtained 74 MRI scans over the first month of life for 6 healthy neonates, 17 neonates with NE who were treated with hypothermia and did not develop brain injury, and 16 neonates with NE who were treated with hypothermia and developed brain injury. The T2* values significantly increased in the neonates with NE who developed injury in the posterior limbs of the internal capsule (day 2: p < 0.001; day 10: p < 0.001; and day 30: p < 0.001), the thalami (day 2: p = 0.001; day 10: p = 0.006; and day 30: p = 0.016), the lentiform nuclei (day 2: p = 0.005), the anterior white matter (day 2: p = 0.002; day 10: p = 0.006; and day 30: p = 0.002), the posterior white matter (day 2: p = 0.001; day 10: p = 0.008; and day 30: p = 0.03), the genu of the corpus callosum (day 2: p = 0.01; and day 10: p = 0.006), and the optic radiations (day 30: p < 0.001). Conclusion In the neonates with NE who were treated with hypothermia and developed brain injury, birth asphyxia impaired myelination in the regions that are myelinated at birth or soon after birth (the posterior limbs of internal capsule, the thalami, and the lentiform nuclei), in the regions where the myelination process begins only after the perinatal period (optic radiations), and in the regions where this process does not occur until months after birth (anterior/posterior white matter), which suggests that birth asphyxia, in addition to causing the previously well-described direct injury to the brain, may impair myelination.
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Affiliation(s)
- Bianca Olivieri
- Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada
| | - Emmanouil Rampakakis
- Medical Affairs, JSS Medical Research, Montreal, Québec, Canada; Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, QC, Canada
| | | | - Aliona Fezoua
- Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada
| | - Pia Wintermark
- Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada; Department of Pediatrics, Division of Newborn Medicine, Montreal Children's Hospital, McGill University, Montreal, QC, Canada.
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14
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Prevost VH, Yung A, Morris SR, Vavasour IM, Samadi-Bahrami Z, Moore GRW, Laule C, Mackay A, Kozlowski P. Temperature dependence and histological correlation of inhomogeneous magnetization transfer and myelin water imaging in ex vivo brain. Neuroimage 2021; 236:118046. [PMID: 33848620 DOI: 10.1016/j.neuroimage.2021.118046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The promise of inhomogeneous magnetization transfer (ihMT) as a new myelin imaging method was studied in ex vivo human brain tissue and in relation to myelin water fraction (MWF). The temperature dependence of both methods was characterized, as well as their correspondence with a histological measure of myelin content. Unfiltered and filtered ihMT protocols were studied by adjusting the saturation scheme to preserve or attenuate signal from tissue with short dipolar relaxation time T1D. METHODS ihMT ratio (ihMTR) and MWF maps were acquired at 7 T from formalin-fixed human brain samples at 22.5 °C, 30 °C and 37 °C. The impact of temperature on unfiltered ihMTR, filtered ihMTR and MWF was investigated and compared to myelin basic protein staining. RESULTS Unfiltered ihMTR exhibited no temperature dependence, whereas filtered ihMTR increased with increasing temperature. MWF decreased at higher temperature, with an increasing prevalence of areas where the myelin water signal was unreliably determined, likely related to a reduction in T2 peak separability at higher temperatures ex vivo. MWF and ihMTR showed similar per-sample correlation with myelin staining at room temperature. At 37 °C, filtered ihMTR was more strongly correlated with myelin staining and had increased dynamic range compared to unfiltered ihMTR. CONCLUSIONS Given the temperature dependence of filtered ihMT, increased dynamic range, and strong myelin specificity that persists at higher temperatures, we recommend carefully controlled temperatures close to 37 °C for filtered ihMT acquisitions. Unfiltered ihMT may also be useful, due to its independence from temperature, higher amplitude values, and sensitivity to short T1D components. Ex vivo myelin water imaging should be performed at room temperature, to avoid fitting issues found at higher temperatures.
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Affiliation(s)
- Valentin H Prevost
- University of British Columbia MRI Research Centre, 2221 Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada.
| | - Andrew Yung
- University of British Columbia MRI Research Centre, 2221 Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada.
| | - Sarah R Morris
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada; Radiology, University of British Columbia, 2775 Laurel Street, 11th Floor, Vancouver, BC V5Z 1M9, Canada; ICORD (International Collaboration on Repair Discoveries), 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
| | - Irene M Vavasour
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada.
| | - Zahra Samadi-Bahrami
- Pathology & Laboratory Medicine, University of British Columbia, G105-2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada.
| | - G R Wayne Moore
- Pathology & Laboratory Medicine, University of British Columbia, G105-2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada.
| | - Cornelia Laule
- Radiology, University of British Columbia, 2775 Laurel Street, 11th Floor, Vancouver, BC V5Z 1M9, Canada; Pathology & Laboratory Medicine, University of British Columbia, G105-2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada; Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada; ICORD (International Collaboration on Repair Discoveries), 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
| | - Alex Mackay
- University of British Columbia MRI Research Centre, 2221 Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada; Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada; Radiology, University of British Columbia, 2775 Laurel Street, 11th Floor, Vancouver, BC V5Z 1M9, Canada.
| | - Piotr Kozlowski
- University of British Columbia MRI Research Centre, 2221 Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada; Radiology, University of British Columbia, 2775 Laurel Street, 11th Floor, Vancouver, BC V5Z 1M9, Canada; ICORD (International Collaboration on Repair Discoveries), 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
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15
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Bangen KJ, Delano-Wood L, Deoni SCL, Clark AL, Evangelista ND, Hoffman SN, Sorg SF, Holmqvist S, Osuna J, Weigand AJ, Jak AJ, Bondi MW, Lamar M. Decreased myelin content of the fornix predicts poorer memory performance beyond vascular risk, hippocampal volume, and fractional anisotropy in nondemented older adults. Brain Imaging Behav 2021; 15:2563-2571. [PMID: 33638111 PMCID: PMC8500888 DOI: 10.1007/s11682-021-00458-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/18/2022]
Abstract
Alterations to cerebral white matter tracts have been associated with cognitive decline in aging and Alzheimer's disease (AD). In particular, the fornix has been implicated as especially vulnerable given that it represents the primary outflow tract of the hippocampus. Despite this, little work has focused on the fornix using a potential early marker of white matter degeneration-myelin water fraction (MWF; an in vivo marker of myelin content). Therefore, we sought to (1) clarify associations between MWF in the fornix and memory functioning, and (2) examine whether fornix MWF relates to memory performance above and beyond hippocampal volume and conventional imaging measures of white matter that may not be as specific to alterations in myelin content. Forty nondemented older adults (mean age = 72.9 years) underwent an MRI exam and neuropsychological assessment. Multicomponent driven equilibrium single pulse observation of T1 and T2 (mcDESPOT) was used to quantify fornix MWF and diffusion tensor imaging (DTI) was used to measure fornix fractional anisotropy (FA). Adjusting for age, sex, education, and vascular risk factors, linear regression models revealed that, lower fornix MWF was significantly associated with poorer memory functioning (β = 0.405, p = .007) across our sample of older adults. Notably, fornix MWF remained a significant predictor of memory functioning (β = 0.380, p = .015) even after adjusting for fornix DTI FA and hippocampal volume (in addition to the above covariates). Given the observed associations between myelin and memory in older adults without dementia, MWF may be a useful early marker of dementia risk.
