1
|
Gkotsoulias DG, Müller R, Jäger C, Schlumm T, Mildner T, Eichner C, Pampel A, Jaffe J, Gräßle T, Alsleben N, Chen J, Crockford C, Wittig R, Liu C, Möller HE. High angular resolution susceptibility imaging and estimation of fiber orientation distribution functions in primate brain. Neuroimage 2023; 276:120202. [PMID: 37247762 DOI: 10.1016/j.neuroimage.2023.120202] [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: 10/19/2022] [Revised: 05/21/2023] [Accepted: 05/27/2023] [Indexed: 05/31/2023] Open
Abstract
Uncovering brain-tissue microstructure including axonal characteristics is a major neuroimaging research focus. Within this scope, anisotropic properties of magnetic susceptibility in white matter have been successfully employed to estimate primary axonal trajectories using mono-tensorial models. However, anisotropic susceptibility has not yet been considered for modeling more complex fiber structures within a voxel, such as intersecting bundles, or an estimation of orientation distribution functions (ODFs). This information is routinely obtained by high angular resolution diffusion imaging (HARDI) techniques. In applications to fixed tissue, however, diffusion-weighted imaging suffers from an inherently low signal-to-noise ratio and limited spatial resolution, leading to high demands on the performance of the gradient system in order to mitigate these limitations. In the current work, high angular resolution susceptibility imaging (HARSI) is proposed as a novel, phase-based methodology to estimate ODFs. A multiple gradient-echo dataset was acquired in an entire fixed chimpanzee brain at 61 orientations by reorienting the specimen in the magnetic field. The constant solid angle method was adapted for estimating phase-based ODFs. HARDI data were also acquired for comparison. HARSI yielded information on whole-brain fiber architecture, including identification of peaks of multiple bundles that resembled features of the HARDI results. Distinct differences between both methods suggest that susceptibility properties may offer complementary microstructural information. These proof-of-concept results indicate a potential to study the axonal organization in post-mortem primate and human brain at high resolution.
Collapse
Affiliation(s)
- Dimitrios G Gkotsoulias
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Roland Müller
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Carsten Jäger
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Torsten Schlumm
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Toralf Mildner
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Cornelius Eichner
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - André Pampel
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Jennifer Jaffe
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Côte d'Ivoire
| | - Tobias Gräßle
- Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Côte d'Ivoire; Helmholtz Institute for One Health, Greifswald, Germany; Robert Koch Institute, Epidemiology of Highly Pathogenic Microorganisms, Berlin, Germany
| | - Niklas Alsleben
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Jingjia Chen
- Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Catherine Crockford
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Côte d'Ivoire; Institute of Cognitive Sciences, CNRS UMR5229 University of Lyon, Bron, France
| | - Roman Wittig
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Côte d'Ivoire; Institute of Cognitive Sciences, CNRS UMR5229 University of Lyon, Bron, France
| | - Chunlei Liu
- Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Harald E Möller
- Nuclear Magnetic Resonance Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| |
Collapse
|
2
|
Chen J, Gong NJ, Chaim KT, Otaduy MCG, Liu C. Decompose quantitative susceptibility mapping (QSM) to sub-voxel diamagnetic and paramagnetic components based on gradient-echo MRI data. Neuroimage 2021; 242:118477. [PMID: 34403742 PMCID: PMC8720043 DOI: 10.1016/j.neuroimage.2021.118477] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/13/2021] [Indexed: 12/31/2022] Open
Abstract
PURPOSE A method named DECOMPOSE-QSM is developed to decompose bulk susceptibility measured with QSM into sub-voxel paramagnetic and diamagnetic components based on a three-pool complex signal model. METHODS Multi-echo gradient echo signal is modeled as a summation of three weighted exponentials corresponding to three types of susceptibility sources: reference susceptibility, diamagnetic and paramagnetic susceptibility relative to the reference. Paramagnetic component susceptibility (PCS) and diamagnetic component susceptibility (DCS) maps are constructed to represent the sub-voxel compartments by solving for linear and nonlinear parameters in the model. RESULTS Numerical forward simulation and phantom validation confirmed the ability of DECOMPOSE-QSM to separate the mixture of paramagnetic and diamagnetic components. The PCS obtained from temperature-variant brainstem imaging follows the Curie's Law, which further validated the model and the solver. Initial in vivo investigation of human brain images showed the ability to extract sub-voxel PCS and DCS sources that produce visually enhanced contrast between brain structures comparing to threshold QSM.
