1
|
Kuo DP, Chen YC, Cheng SJ, Hsieh KLC, Ou CY, Li YT, Chen CY. Ischemia-reperfusion injury in a salvaged penumbra: Longitudinal high-tesla perfusion magnetic resonance imaging in a rat model. Magn Reson Imaging 2024; 112:47-53. [PMID: 38909765 DOI: 10.1016/j.mri.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/23/2024] [Accepted: 06/20/2024] [Indexed: 06/25/2024]
Abstract
INTRODUCTION Although ischemia-reperfusion (I/R) injury varies between cortical and subcortical regions, its effects on specific regions remain unclear. In this study, we used various magnetic resonance imaging (MRI) techniques to examine the spatiotemporal dynamics of I/R injury within the salvaged ischemic penumbra (IP) and reperfused ischemic core (IC) of a rodent model, with the aim of enhancing therapeutic strategies by elucidating these dynamics. MATERIALS AND METHODS A total of 17 Sprague-Dawley rats were subjected to 1 h of transient middle cerebral artery occlusion with a suture model. MRI, including diffusion tensor imaging (DTI), T2-weighted imaging, perfusion-weighted imaging, and T1 mapping, was conducted at multiple time points for up to 5 days during the I/R phases. The spatiotemporal dynamics of blood-brain barrier (BBB) modifications were characterized through changes in T1 within the IP and IC regions and compared with mean diffusivity (MD), T2, and cerebral blood flow. RESULTS During the I/R phases, the MD of the IC initially decreased, normalized after recanalization, decreased again at 24 h, and peaked on day 5. By contrast, the IP remained relatively stable. Both the IP and IC exhibited hyperperfusion, with the IP reaching its peak at 24 h, followed by resolution, whereas hyperperfusion was maintained in the IC until day 5. Despite hyperperfusion, the IP maintained an intact BBB, whereas the IC experienced persistent BBB leakage. At 24 h, the IC exhibited an increase in the T2 signal, corresponding to regions exhibiting BBB disruption at 5 days. CONCLUSIONS Hyperperfusion and BBB impairment have distinct patterns in the IP and IC. Quantitative T1 mapping may serve as a supplementary tool for the early detection of malignant hyperemia accompanied by BBB leakage, aiding in precise interventions after recanalization. These findings underscore the value of MRI markers in monitoring ischemia-specific regions and customizing therapeutic strategies to improve patient outcomes.
Collapse
Affiliation(s)
- Duen-Pang Kuo
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sho-Jen Cheng
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Kevin Li-Chun Hsieh
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chen-Yin Ou
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Yi-Tien Li
- Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Research Center for Neuroscience, Taipei Medical University, Taipei, Taiwan; Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Research Center for Artificial Intelligence in Medicine, Taipei Medical University, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Radiology, National Defense Medical Center, Taipei, Taiwan
| |
Collapse
|
2
|
Singer R, Oganezova I, Hu W, Liu L, Ding Y, de Groot HJM, Spaink HP, Alia A. Ultrahigh field diffusion magnetic resonance imaging uncovers intriguing microstructural changes in the adult zebrafish brain caused by Toll-like receptor 2 genomic deletion. NMR IN BIOMEDICINE 2024:e5170. [PMID: 38742727 DOI: 10.1002/nbm.5170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 05/16/2024]
Abstract
Toll-like receptor 2 (TLR2) belongs to the TLR protein family that plays an important role in the immune and inflammation response system. While TLR2 is predominantly expressed in immune cells, its expression has also been detected in the brain, specifically in microglia and astrocytes. Recent studies indicate that genomic deletion of TLR2 can result in impaired neurobehavioural function. It is currently not clear if the genomic deletion of TLR2 leads to any alterations in the microstructural features of the brain. In the current study, we noninvasively assess microstructural changes in the brain of TLR2-deficient (tlr2-/-) zebrafish using state-of-the art magnetic resonance imaging (MRI) methods at ultrahigh magnetic field strength (17.6 T). A significant increase in cortical thickness and an overall trend towards increased brain volumes were observed in young tlr2-/- zebrafish. An elevated T2 relaxation time and significantly reduced apparent diffusion coefficient (ADC) unveil brain-wide microstructural alterations, potentially indicative of cytotoxic oedema and astrogliosis in the tlr2-/- zebrafish. Multicomponent analysis of the ADC diffusivity signal by the phasor approach shows an increase in the slow ADC component associated with restricted diffusion. Diffusion tensor imaging and diffusion kurtosis imaging analysis revealed diminished diffusivity and enhanced kurtosis in various white matter tracks in tlr2-/- compared with control zebrafish, identifying the microstructural underpinnings associated with compromised white matter integrity and axonal degeneration. Taken together, our findings demonstrate that the genomic deletion of TLR2 results in severe alterations to the microstructural features of the zebrafish brain. This study also highlights the potential of ultrahigh field diffusion MRI techniques in discerning exceptionally fine microstructural details within the small zebrafish brain, offering potential for investigating microstructural changes in zebrafish models of various brain diseases.
