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Shin SH, Moazamian D, Suprana A, Zeng C, Athertya JS, Carl M, Ma Y, Jang H, Du J. Yet more evidence that non-aqueous myelin lipids can be directly imaged with ultrashort echo time (UTE) MRI on a clinical 3T scanner: a lyophilized red blood cell membrane lipid study. Neuroimage 2024; 296:120666. [PMID: 38830440 DOI: 10.1016/j.neuroimage.2024.120666] [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: 08/21/2023] [Revised: 05/16/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024] Open
Abstract
Direct imaging of semi-solid lipids, such as myelin, is of great interest as a noninvasive biomarker of neurodegenerative diseases. Yet, the short T2 relaxation times of semi-solid lipid protons hamper direct detection through conventional magnetic resonance imaging (MRI) pulse sequences. In this study, we examined whether a three-dimensional ultrashort echo time (3D UTE) sequence can directly acquire signals from membrane lipids. Membrane lipids from red blood cells (RBC) were collected from commercially available blood as a general model of the myelin lipid bilayer and subjected to D2O exchange and freeze-drying for complete water removal. Sufficiently high MR signals were detected with the 3D UTE sequence, which showed an ultrashort T2* of ∼77-271 µs and a short T1 of ∼189 ms for semi-solid RBC membrane lipids. These measurements can guide designing UTE-based sequences for direct in vivo imaging of membrane lipids.
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Affiliation(s)
- Soo Hyun Shin
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Dina Moazamian
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Arya Suprana
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Shu Chien-Gene Lay Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Chun Zeng
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Jiyo S Athertya
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | | | - Yajun Ma
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Shu Chien-Gene Lay Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, La Jolla, CA, USA.
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2
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Deveshwar N, Yao J, Han M, Dwork N, Shen X, Ljungberg E, Caverzasi E, Cao P, Henry R, Green A, Larson PEZ. Quantification of the in vivo brain ultrashort-T 2* component in healthy volunteers. Magn Reson Med 2024; 91:2417-2430. [PMID: 38291598 DOI: 10.1002/mrm.30013] [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: 04/28/2023] [Revised: 12/14/2023] [Accepted: 12/29/2023] [Indexed: 02/01/2024]
Abstract
PURPOSE Recent work has shown MRI is able to measure and quantify signals of phospholipid membrane-bound protons associated with myelin in the human brain. This work seeks to develop an improved technique for characterizing this brain ultrashort-T 2 ∗ $$ {\mathrm{T}}_2\ast $$ component in vivo accounting forT 1 $$ {\mathrm{T}}_1 $$ weighting. METHODS Data from ultrashort echo time scans from 16 healthy volunteers with variable flip angles (VFA) were collected and fitted into an advanced regression model to quantify signal fraction, relaxation time, and frequency shift of the ultrashort-T 2 ∗ $$ {\mathrm{T}}_2\ast $$ component. RESULTS The fitted components show intra-subject differences of different white matter structures and significantly elevated ultrashort-T 2 ∗ $$ {\mathrm{T}}_2\ast $$ signal fraction in the corticospinal tracts measured at 0.09 versus 0.06 in other white matter structures and significantly elevated ultrashort-T 2 ∗ $$ {\mathrm{T}}_2\ast $$ frequency shift in the body of the corpus callosum at- $$ - $$ 1.5 versus- $$ - $$ 2.0 ppm in other white matter structures. CONCLUSION The significantly different measured components and measuredT 1 $$ {\mathrm{T}}_1 $$ relaxation time of the ultrashort-T 2 ∗ $$ {\mathrm{T}}_2\ast $$ component suggest that this method is picking up novel signals from phospholipid membrane-bound protons.