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Affiliation(s)
- Katherine J Bangen
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA. .,Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA.
| | - Lisa Delano-Wood
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA.,Psychology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Sean C L Deoni
- Department of Pediatrics, Brown University, Providence, RI, USA
| | - Alexandra L Clark
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA.,Psychology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Nicole D Evangelista
- Center for Cognitive Aging and Memory, Department of Clinical and Health Psychology, McKnight Brain Institute, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Samantha N Hoffman
- San Diego Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California, San Diego, CA, USA
| | - Scott F Sorg
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA.,Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA
| | - Sophia Holmqvist
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Jessica Osuna
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA.,Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA
| | - Alexandra J Weigand
- Center for Cognitive Aging and Memory, Department of Clinical and Health Psychology, McKnight Brain Institute, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Amy J Jak
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA.,Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA.,Psychology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Mark W Bondi
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, Mail Code 151B, La Jolla, CA, 92093-9151, USA.,Psychology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Melissa Lamar
- Rush Alzheimer's Disease Center, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA
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16
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Mohammadi S, Callaghan MF. Towards in vivo g-ratio mapping using MRI: Unifying myelin and diffusion imaging. J Neurosci Methods 2021; 348:108990. [PMID: 33129894 PMCID: PMC7840525 DOI: 10.1016/j.jneumeth.2020.108990] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/21/2020] [Accepted: 10/20/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND The g-ratio, quantifying the comparative thickness of the myelin sheath encasing an axon, is a geometrical invariant that has high functional relevance because of its importance in determining neuronal conduction velocity. Advances in MRI data acquisition and signal modelling have put in vivo mapping of the g-ratio, across the entire white matter, within our reach. This capacity would greatly increase our knowledge of the nervous system: how it functions, and how it is impacted by disease. NEW METHOD This is the second review on the topic of g-ratio mapping using MRI. RESULTS This review summarizes the most recent developments in the field, while also providing methodological background pertinent to aggregate g-ratio weighted mapping, and discussing pitfalls associated with these approaches. COMPARISON WITH EXISTING METHODS Using simulations based on recently published data, this review reveals caveats to the state-of-the-art calibration methods that have been used for in vivo g-ratio mapping. It highlights the need to estimate both the slope and offset of the relationship between these MRI-based markers and the true myelin volume fraction if we are really to achieve the goal of precise, high sensitivity g-ratio mapping in vivo. Other challenges discussed in this review further evidence the need for gold standard measurements of human brain tissue from ex vivo histology. CONCLUSIONS We conclude that the quest to find the most appropriate MRI biomarkers to enable in vivo g-ratio mapping is ongoing, with the full potential of many novel techniques yet to be investigated.
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Affiliation(s)
- Siawoosh Mohammadi
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Martina F Callaghan
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, UK
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17
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Dvorak AV, Ljungberg E, Vavasour IM, Lee LE, Abel S, Li DKB, Traboulsee A, MacKay AL, Kolind SH. Comparison of multi echo T 2 relaxation and steady state approaches for myelin imaging in the central nervous system. Sci Rep 2021; 11:1369. [PMID: 33446710 PMCID: PMC7809349 DOI: 10.1038/s41598-020-80585-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
The traditional approach for measuring myelin-associated water with quantitative magnetic resonance imaging (MRI) uses multi-echo T2 relaxation data to calculate the myelin water fraction (MWF). A fundamentally different approach, abbreviated “mcDESPOT”, uses a more efficient steady-state acquisition to generate an equivalent metric (fM). Although previous studies have demonstrated inherent instability and bias in the complex mcDESPOT analysis procedure, fM has often been used as a surrogate for MWF. We produced and compared multivariate atlases of MWF and fM in healthy human brain and cervical spinal cord (available online) and compared their ability to detect multiple sclerosis pathology. A significant bias was found in all regions (p < 10–5), albeit reversed for spinal cord (fM-MWF = − 3.4%) compared to brain (+ 6.2%). MWF and fM followed an approximately linear relationship for regions with MWF < ~ 10%. For MWF > ~ 10%, the relationship broke down and fM no longer increased in tandem with MWF. For multiple sclerosis patients, MWF and fM Z score maps showed overlapping areas of low Z score and similar trends between patients and brain regions, although those of fM generally had greater spatial extent and magnitude of severity. These results will guide future choice of myelin-sensitive quantitative MRI and improve interpretation of studies using either myelin imaging approach.
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Affiliation(s)
- Adam V Dvorak
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada. .,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.
| | - Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Irene M Vavasour
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Lisa Eunyoung Lee
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Shawna Abel
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - David K B Li
- Radiology, University of British Columbia, Vancouver, BC, Canada.,Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Anthony Traboulsee
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Alex L MacKay
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Shannon H Kolind
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada.,Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
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18
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Dvorak AV, Swift-LaPointe T, Vavasour IM, Lee LE, Abel S, Russell-Schulz B, Graf C, Wurl A, Liu H, Laule C, Li DKB, Traboulsee A, Tam R, Boyd LA, MacKay AL, Kolind SH. An atlas for human brain myelin content throughout the adult life span. Sci Rep 2021; 11:269. [PMID: 33431990 PMCID: PMC7801525 DOI: 10.1038/s41598-020-79540-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Myelin water imaging is a quantitative neuroimaging technique that provides the myelin water fraction (MWF), a metric highly specific to myelin content, and the intra-/extra-cellular T2 (IET2), which is related to water and iron content. We coupled high-resolution data from 100 adults with gold-standard methodology to create an optimized anatomical brain template and accompanying MWF and IET2 atlases. We then used the MWF atlas to characterize how myelin content relates to demographic factors. In most brain regions, myelin content followed a quadratic pattern of increase during the third decade of life, plateau at a maximum around the fifth decade, then decrease during later decades. The ranking of mean myelin content between brain regions remained consistent across age groups. These openly available normative atlases can facilitate evaluation of myelin imaging results on an individual basis and elucidate the distribution of myelin content between brain regions and in the context of aging.