Collapse
Affiliation(s)
- Rico Singer
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Ina Oganezova
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Wanbin Hu
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Li Liu
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Yi Ding
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Huub J M de Groot
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - A Alia
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Institute of Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
| |
Collapse
|
3
|
Hiyoshi T, Zhao F, Baba R, Hirakawa T, Kuboki R, Suzuki K, Tomimatsu Y, O'Donnell P, Han S, Zach N, Nakashima M. Electrical impedance myography detects dystrophin-related muscle changes in mdx mice. Skelet Muscle 2023; 13:19. [PMID: 37980539 PMCID: PMC10657153 DOI: 10.1186/s13395-023-00331-1] [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: 08/29/2023] [Accepted: 10/27/2023] [Indexed: 11/20/2023] Open
Abstract
BACKGROUND The lack of functional dystrophin protein in Duchenne muscular dystrophy (DMD) causes chronic skeletal muscle inflammation and degeneration. Therefore, the restoration of functional dystrophin levels is a fundamental approach for DMD therapy. Electrical impedance myography (EIM) is an emerging tool that provides noninvasive monitoring of muscle conditions and has been suggested as a treatment response biomarker in diverse indications. Although magnetic resonance imaging (MRI) of skeletal muscles has become a standard measurement in clinical trials for DMD, EIM offers distinct advantages, such as portability, user-friendliness, and reduced cost, allowing for remote monitoring of disease progression or response to therapy. To investigate the potential of EIM as a biomarker for DMD, we compared longitudinal EIM data with MRI/histopathological data from an X-linked muscular dystrophy (mdx) mouse model of DMD. In addition, we investigated whether EIM could detect dystrophin-related changes in muscles using antisense-mediated exon skipping in mdx mice. METHODS The MRI data for muscle T2, the magnetic resonance spectroscopy (MRS) data for fat fraction, and three EIM parameters with histopathology were longitudinally obtained from the hindlimb muscles of wild-type (WT) and mdx mice. In the EIM study, a cell-penetrating peptide (Pip9b2) conjugated antisense phosphorodiamidate morpholino oligomer (PPMO), designed to induce exon-skipping and restore functional dystrophin production, was administered intravenously to mdx mice. RESULTS MRI imaging in mdx mice showed higher T2 intensity at 6 weeks of age in hindlimb muscles compared to WT mice, which decreased at ≥ 9 weeks of age. In contrast, EIM reactance began to decline at 12 weeks of age, with peak reduction at 18 weeks of age in mdx mice. This decline was associated with myofiber atrophy and connective tissue infiltration in the skeletal muscles. Repeated dosing of PPMO (10 mg/kg, 4 times every 2 weeks) in mdx mice led to an increase in muscular dystrophin protein and reversed the decrease in EIM reactance. CONCLUSIONS These findings suggest that muscle T2 MRI is sensitive to the early inflammatory response associated with dystrophin deficiency, whereas EIM provides a valuable biomarker for the noninvasive monitoring of subsequent changes in skeletal muscle composition. Furthermore, EIM reactance has the potential to monitor dystrophin-deficient muscle abnormalities and their recovery in response to antisense-mediated exon skipping.