Collapse
Affiliation(s)
- Jingjia Chen
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Nan-Jie Gong
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA; Vector Lab for Intelligent Medical Imaging and Neural Engineering, International Innovation Center of Tsinghua University, Shanghai, China
| | - Khallil Taverna Chaim
- LIM44, Instituto e Departamento de Radiologia, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | | | - Chunlei Liu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
| |
Collapse
|
3
|
Birkl C, Doucette J, Fan M, Hernández-Torres E, Rauscher A. Myelin water imaging depends on white matter fiber orientation in the human brain. Magn Reson Med 2020; 85:2221-2231. [PMID: 33017486 PMCID: PMC7821018 DOI: 10.1002/mrm.28543] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 09/13/2020] [Accepted: 09/14/2020] [Indexed: 12/14/2022]
Abstract
Purpose The multi‐exponential T2 decay of the MRI signal from cerebral white matter can be separated into short T2 components related to myelin water and long T2 components related to intracellular and extracellular water. In this study, we investigated to what degree the apparent myelin water fraction (MWF) depends on the angle between white matter fibers and the main magnetic field. Methods Maps of the apparent MWF were acquired using multi‐echo Carr‐Purcell‐Meiboom‐Gill and gradient‐echo spin‐echo sequences. The Carr‐Purcell‐Meiboom‐Gill sequence was acquired with a TR of 1073 ms, 1500 ms, and 2000 ms. The fiber orientation was mapped with DTI. By angle‐wise pooling the voxels across the brain’s white matter, orientation‐dependent apparent MWF curves were generated. Results We found that the apparent MWF varied between 25% and 35% across different fiber orientations. Furthermore, the selection of the TR influences the apparent MWF. Conclusion White matter fiber orientation induces a strong systematic bias on the estimation of the apparent MWF. This finding has implications for future research and the interpretation of MWI results in previously published studies.
Collapse
Affiliation(s)
- Christoph Birkl
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada.,Department of Neuroradiology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Neurology, Medical University of Graz, Graz, Austria
| | - Jonathan Doucette
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada.,Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada
| | - Michael Fan
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada.,Texas Oncology, Dallas, Texas, USA
| | - Enedino Hernández-Torres
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada.,Department of Medicine (Division of Neurology), University of British Columbia, Vancouver, Canada
| | - Alexander Rauscher
- UBC MRI Research Center, University of British Columbia, Vancouver, Canada.,Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.,Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, Canada
| |
Collapse
|
4
|
Kan H, Uchida Y, Arai N, Takizawa M, Miyati T, Kunitomo H, Kasai H, Shibamoto Y. Decreasing iron susceptibility with temperature in quantitative susceptibility mapping: A phantom study. Magn Reson Imaging 2020; 73:55-61. [PMID: 32853756 DOI: 10.1016/j.mri.2020.08.012] [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: 03/12/2020] [Revised: 07/03/2020] [Accepted: 08/20/2020] [Indexed: 01/04/2023]
Abstract
To clarify the temperature dependence of susceptibility estimated by quantitative susceptibility mapping (QSM) analysis, we investigated the relationship between temperature and susceptibility using a cylinder phantom with varying temperatures. Six solutions with various concentrations of superparamagnetic iron oxide (SPIO) nanoparticles were employed. These tubes were placed in a cylinder phantom and surrounded with water. The temperature of the circulated water was adjusted to change the temperature in the cylinder phantom from 25.8 °C to 42.5 °C. The cylinder phantom was scanned via a three-dimensional multiple spoiled gradient-echo sequence for R2* and QSM analyses with varying temperatures. The relationships between temperature, susceptibility, and R2* values were determined. Moreover, the temperature coefficients of susceptibility (χ-Tc) and (R2*-Tc) were calculated at each concentration and the linearities in these indices against each SPIO concentration were validated. Significant inverse correlations were found between temperature, susceptibility, and R2* values at each SPIO concentration due to the decrease in paramagnetic iron susceptibility that occurred with increasing temperature based on Curie's law. Moreover, although there were significant correlations between the susceptibility and R2* values at any temperature, the slopes of the regression lines grew in height with greater temperatures. The percentage of difference per Celsius degree in susceptibility in any SPIO concentration was lower than the corresponding finding among the R2* results. There were strong linearities between the SPIO concentration, χ-Tc (r = -0.994; p < 0.001), and R2*-Tc (r = -0.998; p < 0.001). The χ-Tc and R2*-Tc outcomes in a particular voxel varied considerably with the iron contents. Although there was an inverse correlation noted between temperature and susceptibility, the susceptibility analysis showed smaller temperature dependence relative to the R2* analysis. QSM analysis might be a more suitable option for magnetic resonance-based iron quantification in comparison with R2* relaxometry.