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Affiliation(s)
- Adam V Dvorak
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada. .,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.
| | | | - Irene M Vavasour
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Lisa Eunyoung Lee
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Shawna Abel
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | | | - Carina Graf
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Anika Wurl
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Hanwen Liu
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Cornelia Laule
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada.,Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - David K B Li
- Radiology, University of British Columbia, Vancouver, BC, Canada.,Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Anthony Traboulsee
- Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Roger Tam
- Radiology, University of British Columbia, Vancouver, BC, Canada.,Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Lara A Boyd
- Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada
| | - Alex L MacKay
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Shannon H Kolind
- Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada.,Radiology, University of British Columbia, Vancouver, BC, Canada.,Medicine (Neurology), University of British Columbia, Vancouver, BC, Canada
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19
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Qian W, Khattar N, Cortina LE, Spencer RG, Bouhrara M. Nonlinear associations of neurite density and myelin content with age revealed using multicomponent diffusion and relaxometry magnetic resonance imaging. Neuroimage 2020; 223:117369. [PMID: 32931942 PMCID: PMC7775614 DOI: 10.1016/j.neuroimage.2020.117369] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022] Open
Abstract
Most magnetic resonance imaging (MRI) studies investigating the relationship between regional brain myelination or axonal density and aging have relied upon nonspecific methods to probe myelin and axonal content, including diffusion tensor imaging and relaxation time mapping. While these studies have provided pivotal insights into changes in cerebral architecture with aging and pathology, details of the underlying microstructural alterations have not been fully elucidated. In the current study, we used the BMC-mcDESPOT analysis, a direct and specific multicomponent relaxometry method for imaging of myelin water fraction (MWF), a marker of myelin content, and NODDI, an emerging multicomponent diffusion technique, for neurite density index (NDI) imaging, a proxy of axonal density. We investigated age-related differences in MWF and NDI in several white matter brain regions in a cohort of cognitively unimpaired participants over a wide age range. Our results indicate a quadratic, inverted U-shape, relationship between MWF and age in all brain regions investigated, suggesting that myelination continues until middle age followed by a decrease at older ages, in agreement with previous work. We found a similarly complex regional association between NDI and age, with several cerebral structures also exhibiting a quadratic, inverted U-shape, relationship. This novel observation suggests an increase in axonal density until the fourth decade of age followed by a rapid loss at older ages. We also observed that these age-related differences in MWF and NDI vary across different brain regions, as expected. Finally, our study indicates no significant association between MWF and NDI in most cerebral structures investigated, although this association approached significance in a limited number of brain regions, indicating the complementary nature of their information and encouraging further investigation. Overall, we find evidence of nonlinear associations between age and myelin or axonal density in a sample of well-characterized adults, using direct myelin and axonal content imaging methods.
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Affiliation(s)
- Wenshu Qian
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Nikkita Khattar
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Luis E Cortina
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Richard G Spencer
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Mustapha Bouhrara
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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20
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Wiggermann V, Vavasour IM, Kolind SH, MacKay AL, Helms G, Rauscher A. Non-negative least squares computation for in vivo myelin mapping using simulated multi-echo spin-echo T 2 decay data. NMR IN BIOMEDICINE 2020; 33:e4277. [PMID: 32124505 DOI: 10.1002/nbm.4277] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/20/2020] [Accepted: 01/26/2020] [Indexed: 06/10/2023]
Abstract
Multi-compartment T2 mapping has gained particular relevance for the study of myelin water in the brain. As a facilitator of rapid saltatory axonal signal transmission, myelin is a cornerstone indicator of white matter development and function. Regularized non-negative least squares fitting of multi-echo T2 data has been widely employed for the computation of the myelin water fraction (MWF), and the obtained MWF maps have been histopathologically validated. MWF measurements depend upon the quality of the data acquisition, B1+ homogeneity and a range of fitting parameters. In this special issue article, we discuss the relevance of these factors for the accurate computation of multi-compartment T2 and MWF maps. We generated multi-echo spin-echo T2 decay curves following the Carr-Purcell-Meiboom-Gill approach for various myelin concentrations and myelin T2 scenarios by simulating the evolution of the magnetization vector between echoes based on the Bloch equations. We demonstrated that noise and imperfect refocusing flip angles yield systematic underestimations in MWF and intra-/extracellular water geometric mean T2 (gmT2 ). MWF estimates were more stable than myelin water gmT2 time across different settings of the T2 analysis. We observed that the lower limit of the T2 distribution grid should be slightly shorter than TE1 . Both TE1 and the acquisition echo spacing also have to be sufficiently short to capture the rapidly decaying myelin water T2 signal. Among all parameters of interest, the estimated MWF and intra-/extracellular water gmT2 differed by approximately 0.13-4 percentage points and 3-4 ms, respectively, from the true values, with larger deviations observed in the presence of greater B1+ inhomogeneities and at lower signal-to-noise ratio. Tailoring acquisition strategies may allow us to better characterize the T2 distribution, including the myelin water, in vivo.