Collapse
Affiliation(s)
- Tetsuaki Hiyoshi
- Neuroscience Translational Medicine, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Fuqiang Zhao
- Center of Excellence for Imaging, Preclinical and Translational Sciences, Takeda Development Center Americas, Inc., 95 Hayden Avenue, Lexington, MA, 02141, USA
| | - Rina Baba
- Muscular Disease and Neuropathy Unit, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Takeshi Hirakawa
- Muscular Disease and Neuropathy Unit, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Ryosuke Kuboki
- Muscular Disease and Neuropathy Unit, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Kazunori Suzuki
- Muscular Disease and Neuropathy Unit, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Yoshiro Tomimatsu
- Neuroscience Translational Medicine, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | - Patricio O'Donnell
- Neuroscience Translational Medicine, Neuroscience Drug Discovery Unit, Takeda Development Center Americas, Inc., 95 Hayden Avenue, Lexington, MA, 02141, USA
| | - Steve Han
- Neuroscience Therapeutic Area Unit, Takeda Development Center Americas, Inc., 95 Hayden Avenue, Lexington, MA, 02141, USA
| | - Neta Zach
- Neuroscience Translational Medicine, Neuroscience Drug Discovery Unit, Takeda Development Center Americas, Inc., 95 Hayden Avenue, Lexington, MA, 02141, USA
| | - Masato Nakashima
- Neuroscience Translational Medicine, Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan.
| |
Collapse
|
4
|
Moyaert P, Padrela BE, Morgan CA, Petr J, Versijpt J, Barkhof F, Jurkiewicz MT, Shao X, Oyeniran O, Manson T, Wang DJJ, Günther M, Achten E, Mutsaerts HJMM, Anazodo UC. Imaging blood-brain barrier dysfunction: A state-of-the-art review from a clinical perspective. Front Aging Neurosci 2023; 15:1132077. [PMID: 37139088 PMCID: PMC10150073 DOI: 10.3389/fnagi.2023.1132077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/15/2023] [Indexed: 05/05/2023] Open
Abstract
The blood-brain barrier (BBB) consists of specialized cells that tightly regulate the in- and outflow of molecules from the blood to brain parenchyma, protecting the brain's microenvironment. If one of the BBB components starts to fail, its dysfunction can lead to a cascade of neuroinflammatory events leading to neuronal dysfunction and degeneration. Preliminary imaging findings suggest that BBB dysfunction could serve as an early diagnostic and prognostic biomarker for a number of neurological diseases. This review aims to provide clinicians with an overview of the emerging field of BBB imaging in humans by answering three key questions: (1. Disease) In which diseases could BBB imaging be useful? (2. Device) What are currently available imaging methods for evaluating BBB integrity? And (3. Distribution) what is the potential of BBB imaging in different environments, particularly in resource limited settings? We conclude that further advances are needed, such as the validation, standardization and implementation of readily available, low-cost and non-contrast BBB imaging techniques, for BBB imaging to be a useful clinical biomarker in both resource-limited and well-resourced settings.