Collapse
Affiliation(s)
- Hirohito Kan
- Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Yuto Uchida
- Department of Neurology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan; Department of Neurology, Toyokawa City Hospital, 23 noji, Yahata-cho, Toyokawa, Aichi 442-8561, Japan
| | - Nobuyuki Arai
- Department of Radiology, Nagoya City University Hospital, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Masahiro Takizawa
- Healthcare Business Unit, Hitachi Ltd., 2-16-1 Higashi-Ueno, Daito-ku, Tokyo 110-0015, Japan.
| | - Tosiaki Miyati
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
| | - Hiroshi Kunitomo
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
| | - Harumasa Kasai
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
| | - Yuta Shibamoto
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| |
Collapse
|
5
|
Birkl C, Birkl-Toeglhofer AM, Kames C, Goessler W, Haybaeck J, Fazekas F, Ropele S, Rauscher A. The influence of iron oxidation state on quantitative MRI parameters in post mortem human brain. Neuroimage 2020; 220:117080. [PMID: 32585344 DOI: 10.1016/j.neuroimage.2020.117080] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022] Open
Abstract
A variety of Magnetic Resonance Imaging (MRI) techniques are known to be sensitive to brain iron content. In principle, iron sensitive MRI techniques are based on local magnetic field variations caused by iron particles in tissue. The purpose of this study was to investigate the sensitivity of MR relaxation and magnetization transfer parameters to changes in iron oxidation state compared to changes in iron concentration. Therefore, quantitative MRI parameters including R1, R2, R2∗, quantitative susceptibility maps (QSM) and magnetization transfer ratio (MTR) of post mortem human brain tissue were acquired prior and after chemical iron reduction to change the iron oxidation state and chemical iron extraction to decrease the total iron concentration. All assessed parameters were shown to be sensitive to changes in iron concentration whereas only R2, R2∗ and QSM were also sensitive to changes in iron oxidation state. Mass spectrometry confirmed that iron accumulated in the extraction solution but not in the reduction solution. R2∗ and QSM are often used as markers for iron content. Changes in these parameters do not necessarily reflect variations in iron content but may also be a result of changes in the iron's oxygenation state from ferric towards more ferrous iron or vice versa.
Collapse
Affiliation(s)
- Christoph Birkl
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Neuroradiology, Medical University of Innsbruck, Austria; Department of Neurology, Medical University of Graz, Austria.
| | - Anna Maria Birkl-Toeglhofer
- Department of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, Austria
| | - Christian Kames
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Walter Goessler
- Institute of Chemistry, Analytical Chemistry, University of Graz, Austria
| | - Johannes Haybaeck
- Department of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Austria
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada; Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
6
|
Masthoff M, Buchholz R, Beuker A, Wachsmuth L, Kraupner A, Albers F, Freppon F, Helfen A, Gerwing M, Höltke C, Hansen U, Rehkämper J, Vielhaber T, Heindel W, Eisenblätter M, Karst U, Wildgruber M, Faber C. Introducing Specificity to Iron Oxide Nanoparticle Imaging by Combining 57Fe-Based MRI and Mass Spectrometry. NANO LETTERS 2019; 19:7908-7917. [PMID: 31556617 DOI: 10.1021/acs.nanolett.9b03016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iron oxide nanoparticles (ION) are highly sensitive probes for magnetic resonance imaging (MRI) that have previously been used for in vivo cell tracking and have enabled implementation of several diagnostic tools to detect and monitor disease. However, the in vivo MRI signal of ION can overlap with the signal from endogenous iron, resulting in a lack of detection specificity. Therefore, the long-term fate of administered ION remains largely unknown, and possible tissue deposition of iron cannot be assessed with established methods. Herein, we combine nonradioactive 57Fe-ION MRI with ex vivo laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) imaging, enabling unambiguous differentiation between endogenous iron (56Fe) and iron originating from applied ION in mice. We establish 57Fe-ION as an in vivo MRI sensor for cell tracking in a mouse model of subcutaneous inflammation and for assessing the long-term fate of 57Fe-ION. Our approach resolves the lack of detection specificity in ION imaging by unambiguously recording a 57Fe signature.