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Affiliation(s)
- V Wiggermann
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
| | - I M Vavasour
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - S H Kolind
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
- Department of Medicine (Division Neurology), University of British Columbia, Vancouver, Canada
| | - A L MacKay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
| | - G Helms
- Department of Clinical Sciences Lund (IKVL), Medical Radiation Physics, Lund University, Lund, Sweden
| | - A Rauscher
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada
- Department of Radiology, University of British Columbia, Vancouver, Canada
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21
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van der Weijden CWJ, García DV, Borra RJH, Thurner P, Meilof JF, van Laar PJ, Dierckx RAJO, Gutmann IW, de Vries EFJ. Myelin quantification with MRI: A systematic review of accuracy and reproducibility. Neuroimage 2020; 226:117561. [PMID: 33189927 DOI: 10.1016/j.neuroimage.2020.117561] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/27/2020] [Accepted: 11/07/2020] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Currently, multiple sclerosis is treated with anti-inflammatory therapies, but these treatments lack efficacy in progressive disease. New treatment strategies aim to repair myelin damage and efficacy evaluation of such new therapies would benefit from validated myelin imaging techniques. Several MRI methods for quantification of myelin density are available now. This systematic review aims to analyse the performance of these MRI methods. METHODS Studies comparing myelin quantification by MRI with histology, the current gold standard, or assessing reproducibility were retrieved from PubMed/MEDLINE and Embase (until December 2019). Included studies assessed both myelin histology and MRI quantitatively. Correlation or variance measurements were extracted from the studies. Non-parametric tests were used to analyse differences in study methodologies. RESULTS The search yielded 1348 unique articles. Twenty-two animal studies and 13 human studies correlated myelin MRI with histology. Eighteen clinical studies analysed the reproducibility. Overall bias risk was low or unclear. All MRI methods performed comparably, with a mean correlation between MRI and histology of R2=0.54 (SD=0.30) for animal studies, and R2=0.54 (SD=0.18) for human studies. Reproducibility for the MRI methods was good (ICC=0.75-0.93, R2=0.90-0.98, COV=1.3-27%), except for MTR (ICC=0.05-0.51). CONCLUSIONS Overall, MRI-based myelin imaging methods show a fairly good correlation with histology and a good reproducibility. However, the amount of validation data is too limited and the variability in performance between studies is too large to select the optimal MRI method for myelin quantification yet.
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Affiliation(s)
- Chris W J van der Weijden
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - David Vállez García
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ronald J H Borra
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Patrick Thurner
- Universitätsklinik für Radiologie und Nuklearmedizin, Medizinische Universität Wien, Währinger Gürtel 18-20, 1090 Wien, Austria.
| | - Jan F Meilof
- Multiple Sclerosis Center Noord Nederland, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Peter-Jan van Laar
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, Zorggroep Twente, Zilvermeeuw 1, 7609 PP Almelo, the Netherlands.
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ingomar W Gutmann
- Physics of Functional Material, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
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22
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Chan KS, Marques JP. Multi-compartment relaxometry and diffusion informed myelin water imaging – Promises and challenges of new gradient echo myelin water imaging methods. Neuroimage 2020; 221:117159. [DOI: 10.1016/j.neuroimage.2020.117159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/08/2023] Open
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23
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Whitaker ST, Nataraj G, Nielsen JF, Fessler JA. Myelin water fraction estimation using small-tip fast recovery MRI. Magn Reson Med 2020; 84:1977-1990. [PMID: 32281179 PMCID: PMC7478173 DOI: 10.1002/mrm.28259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/05/2020] [Accepted: 02/26/2020] [Indexed: 11/09/2022]
Abstract
PURPOSE To demonstrate the feasibility of an optimized set of small-tip fast recovery (STFR) MRI scans for rapidly estimating myelin water fraction (MWF) in the brain. METHODS We optimized a set of STFR scans to minimize the Cramér-Rao Lower Bound of MWF estimates. We evaluated the RMSE of MWF estimates from the optimized scans in simulation. We compared STFR-based MWF estimates (both modeling exchange and not modeling exchange) to multi-echo spin echo (MESE)-based estimates. We used the optimized scans to acquire in vivo data from which a MWF map was estimated. We computed the STFR-based MWF estimates using PERK, a recently developed kernel regression technique, and the MESE-based MWF estimates using both regularized non-negative least squares (NNLS) and PERK. RESULTS In simulation, the optimized STFR scans led to estimates of MWF with low RMSE across a range of tissue parameters and across white matter and gray matter. The STFR-based MWF estimates that modeled exchange compared well to MESE-based MWF estimates in simulation. When the optimized scans were tested in vivo, the MWF map that was estimated using a 3-compartment model with exchange was closer to the MESE-based MWF map. CONCLUSIONS The optimized STFR scans appear to be well suited for estimating MWF in simulation and in vivo when we model exchange in training. In this case, the STFR-based MWF estimates are close to the MESE-based estimates.
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Affiliation(s)
- Steven T. Whitaker
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, USA
| | - Gopal Nataraj
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jeffrey A. Fessler
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, USA
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24
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Lynn JD, Anand C, Arshad M, Homayouni R, Rosenberg DR, Ofen N, Raz N, Stanley JA. Microstructure of Human Corpus Callosum across the Lifespan: Regional Variations in Axon Caliber, Density, and Myelin Content. Cereb Cortex 2020; 31:1032-1045. [PMID: 32995843 DOI: 10.1093/cercor/bhaa272] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/21/2020] [Accepted: 08/21/2020] [Indexed: 12/13/2022] Open
Abstract
The myeloarchitecture of the corpus callosum (CC) is characterized as a mosaic of distinct differences in fiber density of small- and large-diameter axons along the anterior-posterior axis; however, regional and age differences across the lifespan are not fully understood. Using multiecho T2 magnetic resonance imaging combined with multi-T2 fitting, the myelin water fraction (MWF) and geometric-mean of the intra-/extracellular water T2 (geomT2IEW) in 395 individuals (7-85 years; 41% males) were examined. The approach was validated where regional patterns along the CC closely resembled the histology; MWF matched mean axon diameter and geomT2IEW mirrored the density of large-caliber axons. Across the lifespan, MWF exhibited a quadratic association with age in all 10 CC regions with evidence of a positive linear MWF-age relationship among younger participants and minimal age differences in the remainder of the lifespan. Regarding geomT2IEW, a significant linear age × region interaction reflected positive linear age dependence mostly prominent in the regions with the highest density of small-caliber fibers-genu and splenium. In all, these two indicators characterize distinct attributes that are consistent with histology, which is a first. In addition, these results conform to rapid developmental progression of CC myelination leveling in middle age as well as age-related degradation of axon sheaths in older adults.