Collapse
Affiliation(s)
- Paulien Moyaert
- Department of Medical Imaging, Ghent University Hospital, Ghent, Belgium
- Lawson Health Research Institute, London, ON, Canada
- Department of Neurology, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
- *Correspondence: Paulien Moyaert,
| | - Beatriz E. Padrela
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, Netherlands
| | - Catherine A. Morgan
- School of Psychology and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
- Centre for Advanced MRI, Auckland UniServices Limited, Auckland, New Zealand
| | - Jan Petr
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, Netherlands
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany
| | - Jan Versijpt
- Department of Neurology, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Frederik Barkhof
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, Netherlands
- Queen Square Institute of Neurology and Centre for Medical Image Computing, University College London, London, United Kingdom
| | | | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Olujide Oyeniran
- Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
| | - Tabitha Manson
- Centre for Advanced MRI, Auckland UniServices Limited, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Danny J. J. Wang
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Matthias Günther
- Fraunhofer Institute for Digital Medicine, University of Bremen, Bremen, Germany
| | - Eric Achten
- Department of Medical Imaging, Ghent University Hospital, Ghent, Belgium
| | - Henk J. M. M. Mutsaerts
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, Netherlands
| | - Udunna C. Anazodo
- Lawson Health Research Institute, London, ON, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| |
Collapse
|
5
|
Ohene Y, Harrison IF, Nahavandi P, Ismail O, Bird EV, Ottersen OP, Nagelhus EA, Thomas DL, Lythgoe MF, Wells JA. Non-invasive MRI of brain clearance pathways using multiple echo time arterial spin labelling: an aquaporin-4 study. Neuroimage 2018; 188:515-523. [PMID: 30557661 PMCID: PMC6414399 DOI: 10.1016/j.neuroimage.2018.12.026] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/30/2018] [Accepted: 12/12/2018] [Indexed: 12/26/2022] Open
Abstract
There is currently a lack of non-invasive tools to assess water transport in healthy and pathological brain tissue. Aquaporin-4 (AQP4) water channels are central to many water transport mechanisms, and emerging evidence also suggests that AQP4 plays a key role in amyloid-β (Aβ) clearance, possibly via the glymphatic system. Here, we present the first non-invasive technique sensitive to AQP4 channels polarised at the blood-brain interface (BBI). We apply a multiple echo time (multi-TE) arterial spin labelling (ASL) MRI technique to the mouse brain to assess BBI water permeability via calculation of the exchange time (Texw), the time for magnetically labelled intravascular water to exchange across the BBI. We observed a 31% increase in exchange time in AQP4-deficient (Aqp4-/-) mice (452 ± 90 ms) compared to their wild-type counterparts (343 ± 91 ms) (p = 0.01), demonstrating the sensitivity of the technique to the lack of AQP4 water channels. More established, quantitative MRI parameters: arterial transit time (δa), cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) detected no significant changes with the removal of AQP4. This clinically relevant tool may be crucial to better understand the role of AQP4 in water transport across the BBI, as well as clearance of proteins in neurodegenerative conditions such as Alzheimer's disease.
Collapse
Affiliation(s)
- Yolanda Ohene
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Ian F Harrison
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Payam Nahavandi
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Ozama Ismail
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Eleanor V Bird
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Ole P Ottersen
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Erlend A Nagelhus
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - David L Thomas
- Neuroradiological Academic Unit, UCL Institute of Neurology, UCL, London, UK; Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology, UCL, London, UK
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK
| | - Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, UK.
| |
Collapse
|
6
|
Behroozi M, Chwiesko C, Ströckens F, Sauvage M, Helluy X, Peterburs J, Güntürkün O. In vivo measurement of T 1 and T 2 relaxation times in awake pigeon and rat brains at 7T. Magn Reson Med 2017; 79:1090-1100. [PMID: 28474481 DOI: 10.1002/mrm.26722] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE Establishment of regional longitudinal (T1 ) and transverse (T2 ) relaxation times in awake pigeons and rats at 7T field strength. Regional differences in relaxation times between species and between two different pigeon breeds (homing pigeons and Figurita pigeons) were investigated. METHODS T1 and T2 relaxation times were determined for nine functionally equivalent brain regions in awake pigeons and rats using a multiple spin-echo saturation recovery method with variable repetition time and a multi-slice/multi-echo sequence, respectively. Optimized head fixation and habituation protocols were applied to accustom animals to the scanning conditions and to minimize movement. RESULTS The habituation protocol successfully limited movement of the awake animals to a negligible minimum, allowing reliable measurement of T1 and T2 values within all regions of interest. Significant differences in relaxation times were found between rats and pigeons but not between different pigeon breeds. CONCLUSION The obtained T1 and T2 values for awake pigeons and rats and the optimized habituation protocol will augment future MRI studies with awake animals. The differences in relaxation times observed between species underline the importance of the acquisition of T1 /T2 values as reference points for specific experiments. Magn Reson Med 79:1090-1100, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Mehdi Behroozi