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Affiliation(s)
- Nikhil Deveshwar
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- UC Berkeley - UCSF Graduate Program in Bioengineering, San Francisco, California, USA
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, California, USA
| | - Jingwen Yao
- UC Berkeley - UCSF Graduate Program in Bioengineering, San Francisco, California, USA
| | - Misung Han
- UC Berkeley - UCSF Graduate Program in Bioengineering, San Francisco, California, USA
| | - Nicholas Dwork
- Departments of Biomedical Informatics and Radiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Xin Shen
- UC Berkeley - UCSF Graduate Program in Bioengineering, San Francisco, California, USA
| | - Emil Ljungberg
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Eduardo Caverzasi
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Peng Cao
- Department of Diagnostic Radiology, Hong Kong University, Hong Kong, China
| | - Roland Henry
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
| | - Ari Green
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- UC Berkeley - UCSF Graduate Program in Bioengineering, San Francisco, California, USA
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Searleman AC, Ma Y, Sampath S, Sampath S, Bussell R, Chang EY, Deaton L, Schumacher AM, Du J. 3D inversion recovery ultrashort echo time MRI can detect demyelination in cuprizone-treated mice. FRONTIERS IN NEUROIMAGING 2024; 3:1356713. [PMID: 38783990 PMCID: PMC11111995 DOI: 10.3389/fnimg.2024.1356713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 04/15/2024] [Indexed: 05/25/2024]
Abstract
Purpose To test the ability of inversion-recovery ultrashort echo time (IR-UTE) MRI to directly detect demyelination in mice using a standard cuprizone mouse model. Methods Non-aqueous myelin protons have ultrashort T2s and are "invisible" with conventional MRI sequences but can be detected with UTE sequences. The IR-UTE sequence uses an adiabatic inversion-recovery preparation to suppress the long T2 water signal so that the remaining signal is from the ultrashort T2 myelin component. In this study, eight 8-week-old C57BL/6 mice were fed cuprizone (n = 4) or control chow (n = 4) for 5 weeks and then imaged by 3D IR-UTE MRI. The differences in IR-UTE signal were compared in the major white matter tracts in the brain and correlated with the Luxol Fast Blue histochemical marker of myelin. Results IR-UTE signal decreased in cuprizone-treated mice in white matter known to be sensitive to demyelination in this model, such as the corpus callosum, but not in white matter known to be resistant to demyelination, such as the internal capsule. These findings correlated with histochemical staining of myelin content. Conclusions 3D IR-UTE MRI was sensitive to cuprizone-induced demyelination in the mouse brain, and is a promising noninvasive method for measuring brain myelin content.
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Affiliation(s)
- Adam C. Searleman
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Srihari Sampath
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Srinath Sampath
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Robert Bussell
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Eric Y. Chang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
| | - Lisa Deaton
- Novartis Institutes for BioMedical Research, San Diego, CA, United States
| | | | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
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4
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Cho H, Han S, Cho HJ. Empirical relationship between TEM-derived myelin volume fraction and MRI-R 2 values in aging ex vivo rat corpus callosum. Magn Reson Imaging 2023; 103:75-83. [PMID: 37451521 DOI: 10.1016/j.mri.2023.07.006] [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: 03/16/2023] [Revised: 05/26/2023] [Accepted: 07/09/2023] [Indexed: 07/18/2023]
Abstract
Ex vivo ratiometric measurements of short- and long-T2 components using the multiple spin echo sequence of MRI are often employed to evaluate alterations in myelin content in the white matter (WM) of the brain. However, the relationship between absolute MRI-T2 values (long-T2 component) and myelin volumetric information in aged ex vivo rodent WM appears to be influenced by factors such as animal species, field strength, and fixation durations/washing. Here, multiple spin echo sequence-based MRI-R2 (the reciprocal of T2) values were measured in the corpus callosum (CC) region in the post-mortem rat brains (n = 9) of different age groups with common fixation techniques without washing at 7 T. Transmission electron microscopy (TEM)-based quantification of myelin volume fraction (MVF) and corresponding Monte-Carlo simulation to estimate relaxation rates (R2,IE) due to diffusion in the presence of inhomogeneous magnetic field perturbation in intra- and extra-cellular (IE) spaces were respectively performed. To determine whether the short-T2 components originating from myelin water were mixed with long-T2 components from IE water or were undetectable, the MVF values obtained from TEM results were respectively compared with MRI-R2 and R2,IE values. A significant correlation (Pearson's correlation coefficient r = 0.8763; p < 0.01) of average MRI-R2 and MVF values was observed. Estimated R2,IE values from Monte-Carlo simulations in IE water signals were also positively correlated (r = 0.8281; p < 0.01) with MVF values. However, the magnitudes of R2,IE values were much smaller than those observed for MRI-R2 values, indicating that changes in R2 related MVF are likely dominated by myelin water components. Such comparisons between independent parameters from MRI, TEM, and simulations support the suggestion that myelin water signals were indistinguishably mixed to exhibit mono-exponential T2 relaxation, and multiple spin echo sequence-based MRI-R2 values in aging ex vivo rat CC without prolonged washing still reflect the volumetric information of myelin, likely due to enhanced water exchange across the myelin.
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Affiliation(s)
- Hwapyeong Cho
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Sohyun Han
- Research Equipment Operations Division, Korea Basic Science Institute, Cheongju, South Korea.
| | - Hyung Joon Cho
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea.