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Affiliation(s)
- Jonathan D Lynn
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit MI 48201, USA
- Institute of Gerontology, Wayne State University, Detroit MI 48202, USA
| | - Chaitali Anand
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit MI 48201, USA
- Institute of Gerontology, Wayne State University, Detroit MI 48202, USA
| | - Muzamil Arshad
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit MI 48201, USA
| | - Roya Homayouni
- Institute of Gerontology, Wayne State University, Detroit MI 48202, USA
- Department of Psychology, Wayne State University, Detroit MI 48201, USA
| | - David R Rosenberg
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit MI 48201, USA
| | - Noa Ofen
- Institute of Gerontology, Wayne State University, Detroit MI 48202, USA
- Department of Psychology, Wayne State University, Detroit MI 48201, USA
- Lifespan Cognitive Neuroscience, Merrill Palmer Skillman Institute, Wayne State University, Detroit MI 14195, USA
| | - Naftali Raz
- Institute of Gerontology, Wayne State University, Detroit MI 48202, USA
- Department of Psychology, Wayne State University, Detroit MI 48201, USA
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin 14195, Germany
| | - Jeffrey A Stanley
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit MI 48201, USA
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25
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Piredda GF, Hilbert T, Thiran JP, Kober T. Probing myelin content of the human brain with MRI: A review. Magn Reson Med 2020; 85:627-652. [PMID: 32936494 DOI: 10.1002/mrm.28509] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022]
Abstract
Rapid and efficient transmission of electric signals among neurons of vertebrates is ensured by myelin-insulating sheaths surrounding axons. Human cognition, sensation, and motor functions rely on the integrity of these layers, and demyelinating diseases often entail serious cognitive and physical impairments. Magnetic resonance imaging radically transformed the way these disorders are monitored, offering an irreplaceable tool to noninvasively examine the brain structure. Several advanced techniques based on MRI have been developed to provide myelin-specific contrasts and a quantitative estimation of myelin density in vivo. Here, the vast offer of acquisition strategies developed to date for this task is reviewed. Advantages and pitfalls of the different approaches are compared and discussed.
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Affiliation(s)
- Gian Franco Piredda
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tom Hilbert
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jean-Philippe Thiran
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tobias Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland.,Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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26
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Patel Y, Shin J, Drakesmith M, Evans J, Pausova Z, Paus T. Virtual histology of multi-modal magnetic resonance imaging of cerebral cortex in young men. Neuroimage 2020; 218:116968. [DOI: 10.1016/j.neuroimage.2020.116968] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 05/02/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
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27
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Remer J, Dean DC, Chen K, Reiman RA, Huentelman MJ, Reiman EM, Deoni SCL. Longitudinal white matter and cognitive development in pediatric carriers of the apolipoprotein ε4 allele. Neuroimage 2020; 222:117243. [PMID: 32822813 PMCID: PMC7779366 DOI: 10.1016/j.neuroimage.2020.117243] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/01/2020] [Accepted: 08/05/2020] [Indexed: 01/14/2023] Open
Abstract
We have previously demonstrated cross-sectional differences in magnetic resonance imaging (MRI) measurements of white matter myelin and gray matter in infants with or without the apolipoprotein ε4 allele, a major genetic risk factor for late-onset Alzheimer's disease (AD). In this study, we sought to compare longitudinal MRI white matter myelin and cognitive-behavioral changes in infants and young children with and without this allele. Serial MRI and cognitive tests were obtained on 223 infants and young children, including 74 ε4 carriers and 149 non-carriers, 2–68 months of age, matched for age, gestational duration, birth weight, sex ratio, maternal age, education, and socioeconomic status. Automated brain mapping algorithms and non-linear mixed models were used to characterize and compare trajectories of white matter myelin and cognitive-behavioral test scores. The APOE ε4 carriers had statistically significant differences in white matter myelin development, in the uncinate fasciculus, temporal lobe, internal capsule and occipital lobe. Additionally, ε4 carriers had a slightly greater rate of development in early learning composite a surrogate measure of IQ representative of expressive language, receptive language, fine motor, and visual skills, but displayed slightly lower non verbal development quotient scores a composite measure of fine motor and visual skills across the entire age range. This study supports the possibility that ε4 carriers have slightly altered rates of white matter and cognitive development in childhood. It continues to raise questions about the role of APOE in human brain development and the relevance of these developmental differences to the predisposition to AD.
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Affiliation(s)
- Justin Remer
- Advanced Baby Imaging Lab, Rhode Island Hospital, Providence, RI, USA; Department of Pediatrics, Warren Alpert Medical School at Brown University, Providence RI, USA.
| | - Douglas C Dean
- Department of Pediatrics, University of Wisconsin-Madison, Madison WI 53705 USA; Department of Medical Physics, University of Wisconsin-Madison, Madison WI 5305 USA; Waisman Center, University of Wisconsin-Madison, Madison WI 53705 USA
| | - Kewei Chen
- Arizona Alzheimer's Consortium, University of Arizona School of Medicine, Tucson and Phoenix AZ, USA; Banner Alzheimer's Institute, Phoenix, AZ, USA; University of Arizona College of Medicine, Phoenix, AZ, USA; Arizona State University, Phoenix, AZ, USA
| | - Rebecca A Reiman
- Banner Alzheimer's Institute, Phoenix, AZ, USA; Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, USA
| | - Matthew J Huentelman
- Banner Alzheimer's Institute, Phoenix, AZ, USA; Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, USA
| | - Eric M Reiman
- Arizona Alzheimer's Consortium, University of Arizona School of Medicine, Tucson and Phoenix AZ, USA; Banner Alzheimer's Institute, Phoenix, AZ, USA; University of Arizona College of Medicine, Phoenix, AZ, USA; Arizona State University, Phoenix, AZ, USA; Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, USA
| | - Sean C L Deoni
- Advanced Baby Imaging Lab, Rhode Island Hospital, Providence, RI, USA; Department of Pediatrics, Warren Alpert Medical School at Brown University, Providence RI, USA; Maternal, Newborn, and Child Health Discovery and Tools, Bill and Melinda Gates Foundation; Seattle WA, USA
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28
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Piredda GF, Hilbert T, Canales-Rodríguez EJ, Pizzolato M, von Deuster C, Meuli R, Pfeuffer J, Daducci A, Thiran JP, Kober T. Fast and high-resolution myelin water imaging: Accelerating multi-echo GRASE with CAIPIRINHA. Magn Reson Med 2020; 85:209-222. [PMID: 32720406 DOI: 10.1002/mrm.28427] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Although several MRI methods have been explored to achieve in vivo myelin quantification, imaging the whole brain in clinically acceptable times and sufficiently high resolution remains challenging. To address this problem, this work investigates the acceleration of multi-echo T2 acquisitions based on the multi-echo gradient and spin echo (GRASE) sequence using CAIPIRINHA undersampling and adapted k-space reordering patterns. METHODS A prototype multi-echo GRASE sequence supporting CAIPIRINHA parallel imaging was implemented. Multi-echo T2 data were acquired from 12 volunteers using the implemented sequence (1.6 × 1.6 × 1.6 mm3 , 84 slices, acquisition time [TA] = 10:30 min) and a multi-echo spin echo (MESE) sequence as reference (1.6 × 1.6 × 3.2 mm3 , single-slice, TA = 5:41 min). Myelin water fraction (MWF) maps derived from both acquisitions were compared via correlation and Bland-Altman analyses. In addition, scan-rescan datasets were acquired to evaluate the repeatability of the derived maps. RESULTS Resulting maps from the MESE and multi-echo GRASE sequences were found to be correlated (r = 0.83). The Bland-Altman analysis revealed a mean bias of -0.2% (P = .24) with the limits of agreement ranging from -3.7% to 3.3%. The Pearson's correlation coefficient among MWF values obtained from the scan-rescan datasets was found to be 0.95 and the mean bias equal to 0.11% (P = .32), indicating good repeatability of the retrieved maps. CONCLUSION By combining a 3D multi-echo GRASE sequence with CAIPIRINHA sampling, whole-brain MWF maps were obtained in 10:30 min with 1.6 mm isotropic resolution. The good correlation with conventional MESE-based maps demonstrates that the implemented sequence may be a promising alternative to time-consuming MESE acquisitions.