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Bochum, Germany
| | - Caroline Chwiesko
- Mercator Research Group, Ruhr-University Bochum, Bochum, Germany
- Leibniz Institute for Neurobiology, Functional Architecture of Memory Department, Magdeburg, Germany
- Faculty of Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Felix Ströckens
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Bochum, Germany
| | - Magdalena Sauvage
- Mercator Research Group, Ruhr-University Bochum, Bochum, Germany
- Leibniz Institute for Neurobiology, Functional Architecture of Memory Department, Magdeburg, Germany
- Faculty of Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Xavier Helluy
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Bochum, Germany
- Department of Neurophysiology, Faculty of Medicine, Ruhr-University Bochum, Bochum, Germany
| | - Jutta Peterburs
- Division of Cognitive Neuroscience, Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Onur Güntürkün
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Bochum, Germany
- Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, South Africa
| |
Collapse
|
7
|
Khajehim M, Nasiraei Moghaddam A. Investigating the spatial specificity of S2-SSFP fMRI: A Monte Carlo simulation approach. Magn Reson Imaging 2017; 37:282-289. [DOI: 10.1016/j.mri.2016.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 11/29/2022]
|
8
|
Pastor G, Jiménez-González M, Plaza-García S, Beraza M, Reese T. Fast T1 and T2 mapping methods: the zoomed U-FLARE sequence compared with EPI and snapshot-FLASH for abdominal imaging at 11.7 Tesla. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:299-307. [DOI: 10.1007/s10334-016-0604-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
|
9
|
Naumova AV, Akulov AE, Khodanovich MY, Yarnykh VL. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields. Neuroimage 2016; 147:985-993. [PMID: 27646128 DOI: 10.1016/j.neuroimage.2016.09.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/14/2016] [Accepted: 09/16/2016] [Indexed: 11/24/2022] Open
Abstract
A well-known problem in ultra-high-field MRI is generation of high-resolution three-dimensional images for detailed characterization of white and gray matter anatomical structures. T1-weighted imaging traditionally used for this purpose suffers from the loss of contrast between white and gray matter with an increase of magnetic field strength. Macromolecular proton fraction (MPF) mapping is a new method potentially capable to mitigate this problem due to strong myelin-based contrast and independence of this parameter of field strength. MPF is a key parameter determining the magnetization transfer effect in tissues and defined within the two-pool model as a relative amount of macromolecular protons involved into magnetization exchange with water protons. The objectives of this study were to characterize the two-pool model parameters in brain tissues in ultra-high magnetic fields and introduce fast high-field 3D MPF mapping as both anatomical and quantitative neuroimaging modality for small animal applications. In vivo imaging data were obtained from four adult male rats using an 11.7T animal MRI scanner. Comprehensive comparison of brain tissue contrast was performed for standard R1 and T2 maps and reconstructed from Z-spectroscopic images two-pool model parameter maps including MPF, cross-relaxation rate constant, and T2 of pools. Additionally, high-resolution whole-brain 3D MPF maps were obtained with isotropic 170µm voxel size using the single-point synthetic-reference method. MPF maps showed 3-6-fold increase in contrast between white and gray matter compared to other parameters. MPF measurements by the single-point synthetic reference method were in excellent agreement with the Z-spectroscopic method. MPF values in rat brain structures at 11.7T were similar to those at lower field strengths, thus confirming field independence of MPF. 3D MPF mapping provides a useful tool for neuroimaging in ultra-high magnetic fields enabling both quantitative tissue characterization based on the myelin content and high-resolution neuroanatomical visualization with high contrast between white and gray matter.
Collapse
Affiliation(s)
- Anna V Naumova
- University of Washington, Department of Radiology, 850 Republican Street, Seattle, WA, USA; National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Avenue, Tomsk, Russia
| | - Andrey E Akulov
- Institute of Cytology and Genetics, The Siberian Branch of the Russian Academy of Sciences, 10 Lavrentyeva Avenue, Novosibirsk, Russia
| | - Marina Yu Khodanovich
- National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Avenue, Tomsk, Russia
| | - Vasily L Yarnykh
- University of Washington, Department of Radiology, 850 Republican Street, Seattle, WA, USA; National Research Tomsk State University, Research Institute of Biology and Biophysics, 36 Lenina Avenue, Tomsk, Russia.