Collapse
Affiliation(s)
- Max Masthoff
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Rebecca Buchholz
- Institute for Inorganic and Analytical Chemistry, University of Muenster , 48149 Muenster , Germany
| | - Andre Beuker
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Lydia Wachsmuth
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | | | - Franziska Albers
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Felix Freppon
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Anne Helfen
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Mirjam Gerwing
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Carsten Höltke
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Uwe Hansen
- Institute for Musculoskeletal Medicine , University Hospital Muenster , 48149 Muenster , Germany
| | - Jan Rehkämper
- Institute of Pathology , University Hospital Muenster , 48149 Muenster , Germany
| | - Torsten Vielhaber
- Institute for Inorganic and Analytical Chemistry, University of Muenster , 48149 Muenster , Germany
| | - Walter Heindel
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Michel Eisenblätter
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
| | - Uwe Karst
- Institute for Inorganic and Analytical Chemistry, University of Muenster , 48149 Muenster , Germany
- DFG Cluster of Excellence EXC 1003 "Cells in Motion" , University of Muenster , 48149 Muenster , Germany
| | - Moritz Wildgruber
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
- DFG Cluster of Excellence EXC 1003 "Cells in Motion" , University of Muenster , 48149 Muenster , Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Institute of Clinical Radiology , University Hospital Muenster , 48149 Muenster , Germany
- DFG Cluster of Excellence EXC 1003 "Cells in Motion" , University of Muenster , 48149 Muenster , Germany
| |
Collapse
|
7
|
De Barros A, Arribarat G, Combis J, Chaynes P, Péran P. Matching ex vivo MRI With Iron Histology: Pearls and Pitfalls. Front Neuroanat 2019; 13:68. [PMID: 31333421 PMCID: PMC6616088 DOI: 10.3389/fnana.2019.00068] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/19/2019] [Indexed: 12/12/2022] Open
Abstract
Iron levels in the brain can be estimated using newly developed specific magnetic resonance imaging (MRI) sequences. This technique has several applications, especially in neurodegenerative disorders like Alzheimer's disease or Parkinson's disease. Coupling ex vivo MRI with histology allows neuroscientists to better understand what they see in the images. Iron is one of the most extensively studied elements, both by MRI and using histological or physical techniques. Researchers were initially only able to make visual comparisons between MRI images and different types of iron staining, but the emergence of specific MRI sequences like R2* or quantitative susceptibility mapping meant that quantification became possible, requiring correlations with physical techniques. Today, with advances in MRI and image post-processing, it is possible to look for MRI/histology correlations by matching the two sorts of images. For the result to be acceptable, the choice of methodology is crucial, as there are hidden pitfalls every step of the way. In order to review the advantages and limitations of ex vivo MRI correlation with iron-based histology, we reviewed all the relevant articles dealing with the topic in humans. We provide separate assessments of qualitative and quantitative studies, and after summarizing the significant results, we emphasize all the pitfalls that may be encountered.
Collapse
Affiliation(s)
- Amaury De Barros
- Toulouse NeuroImaging Center, University of Toulouse Paul Sabatier-INSERM, Toulouse, France
- Department of Anatomy, Toulouse Faculty of Medicine, Toulouse, France
| | - Germain Arribarat
- Toulouse NeuroImaging Center, University of Toulouse Paul Sabatier-INSERM, Toulouse, France
| | - Jeanne Combis
- Toulouse NeuroImaging Center, University of Toulouse Paul Sabatier-INSERM, Toulouse, France
| | - Patrick Chaynes
- Department of Anatomy, Toulouse Faculty of Medicine, Toulouse, France
| | - Patrice Péran
- Toulouse NeuroImaging Center, University of Toulouse Paul Sabatier-INSERM, Toulouse, France
| |
Collapse
|
8
|
Kor D, Birkl C, Ropele S, Doucette J, Xu T, Wiggermann V, Hernández-Torres E, Hametner S, Rauscher A. The role of iron and myelin in orientation dependent R 2* of white matter. NMR IN BIOMEDICINE 2019; 32:e4092. [PMID: 31038240 DOI: 10.1002/nbm.4092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/05/2019] [Accepted: 02/17/2019] [Indexed: 06/09/2023]
Abstract
Brain myelin and iron content are important parameters in neurodegenerative diseases such as multiple sclerosis (MS). Both myelin and iron content influence the brain's R2* relaxation rate. However, their quantification based on R2* maps requires a realistic tissue model that can be fitted to the measured data. In structures with low myelin content, such as deep gray matter, R2* shows a linear increase with increasing iron content. In white matter, R2* is not only affected by iron and myelin but also by the orientation of the myelinated axons with respect to the external magnetic field. Here, we propose a numerical model which incorporates iron and myelin, as well as fibre orientation, to simulate R2* decay in white matter. Applying our model to fibre orientation-dependent in vivo R2* data, we are able to determine a unique solution of myelin and iron content in global white matter. We determine an averaged myelin volume fraction of 16.02 ± 2.07% in non-lesional white matter of patients with MS, 17.32 ± 2.20% in matched healthy controls, and 18.19 ± 2.98% in healthy siblings of patients with MS. Averaged iron content was 35.6 ± 8.9 mg/kg tissue in patients, 43.1 ± 8.3 mg/kg in controls, and 47.8 ± 8.2 mg/kg in siblings. All differences in iron content between groups were significant, while the difference in myelin content between MS patients and the siblings of MS patients was significant. In conclusion, we demonstrate that a model that combines myelin-induced orientation-dependent and iron-induced orientation-independent components is able to fit in vivo R2* data.