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Affiliation(s)
- Gian Franco Piredda
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Tom Hilbert
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Erick Jorge Canales-Rodríguez
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- FIDMAG Germanes Hospitalàries, Sant Boi de Llobregat, Barcelona, Spain
| | - Marco Pizzolato
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Constantin von Deuster
- Siemens Healthcare AG, Zurich, Switzerland
- SCMI, Swiss Center for Musculoskeletal Imaging, Zurich, Switzerland
| | - Reto Meuli
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Josef Pfeuffer
- Application Development, Siemens Healthcare GmbH, Erlangen, Germany
| | | | - Jean-Philippe Thiran
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Tobias Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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29
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Thapaliya K, Vegh V, Bollmann S, Barth M. Influence of 7T GRE-MRI Signal Compartment Model Choice on Tissue Parameters. Front Neurosci 2020; 14:271. [PMID: 32457565 PMCID: PMC7206227 DOI: 10.3389/fnins.2020.00271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Quantitative assessment of tissue microstructure is important in studying human brain diseases and disorders. Ultra-high field magnetic resonance imaging (MRI) data obtained using a multi-echo gradient echo sequence have been shown to contain information on myelin, axonal, and extracellular compartments in tissue. Quantitative assessment of water fraction, relaxation time (T2*), and frequency shift using multi-compartment models has been shown to be useful in studying white matter properties via specific tissue parameters. It remains unclear how tissue parameters vary with model selection based on 7T multiple echo time gradient-recalled echo (GRE) MRI data. We applied existing signal compartment models to the corpus callosum and investigated whether a three-compartment model can be reduced to two compartments and still resolve white matter parameters [i.e., myelin water fraction (MWF) and g-ratio]. We show that MWF should be computed using a three-compartment model in the corpus callosum, and the g-ratios obtained using three compartment models are consistent with previous reports. We provide results for other parameters, such as signal compartment frequency shifts.
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Affiliation(s)
- Kiran Thapaliya
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
| | - Viktor Vegh
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia.,ARC Centre for Innovation in Biomedical Imaging Technology, Brisbane, QLD, Australia
| | - Steffen Bollmann
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia.,ARC Centre for Innovation in Biomedical Imaging Technology, Brisbane, QLD, Australia
| | - Markus Barth
- Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia.,ARC Centre for Innovation in Biomedical Imaging Technology, Brisbane, QLD, Australia.,School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, Australia
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30
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Jak AJ, Jurick S, Hoffman S, Evangelista ND, Deford N, Keller A, Merritt VC, Sanderson-Cimino M, Sorg S, Delano-Wood L, Bangen KJ. PTSD, but not history of mTBI, is associated with altered myelin in combat-exposed Iraq and Afghanistan Veterans. Clin Neuropsychol 2020; 34:1070-1087. [PMID: 32176590 DOI: 10.1080/13854046.2020.1730975] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To investigate the biological, cognitive, and psychological presentations of combat-exposed Veterans with a history of mild traumatic brain injury (mTBI) and/or posttraumatic stress disorder (PTSD) using a novel white matter imaging technique and comprehensive neuropsychological assessment. METHOD 74 Iraq and Afghanistan Veterans (mean age 33.89, 90.5% male) with history of mTBI (average 7.25 years since injury), PTSD, both, or neither underwent magnetic resonance imaging (MRI) exams including acquisition of a novel imaging technique, multicomponent-driven equilibrium single-pulse observation of T1/T2 (mcDESPOT) to quantify myelin water fraction (MWF), a surrogate measure of myelin content. Participants also underwent comprehensive neuropsychological assessment and three cognitive composite scores (memory, working memory/processing speed, and executive functioning) were created. RESULTS There were no significant group differences on the neuropsychological composite scores. ANCOVAs revealed a main effect of PTSD across all a priori regions of interest (ROI) in which PTSD was associated with higher MWF. There was no main effect of mTBI history or TBI by PTSD interaction on any ROI. Significant positive associations were observed between myelin and PTSD symptoms, but no significant associations were found between myelin and neurobehavioral symptoms. No significant associations were found between myelin in the a priori ROIs and the cognitive composite scores. CONCLUSION This study did not find neuropsychological or MWF differences in combat Veterans with a remote history of mTBI but did find myelin alterations related to PTSD. Psychological trauma should be a primary target for intervention in Veterans with comorbid PTSD and mTBI reporting subjective complaints, given its salience.