| |
Collapse
|
10
|
Walton JH, Ng KF, Anderson SE, Rutledge JC. MRI measurement of blood-brain barrier transport with a rapid acquisition refocused echo (RARE) method. Biochem Biophys Res Commun 2015; 463:479-82. [PMID: 25998382 DOI: 10.1016/j.bbrc.2015.05.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/10/2015] [Indexed: 10/23/2022]
Abstract
Dynamic Contrast Enhanced (DCE) MRI is increasingly being used to assess changes in capillary permeability. Most quantitative techniques used to measure capillary permeability are based on the Fick equation that requires measurement of signal reflecting both plasma and tissue concentrations of the solute being tested. To date, most Magnetic Resonance Imaging (MRI) methods for acquiring appropriate data quickly rely on gradient recalled echo (GRE) type acquisitions, which work well in clinical low field settings. However, acquiring this type of data on high field small animal preclinical MRIs is problematic due to geometrical distortions from susceptibility mismatch. This problem can be exacerbated when using small animal models to measure blood brain barrier (BBB) permeability, where precise sampling from the superior sagittal sinus (SSS) is commonly used to determine the plasma concentration of the contrast agent. Here we present results demonstrating that a standard saturation recovery rapid acquisition refocused echo (RARE) method is capable of acquiring T1 maps with good spatial and temporal resolution for Patlak analysis (Patlak, 1983) to assess changes in BBB Gd-DTPA permeability following middle cerebral artery occlusion with reperfusion in the rat. This method limits known problems with magnetic susceptibility mismatch and may thus allow greater accuracy in BBB permeability measurement in small animals.
Collapse
Affiliation(s)
- Jeffrey H Walton
- NMR Facility and Biomedical Engineering Graduate Group, University of California, Davis, USA.
| | - Kit Fai Ng
- Division of Cardiovascular Medicine, University of California, Davis, USA
| | - Steven E Anderson
- Department of Physiology and Membrane Biology, University of California, Davis, USA
| | - John C Rutledge
- Division of Cardiovascular Medicine, University of California, Davis, USA
| |
Collapse
|
11
|
Oakden W, Stanisz GJ. Effects of diffusion on high-resolution quantitative T2 MRI. NMR IN BIOMEDICINE 2014; 27:672-680. [PMID: 24700546 DOI: 10.1002/nbm.3104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/16/2014] [Accepted: 03/07/2014] [Indexed: 06/03/2023]
Abstract
Carr-Purcell-Meiboom-Gill-based sequences are often assumed to be insensitive to diffusion. However, imaging gradients always contribute some degree of diffusion weighting which increases with resolution. This may cause an apparent decrease in T2 when using a multi-echo sequence, such as quantitative T2 (qT2) at high resolution. This study investigated the impact of diffusion on the qT2 sequence. An equation was developed relating the diffusion factor associated with each echo (bqT2 ) to the underestimation of T2 , which was strongly dependent on both the actual T2 and the apparent diffusion coefficient of the tissue. The diffusion dependence of the measured T2 was demonstrated in rat spinal cord. The measured T2 was independent of the imaging plane in gray matter, where diffusion was isotropic, and orientation dependent in white matter, where diffusion was strongly anisotropic. The dependence of the measured T2 on the actual T2 value was also demonstrated in MnCl2 phantoms. The relationship between the resolution and underestimation of T2 was investigated both theoretically and experimentally for the original readout and a fully refocused readout. The fully refocused readout increased the resolution at which diffusion effects could be neglected whilst measuring T2 . To avoid the misidentification of cerebrospinal fluid when applying qT2 in the brain or spinal cord, a minimum in-plane voxel dimension of 0.2 mm was suggested for the standard qT2 sequence and 0.1 mm for the refocused readout. Simulations of myelin water fraction measurement indicated that signal-to-noise ratio requirements were increased in the presence of diffusion. Finally, the use of decreasing spoiler gradients to attenuate stimulated echoes should be avoided, as it was found to distort the T2 distribution when the slice thickness was less than 1 mm.
Collapse
Affiliation(s)
- Wendy Oakden
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | | |
Collapse
|