Collapse
Affiliation(s)
- Daniel Kor
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Christoph Birkl
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Jonathan Doucette
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Tianyou Xu
- Oxford Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Vanessa Wiggermann
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Enedino Hernández-Torres
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| | - Simon Hametner
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Alexander Rauscher
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
9
|
Birkl C, Birkl-Toeglhofer AM, Endmayr V, Höftberger R, Kasprian G, Krebs C, Haybaeck J, Rauscher A. The influence of brain iron on myelin water imaging. Neuroimage 2019; 199:545-552. [PMID: 31108214 DOI: 10.1016/j.neuroimage.2019.05.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 12/19/2022] Open
Abstract
With myelin playing a vital role in normal brain integrity and function and thus in various neurological disorders, myelin sensitive magnetic resonance imaging (MRI) techniques are of great importance. In particular, multi-exponential T2 relaxation was shown to be highly sensitive to myelin. The myelin water imaging (MWI) technique allows to separate the T2 decay into short components, specific to myelin water, and long components reflecting the intra- and extracellular water. The myelin water fraction (MWF) is the ratio of the short components to all components. In the brain's white matter (WM), myelin and iron are closely linked via the presence of iron in the myelin generating oligodendrocytes. Iron is known to decrease T2 relaxation times and may therefore mimic myelin. In this study, we investigated if variations in WM iron content can lead to apparent MWF changes. We performed MWI in post mortem human brain tissue prior and after chemical iron extraction. Histology for iron and myelin confirmed a decrease in iron content and no change in myelin content after iron extraction. In MRI, iron extraction lead to a decrease in MWF by 26%-28% in WM. Thus, a change in MWF does not necessarily reflect a change in myelin content. This observation has important implications for the interpretation of MWI findings in previously published studies and future research.
Collapse
Affiliation(s)
- Christoph Birkl
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Neurology, Medical University of Graz, Austria.
| | - Anna Maria Birkl-Toeglhofer
- Department of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, Austria
| | - Verena Endmayr
- Institute of Neurology, Medical University of Vienna, Austria
| | | | - Gregor Kasprian
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Claudia Krebs
- Department of Cellular & Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Johannes Haybaeck
- Department of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, Austria; Department of Pathology, Medical Faculty, Otto-von-Guerecke University Magdeburg, Germany
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada; Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada; Department of Pediatrics (Division of Neurology), University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
10
|
Dusek P, Madai VI, Huelnhagen T, Bahn E, Matej R, Sobesky J, Niendorf T, Acosta-Cabronero J, Wuerfel J. The choice of embedding media affects image quality, tissue R 2 * , and susceptibility behaviors in post-mortem brain MR microscopy at 7.0T. Magn Reson Med 2018; 81:2688-2701. [PMID: 30506939 DOI: 10.1002/mrm.27595] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 09/19/2018] [Accepted: 10/14/2018] [Indexed: 12/22/2022]
Abstract
PURPOSE The quality and precision of post-mortem MRI microscopy may vary depending on the embedding medium used. To investigate this, our study evaluated the impact of 5 widely used media on: (1) image quality, (2) contrast of high spatial resolution gradient-echo (T1 and T2 * -weighted) MR images, (3) effective transverse relaxation rate (R2 * ), and (4) quantitative susceptibility measurements (QSM) of post-mortem brain specimens. METHODS Five formaldehyde-fixed brain slices were scanned using 7.0T MRI in: (1) formaldehyde solution (formalin), (2) phosphate-buffered saline (PBS), (3) deuterium oxide (D2 O), (4) perfluoropolyether (Galden), and (5) agarose gel. SNR and contrast-to-noise ratii (SNR/CNR) were calculated for cortex/white matter (WM) and basal ganglia/WM regions. In addition, median R2 * and QSM values were extracted from caudate nucleus, putamen, globus pallidus, WM, and cortical regions. RESULTS PBS, Galden, and agarose returned higher SNR/CNR compared to formalin and D2 O. Formalin fixation, and its use as embedding medium for scanning, increased tissue R2 * . Imaging with agarose, D2 O, and Galden returned lower R2 * values than PBS (and formalin). No major QSM offsets were observed, although spatial variance was increased (with respect to R2 * behaviors) for formalin and agarose. CONCLUSIONS Embedding media affect gradient-echo image quality, R2 * , and QSM in differing ways. In this study, PBS embedding was identified as the most stable experimental setup, although by a small margin. Agarose and Galden were preferred to formalin or D2 O embedding. Formalin significantly increased R2 * causing noisier data and increased QSM variance.