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Affiliation(s)
- Amy J Jak
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,VASDHS Center of Excellence for Stress and Mental Health (CESAMH), San Diego, CA, USA.,Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
| | - Sarah Jurick
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,VASDHS Center of Excellence for Stress and Mental Health (CESAMH), San Diego, CA, USA
| | - Samantha Hoffman
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
| | - Nicole D Evangelista
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | | | - Amber Keller
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA
| | - Victoria C Merritt
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA
| | - Mark Sanderson-Cimino
- Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
| | - Scott Sorg
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
| | - Lisa Delano-Wood
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,VASDHS Center of Excellence for Stress and Mental Health (CESAMH), San Diego, CA, USA.,Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
| | - Katherine J Bangen
- Veterans Affairs San Diego Healthcare System (VASDHS), San Diego, CA, USA.,Department of Psychiatry, San Diego School of Medicine, University California, San Diego, CA, USA
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31
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Morris SR, Holmes RD, Dvorak AV, Liu H, Yoo Y, Vavasour IM, Mazabel S, Mädler B, Kolind SH, Li DKB, Siegel L, Beaulieu C, MacKay AL, Laule C. Brain Myelin Water Fraction and Diffusion Tensor Imaging Atlases for 9-10 Year-Old Children. J Neuroimaging 2020; 30:150-160. [PMID: 32064721 DOI: 10.1111/jon.12689] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/18/2019] [Accepted: 01/17/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Myelin water imaging (MWI) and diffusion tensor imaging (DTI) provide information about myelin and axon-related brain microstructure, which can be useful for investigating normal brain development and many childhood brain disorders. While pediatric DTI atlases exist, there are no pediatric MWI atlases available for the 9-10 years old age group. As myelination and structural development occurs throughout childhood and adolescence, studies of pediatric brain pathologies must use age-specific MWI and DTI healthy control data. We created atlases of myelin water fraction (MWF) and DTI metrics for healthy children aged 9-10 years for use as normative data in pediatric neuroimaging studies. METHODS 3D-T1 , DTI, and MWI scans were acquired from 20 healthy children (mean age: 9.6 years, range: 9.2-10.3 years, 4 females). ANTs and FSL registration were used to create quantitative MWF and DTI atlases. Region of interest (ROI) analysis in nine white matter regions was used to compare pediatric MWF with adult MWF values from a recent study and to investigate the correlation between pediatric MWF and DTI metrics. RESULTS Adults had significantly higher MWF than the pediatric cohort in seven of the nine white matter ROIs, but not in the genu of the corpus callosum or the cingulum. In the pediatric data, MWF correlated significantly with mean diffusivity, but not with axial diffusivity, radial diffusivity, or fractional anisotropy. CONCLUSIONS Normative MWF and DTI metrics from a group of 9-10 year old healthy children provide a resource for comparison to pathologies. The age-specific atlases are ready for use in pediatric neuroimaging research and can be accessed: https://sourceforge.net/projects/pediatric-mri-myelin-diffusion/.
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Affiliation(s)
- Sarah R Morris
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | | | - Adam V Dvorak
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada
| | - Hanwen Liu
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada
| | - Youngjin Yoo
- Medical Imaging Technologies, Siemens Healthineers, Princeton, NJ
| | - Irene M Vavasour
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Silvia Mazabel
- Educational and Counseling Psychology, and Special Education, University of British Columbia, Vancouver, BC, Canada
| | | | - Shannon H Kolind
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada.,Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - David K B Li
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada.,Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Linda Siegel
- Educational and Counseling Psychology, and Special Education, University of British Columbia, Vancouver, BC, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Alex L MacKay
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Cornelia Laule
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada.,Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
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32
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Lee J, Hyun JW, Lee J, Choi EJ, Shin HG, Min K, Nam Y, Kim HJ, Oh SH. So You Want to Image Myelin Using MRI: An Overview and Practical Guide for Myelin Water Imaging. J Magn Reson Imaging 2020; 53:360-373. [PMID: 32009271 DOI: 10.1002/jmri.27059] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/22/2022] Open
Abstract
Myelin water imaging (MWI) is an MRI imaging biomarker for myelin. This method can generate an in vivo whole-brain myelin water fraction map in approximately 10 minutes. It has been applied in various applications including neurodegenerative disease, neurodevelopmental, and neuroplasticity studies. In this review we start with a brief introduction of myelin biology and discuss the contributions of myelin in conventional MRI contrasts. Then the MRI properties of myelin water and four different MWI methods, which are categorized as T2 -, T2 *-, T1 -, and steady-state-based MWI, are summarized. After that, we cover more practical issues such as availability, interpretation, and validation of these methods. To illustrate the utility of MWI as a clinical research tool, MWI studies for two diseases, multiple sclerosis and neuromyelitis optica, are introduced. Additional topics about imaging myelin in gray matter and non-MWI methods for myelin imaging are also included. Although technical and physiological limitations exist, MWI is a potent surrogate biomarker of myelin that carries valuable and useful information of myelin. Evidence Level: 5 Technical Efficacy: 1 J. MAGN. RESON. IMAGING 2021;53:360-373.
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Affiliation(s)
- Jongho Lee
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Jae-Won Hyun
- Department of Neurology, Research Institute and Hospital, National Cancer Center, Goyang-si, Korea
| | - Jieun Lee
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Eun-Jung Choi
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Hyeong-Geol Shin
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Kyeongseon Min
- Laboratory for Imaging Science and Technology, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Yoonho Nam
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea
| | - Ho Jin Kim
- Department of Neurology, Research Institute and Hospital, National Cancer Center, Goyang-si, Korea
| | - Se-Hong Oh
- Division of Biomedical Engineering, Hankuk University of Foreign Studies, Gyeonggi-do, Korea.,Imaging Institute, Cleveland Clinic, Cleveland, OH, USA
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33
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Drakesmith M, Harms R, Rudrapatna SU, Parker GD, Evans CJ, Jones DK. Estimating axon conduction velocity in vivo from microstructural MRI. Neuroimage 2019; 203:116186. [PMID: 31542512 PMCID: PMC6854468 DOI: 10.1016/j.neuroimage.2019.116186] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 11/19/2022] Open
Abstract
The conduction velocity (CV) of action potentials along axons is a key neurophysiological property central to neural communication. The ability to estimate CV in humans in vivo from non-invasive MRI methods would therefore represent a significant advance in neuroscience. However, there are two major challenges that this paper aims to address: (1) Much of the complexity of the neurophysiology of action potentials cannot be captured with currently available MRI techniques. Therefore, we seek to establish the variability in CV that can be captured when predicting CV purely from parameters that have been reported to be estimatable from MRI: inner axon diameter (AD) and g-ratio. (2) errors inherent in existing MRI-based biophysical models of tissue will propagate through to estimates of CV, the extent to which is currently unknown. Issue (1) is investigated by performing a sensitivity analysis on a comprehensive model of axon electrophysiology and determining the relative sensitivity to various morphological and electrical parameters. The investigations suggest that 85% of the variance in CV is accounted for by variation in AD and g-ratio. The observed dependency of CV on AD and g-ratio is well characterised by the previously reported model by Rushton. Issue (2) is investigated through simulation of diffusion and relaxometry MRI data for a range of axon morphologies, applying models of restricted diffusion and relaxation processes to derive estimates of axon volume fraction (AVF), AD and g-ratio and estimating CV from the derived parameters. The results show that errors in the AVF have the biggest detrimental impact on estimates of CV, particularly for sparse fibre populations (AVF<0.3). For our equipment set-up and acquisition protocol, CV estimates are most accurate (below 5% error) where AVF is above 0.3, g-ratio is between 0.6 and 0.85 and AD is high (above 4μm). CV estimates are robust to errors in g-ratio estimation but are highly sensitive to errors in AD estimation, particularly where ADs are small. We additionally show CV estimates in human corpus callosum in a small number of subjects. In conclusion, we demonstrate accurate CV estimates are possible in regions of the brain where AD is sufficiently large. Problems with estimating ADs for smaller axons presents a problem for estimating CV across the whole CNS and should be the focus of further study.