Collapse
Affiliation(s)
- Petr Dusek
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic.,Department of Radiology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic
| | - Vince Istvan Madai
- Department of Neurology and Center for Stroke Research Berlin (CSB), Charité-Universitaetsmedizin, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Erik Bahn
- Institute of Neuropathology, University Medicine Göttingen, Göttingen, Germany
| | - Radoslav Matej
- Department of Pathology and Molecular Medicine, Thomayer Hospital, Praha, Czech Republic.,Department of Pathology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic
| | - Jan Sobesky
- Department of Neurology and Center for Stroke Research Berlin (CSB), Charité-Universitaetsmedizin, Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité-Universitaetsmedizin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Charité-Universitaetsmedizin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Julio Acosta-Cabronero
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.,German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Jens Wuerfel
- NeuroCure Clinical Research Center, Charité-Universitaetsmedizin, Berlin, Germany.,Medical Imaging Analysis Center AG, Basel, Switzerland.,Department of Biomedical Engineering, University Basel, Switzerland
| |
Collapse
|
11
|
Zhang Y, Shi J, Wei H, Han V, Zhu WZ, Liu C. Neonate and infant brain development from birth to 2 years assessed using MRI-based quantitative susceptibility mapping. Neuroimage 2018; 185:349-360. [PMID: 30315906 DOI: 10.1016/j.neuroimage.2018.10.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 09/10/2018] [Accepted: 10/09/2018] [Indexed: 12/23/2022] Open
Abstract
The human brain rapidly develops during the first two years following birth. Quantitative susceptibility mapping (QSM) provides information of iron and myelin variations. It is considered to be a valuable tool for studying brain development in early life. In the present work, QSM is performed on neonates, 1-year and 2-year old infants, as well as a group of adults for the purpose of reference. Age-specific templates representing common brain structures are built for each age group. The neonate and infant QSM templates have shown some unique findings compared to conventional T1w and T2w imaging techniques. The contrast between the gray and white matters on the QSM images did not change through brain development from neonate to adult. A linear correlation was found between brain myelination determined in this study and the microscopic myelin degree determined by a previous autopsy study. Also, the magnetic susceptibility values of the cerebral spinal fluid (CSF) exhibit a gradually decreasing trend from birth to 2 years old and to adulthood. The findings suggest that the macromolecular content, myelin, and iron may play the most important contributing factors for the magnetic susceptibility of neonate and infant brain. QSM can be a powerful means to study early brain development and related pathologies that involve alterations in macromolecular content, iron, or brain myelination.
Collapse
Affiliation(s)
- Yuyao Zhang
- School of Information and Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jingjing Shi
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongjiang Wei
- Electrical Engineering and Computer Science, University of California at Berkeley, CA, USA
| | - Victor Han
- Electrical Engineering and Computer Science, University of California at Berkeley, CA, USA
| | - Wen-Zhen Zhu
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Chunlei Liu
- Electrical Engineering and Computer Science, University of California at Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California at Berkeley, CA, USA.
| |
Collapse
|
12
|
Untangling the R2* contrast in multiple sclerosis: A combined MRI-histology study at 7.0 Tesla. PLoS One 2018; 13:e0193839. [PMID: 29561895 PMCID: PMC5862438 DOI: 10.1371/journal.pone.0193839] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 02/19/2018] [Indexed: 11/19/2022] Open
Abstract
T2*-weighted multi-echo gradient-echo magnetic resonance imaging and its reciprocal R2* are used in brain imaging due to their sensitivity to iron content. In patients with multiple sclerosis who display pathological alterations in iron and myelin contents, the use of R2* may offer a unique way to untangle mechanisms of disease. Coronal slices from 8 brains of deceased multiple sclerosis patients were imaged using a whole-body 7.0 Tesla MRI scanner. The scanning protocol included three-dimensional (3D) T2*-w multi-echo gradient-echo and 2D T2-w turbo spin echo (TSE) sequences. Histopathological analyses of myelin and iron content were done using Luxol fast blue and proteolipid myelin staining and 3,3′-diaminobenzidine tetrahydrochloride enhanced Turnbull blue staining. Quantification of R2*, myelin and iron intensity were obtained. Variations in R2* were found to be affected differently by myelin and iron content in different regions of multiple sclerosis brains. The data shall inform clinical investigators in addressing the role of T2*/R2* variations as a biomarker of tissue integrity in brains of MS patients, in vivo.
Collapse
|
13
|
Birkl C, Carassiti D, Hussain F, Langkammer C, Enzinger C, Fazekas F, Schmierer K, Ropele S. Assessment of ferritin content in multiple sclerosis brains using temperature-induced R* 2 changes. Magn Reson Med 2018; 79:1609-1615. [PMID: 28618066 DOI: 10.1002/mrm.26780] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/13/2017] [Accepted: 05/13/2017] [Indexed: 12/23/2022]
Abstract
PURPOSE Current MRI techniques cannot reliably assess iron content in white matter due to the confounding diamagnetic effect of myelin. The purpose of this study was to validate with histology a novel iron mapping technique that uses the temperature dependency of the paramagnetic susceptibility in multiple sclerosis (MS) brains, where white matter has been reported to show significant variations in iron content. METHODS We investigated post mortem brain tissue from three MS patients and one control subject. Temperature-dependent R2* relaxometry was performed between 4°C and 37°C. The resulting temperature coefficient ( TcR2*) maps were compared with immunohistochemical stains for ferritin light chain. RESULTS Good agreement between TcR2* maps and ferritin staining was found by way of visual comparison and quantitative analysis. The highest iron concentrations were detected at the edge of MS lesions and in the basal ganglia. For all regions, except the subcortical U-fibers, there was a significant negative correlation between the TcR2* values and the ferritin count. CONCLUSION This study provides further evidence that TcR2* may be a reliable measure of white matter iron content due to the elimination of myelin-induced susceptibility changes and is well suited for further research into neurological diseases with distortions of the iron homeostasis. Magn Reson Med 79:1609-1615, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Christoph Birkl
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Daniele Carassiti
- Blizard Institute (Neuroscience), Queen Mary, University of London, London, United Kingdom
| | - Fariha Hussain
- Blizard Institute (Neuroscience), Queen Mary, University of London, London, United Kingdom
| | | | | | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Klaus Schmierer
- Blizard Institute (Neuroscience), Queen Mary, University of London, London, United Kingdom.,Barts Health NHS Trust, Emergency Care and Acute Medicine Neuroscience Clinical Academic Group, London, United Kingdom
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
| |
Collapse
|
14
|
Birkl C, Soellradl M, Toeglhofer AM, Krassnig S, Leoni M, Pirpamer L, Vorauer T, Krenn H, Haybaeck J, Fazekas F, Ropele S, Langkammer C. Effects of concentration and vendor specific composition of formalin on postmortem MRI of the human brain. Magn Reson Med 2018; 79:1111-1115. [PMID: 28382642 DOI: 10.1002/mrm.26699] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/13/2017] [Accepted: 03/13/2017] [Indexed: 01/31/2023]
Abstract
PURPOSE Formalin fixation prevents tissue autolysis by crosslinking proteins and changes tissue microstructure and MRI signal characteristics. Previous studies showed high variations in MR relaxation time constants of formalin fixed brain tissue, which has been attributed to the use of different formalin concentrations. Our investigations confirmed the influence of formalin concentration on relaxation times and unexpectedly revealed an influence of vendor specific formalin composition, which has not been investigated so far. METHODS We systematically analyzed relaxation times of human brain tissue fixed with 4% and 10% formalin compared with unfixed condition at 3 Tesla MRI. Furthermore, we assessed relaxation times of nine formalin solutions from different vendors and performed comparisons of their magnetic susceptibility by SQUID (superconducting quantum interference device) magnetometry. RESULTS Tissue relaxation times decreased approximately twice as fast using 10% than in 4% formalin fixation. The vendor specific composition of the formalin solutions and concentration dependent paramagnetic effects showed a substantial contribution to differences in relaxation times of formalin. CONCLUSION Our study demonstrates that differences of the formalin composition have substantial effects on MRI signal characteristics after fixation, which can explain the divergence of reported relaxation times beyond the effect of differences in formalin concentration. Magn Reson Med 79:1111-1115, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Christoph Birkl
- Department of Neurology, Medical University of Graz, Austria
| | | | - Anna Maria Toeglhofer
- Department of Neuropathology, Institute of Pathology, Medical University of Graz, Austria
| | - Stefanie Krassnig
- Department of Neuropathology, Institute of Pathology, Medical University of Graz, Austria
| | - Marlene Leoni
- Department of Neuropathology, Institute of Pathology, Medical University of Graz, Austria
| | - Lukas Pirpamer
- Department of Neurology, Medical University of Graz, Austria
| | - Thomas Vorauer
- Institute of Physics, Experimental Physics, University of Graz, Austria
| | - Heinz Krenn
- Institute of Physics, Experimental Physics, University of Graz, Austria
| | - Johannes Haybaeck
- Department of Neuropathology, Institute of Pathology, Medical University of Graz, Austria.,Department of Pathology, Medical Faculty, Otto-von-Guericke-University, Magdeburg, Germany
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Austria
| | | |
Collapse
|
15
|
Abstract
Susceptibility Weighted Imaging (SWI) is an established part of the clinical neuroimaging toolbox and, since its inception, has also successfully been used in various preclinical studies. Exploiting the effect of variations of magnetic susceptibility between different tissues on the externally applied, static, homogeneous magnetic field, the method visualizes venous vasculature, hemorrhages and blood degradation products, calcifications, and tissue iron deposits. The chapter describes in vivo and ex vivo protocols for preclinical SWI in rodents.