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Affiliation(s)
- Mark Drakesmith
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom; Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.
| | - Robbert Harms
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Suryanarayana Umesh Rudrapatna
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom; Phillips Inovation Campus, Bangalore, India
| | - Greg D Parker
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom; Experimental MRI Centre (EMRIC), School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - C John Evans
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom; Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Derek K Jones
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom; Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom; Mary McKillop Institute for Health Research, Faculty of Health Sciences, Australian Catholic University, Melbourne, Victoria, 3065, Australia
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34
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Quantitative age-dependent differences in human brainstem myelination assessed using high-resolution magnetic resonance mapping. Neuroimage 2019; 206:116307. [PMID: 31669302 DOI: 10.1016/j.neuroimage.2019.116307] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022] Open
Abstract
Previous in-vivo magnetic resonance imaging (MRI)-based studies of age-related differences in the human brainstem have focused on volumetric morphometry. These investigations have provided pivotal insights into regional brainstem atrophy but have not addressed microstructural age differences. However, growing evidence indicates the sensitivity of quantitative MRI to microstructural tissue changes in the brain. These studies have largely focused on the cerebrum, with very few MR investigations addressing age-dependent differences in the brainstem, in spite of its central role in the regulation of vital functions. Several studies indicate early brainstem alterations in a myriad of neurodegenerative diseases and dementias. The paucity of MR-focused investigations is likely due in part to the challenges imposed by the small structural scale of the brainstem itself as well as of substructures within, requiring accurate high spatial resolution imaging studies. In this work, we applied our recently developed approach to high-resolution myelin water fraction (MWF) mapping, a proxy for myelin content, to investigate myelin differences with normal aging within the brainstem. In this cross-sectional investigation, we studied a large cohort (n = 125) of cognitively unimpaired participants spanning a wide age range (21-94 years) and found a decrease in myelination with age in most brainstem regions studied, with several regions exhibiting a quadratic association between myelin and age. We believe that this study is the first investigation of MWF differences with normative aging in the adult brainstem. Further, our results provide reference MWF values.
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35
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Adult brain aging investigated using BMC-mcDESPOT-based myelin water fraction imaging. Neurobiol Aging 2019; 85:131-139. [PMID: 31735379 DOI: 10.1016/j.neurobiolaging.2019.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/30/2019] [Accepted: 10/07/2019] [Indexed: 01/23/2023]
Abstract
The relationship between regional brain myelination and aging has been the subject of intense study, with magnetic resonance imaging perhaps the most effective modality for elucidating this. However, most of these studies have used nonspecific methods to probe myelin content, including diffusion tensor imaging, magnetization transfer ratio, and relaxation times. In the present study, we used the BMC-mcDESPOT analysis, a direct and specific method for imaging of myelin water fraction (MWF), a surrogate of myelin content. We investigated age-related differences in MWF in several brain regions in a large cohort of cognitively unimpaired participants, spanning a wide age range. Our results indicate a quadratic, inverted U-shape, relationship between MWF and age in all brain regions investigated, suggesting that myelination continues until middle age followed by decreases at older ages. We also observed that these age-related differences vary across different brain regions, as expected. Our results provide evidence for nonlinear associations between age and myelin in a large sample of well-characterized adults, using a direct myelin content imaging method.
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36
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Liu H, Ljungberg E, Dvorak AV, Lee LE, Yik JT, MacMillan EL, Barlow L, Li DKB, Traboulsee A, Kolind SH, Kramer JLK, Laule C. Myelin Water Fraction and Intra/Extracellular Water Geometric Mean T 2 Normative Atlases for the Cervical Spinal Cord from 3T MRI. J Neuroimaging 2019; 30:50-57. [PMID: 31407400 DOI: 10.1111/jon.12659] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Acquiring and interpreting quantitative myelin-specific MRI data at an individual level is challenging because of technical difficulties and natural myelin variation in the population. To overcome these challenges, we used multiecho T2 myelin water imaging (MWI) to create T2 metric healthy population atlases that depict the mean and variation of myelin water fraction (MWF), and intra- and extracellular water mobility as described by geometric mean T2 (IEGMT2 ). METHODS Cervical cord MWI was performed at 3T on 20 healthy individuals (10M/10F, mean age: 36 years) and 3 relapsing remitting multiple sclerosis (RRMS) participants (1M/2F, age: 39/42/37 years). Anatomical data were collected for the purpose of image segmentation and registration. Atlases were created by coregistering and averaging T2 metrics from all controls. Voxel-wise z-score maps from 3 RRMS participants were produced to demonstrate the preliminary utility of the MWF and IEGMT2 atlases. RESULTS The average MWF atlas provides a representation of myelin in the spinal cord consistent with well-known spinal cord anatomical characteristics. The IEGMT2 atlas also depicted structural variations in the spinal cord. Z-score analysis illustrated distinct abnormalities in MWF and IEGMT2 in the 3 RRMS cases. CONCLUSIONS Our findings highlight the potential for using a quantitative T2 relaxation metric atlas to visualize and detect pathology in spinal cord. Our MWF and IEGMT2 atlases (URL: https://sourceforge.net/projects/mwi-spinal-cord-atlases/) can serve as normative references in the cervical spinal cord for other studies.
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Affiliation(s)
- Hanwen Liu
- Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - Adam V Dvorak
- Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Lisa Eunyoung Lee
- Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Jackie T Yik
- Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Erin L MacMillan
- Philips, Markham, Canada.,School of Mechatronic Systems Engineering, Simon Fraser University, Canada.,Department of Radiology, University of British Columbia, Vancouver, Canada
| | | | - David K B Li
- Department of Medicine, University of British Columbia, Vancouver, Canada.,Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Anthony Traboulsee
- Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Shannon H Kolind
- Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada.,Department of Medicine, University of British Columbia, Vancouver, Canada.,Department of Radiology, University of British Columbia, Vancouver, Canada
| | - John L K Kramer
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada.,School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Cornelia Laule
- Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada.,Department of Radiology, University of British Columbia, Vancouver, Canada.,Pathology & Laboratory Medicine, University of British Columbia, Vancouver, Canada
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