Collapse
Affiliation(s)
- Ferdinand Schweser
- Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA.
- Center for Biomedical Imaging, Clinical and Translational Science Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA.
| | - Marilena Preda
- Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
- Center for Biomedical Imaging, Clinical and Translational Science Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
- Center for Biomedical Imaging, Clinical and Translational Science Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA
| |
Collapse
|
16
|
Gattringer T, Khalil M, Langkammer C, Pinter D, Ropele S, Fazekas F, Enzinger C. Comment on the letter to the editor entitled “Brain iron deposition in patients with white matter hyperintensities of presumed vascular origin” by D. Zhou. Neurobiol Aging 2017; 53:198. [DOI: 10.1016/j.neurobiolaging.2016.09.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 09/30/2016] [Indexed: 11/28/2022]
|
17
|
Ropele S, Langkammer C. Iron quantification with susceptibility. NMR IN BIOMEDICINE 2017; 30:e3534. [PMID: 27119601 DOI: 10.1002/nbm.3534] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/19/2016] [Accepted: 03/11/2016] [Indexed: 05/26/2023]
Abstract
Iron is an essential trace element involved in a variety of biological mechanisms in the human body. Disturbances of iron homeostasis have been observed in several inflammatory and degenerative diseases, which have raised strong interest in non-invasive iron mapping techniques. Numerous MRI techniques have been proposed so far, mostly based on the field changes induced by the magnetic properties of iron. Each of these approaches has a specific sensitivity for iron and its microstructural environment. Quantitative susceptibility mapping is the latest development and provides a direct measure of bulk susceptibility. However, field changes induced by iron are not always directly related to the concentration of iron, but rather reflect the structure of iron compounds and its cellular distribution. This review provides an overview of the most relevant iron compounds in the human body, their magnetic properties and their cellular distribution. In addition, MRI methods based on direct or indirect susceptibility changes are presented and discussed with respect to technical aspects and clinical applicability. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
| | | |
Collapse
|
18
|
Abstract
Increased iron deposition in cerebral deep gray matter has been considered a global marker for neurodegeneration in multiple sclerosis (MS); it scales with disease duration and severity. Iron accumulation in white matter and MS lesions might be more directly related to disease activity and has been discussed as a contributor to the inflammatory and neurodegenerative cascade. New insights into iron and MS are expected from MR imaging. We discuss findings from MR iron mapping proposed. Because of the confounding magnetic properties of myelin, iron mapping in white matter remains an unresolved issue.
Collapse
|
19
|
Uddin MN, Lebel RM, Wilman AH. Value of transverse relaxometry difference methods for iron in human brain. Magn Reson Imaging 2016; 34:51-9. [DOI: 10.1016/j.mri.2015.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 05/06/2015] [Accepted: 09/11/2015] [Indexed: 01/14/2023]
|
20
|
Augustinack JC, van der Kouwe AJW. Postmortem imaging and neuropathologic correlations. HANDBOOK OF CLINICAL NEUROLOGY 2016; 136:1321-39. [PMID: 27430472 DOI: 10.1016/b978-0-444-53486-6.00069-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Postmortem imaging refers to scanning autopsy specimens using magnetic resonance imaging (MRI) or optical imaging. This chapter summarizes postmortem imaging and its usefulness in brain mapping. Standard in vivo MRI has limited resolution due to time constraints and does not deliver cortical boundaries (e.g., Brodmann areas). Postmortem imaging offers a means to obtain ultra-high-resolution images with appropriate contrast for delineating cortical regions. Postmortem imaging provides the ability to validate MRI properties against histologic stained sections. This approach has enabled probabilistic mapping that is based on ex vivo MRI contrast, validated to histology, and subsequently mapped on to an in vivo model. This chapter emphasizes structural imaging, which can be validated with histologic assessment. Postmortem imaging has been applied to neuropathologic studies as well. This chapter includes many ex vivo studies, but focuses on studies of the medial temporal lobe, often involved in neurologic disease. New research using optical imaging is also highlighted.
Collapse
Affiliation(s)
- Jean C Augustinack
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.
| | - André J W van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| |
Collapse
|