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5
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Baadsvik EL, Weiger M, Froidevaux R, Faigle W, Ineichen BV, Pruessmann KP. Quantitative magnetic resonance mapping of the myelin bilayer reflects pathology in multiple sclerosis brain tissue. SCIENCE ADVANCES 2023; 9:eadi0611. [PMID: 37566661 PMCID: PMC10421026 DOI: 10.1126/sciadv.adi0611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/07/2023] [Indexed: 08/13/2023]
Abstract
Multiple sclerosis (MS) is a neuroinflammatory disease characterized by loss of myelin (demyelination) and, to a certain extent, subsequent myelin repair (remyelination). To better understand the pathomechanisms underlying de- and remyelination and to monitor the efficacy of treatments aimed at regenerating myelin, techniques offering noninvasive visualizations of myelin are warranted. Magnetic resonance (MR) imaging has long been at the forefront of efforts to visualize myelin, but it has only recently become feasible to access the rapidly decaying resonance signals stemming from the myelin lipid-protein bilayer itself. Here, we show that direct MR mapping of the bilayer yields highly specific myelin maps in brain tissue from patients with MS. Furthermore, examination of the bilayer signal behavior is found to reveal pathological alterations in normal-appearing white and gray matter. These results indicate promise for in vivo implementations of the myelin bilayer mapping technique, with prospective applications in basic research, diagnostics, disease monitoring, and drug development.
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Affiliation(s)
- Emily Louise Baadsvik
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Wolfgang Faigle
- Neuroimmunology and MS Research Section, Neurology Clinic, University of Zurich, University Hospital Zurich, Zurich, Switzerland
- Institut Curie, Immunity and Cancer Unit 932, Paris, France
| | - Benjamin V. Ineichen
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Center for Reproducible Science, University of Zurich, Zurich, Switzerland
| | - Klaas P. Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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6
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Endt S, Engel M, Naldi E, Assereto R, Molendowska M, Mueller L, Mayrink Verdun C, Pirkl CM, Palombo M, Jones DK, Menzel MI. In Vivo Myelin Water Quantification Using Diffusion-Relaxation Correlation MRI: A Comparison of 1D and 2D Methods. APPLIED MAGNETIC RESONANCE 2023; 54:1571-1588. [PMID: 38037641 PMCID: PMC10682074 DOI: 10.1007/s00723-023-01584-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/18/2023] [Accepted: 07/25/2023] [Indexed: 12/02/2023]
Abstract
Multidimensional Magnetic Resonance Imaging (MRI) is a versatile tool for microstructure mapping. We use a diffusion weighted inversion recovery spin echo (DW-IR-SE) sequence with spiral readouts at ultra-strong gradients to acquire a rich diffusion-relaxation data set with sensitivity to myelin water. We reconstruct 1D and 2D spectra with a two-step convex optimization approach and investigate a variety of multidimensional MRI methods, including 1D multi-component relaxometry, 1D multi-component diffusometry, 2D relaxation correlation imaging, and 2D diffusion-relaxation correlation spectroscopic imaging (DR-CSI), in terms of their potential to quantify tissue microstructure, including the myelin water fraction (MWF). We observe a distinct spectral peak that we attribute to myelin water in multi-component T1 relaxometry, T1-T2 correlation, T1-D correlation, and T2-D correlation imaging. Due to lower achievable echo times compared to diffusometry, MWF maps from relaxometry have higher quality. Whilst 1D multi-component T1 data allows much faster myelin mapping, 2D approaches could offer unique insights into tissue microstructure and especially myelin diffusion.
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Affiliation(s)
- Sebastian Endt
- Technical University of Munich, Munich, Germany
- AImotion Bavaria, Technische Hochschule Ingolstadt, Ingolstadt, Germany
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
| | - Maria Engel
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
| | - Emanuele Naldi
- Technische Universität Braunschweig, Braunschweig, Germany
| | | | - Malwina Molendowska
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
- Medical Radiation Physics, Lund University, Lund, Sweden
| | - Lars Mueller
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
- Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - Claudio Mayrink Verdun
- Technical University of Munich, Munich, Germany
- Munich Center for Machine Learning, Munich, Germany
| | | | - Marco Palombo
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
| | - Derek K. Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
| | - Marion I. Menzel
- Technical University of Munich, Munich, Germany
- AImotion Bavaria, Technische Hochschule Ingolstadt, Ingolstadt, Germany
- GE HealthCare, Munich, Germany
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7
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Reynolds LA, Morris SR, Vavasour IM, Barlow L, Laule C, MacKay AL, Michal CA. Nonaqueous magnetization following adiabatic and selective pulses in brain: T1 and cross-relaxation dynamics. NMR IN BIOMEDICINE 2023:e4936. [PMID: 36973767 DOI: 10.1002/nbm.4936] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/03/2023] [Accepted: 03/20/2023] [Indexed: 06/18/2023]
Abstract
Inversion pulses are commonly employed in MRI for T 1 $$ {T}_1 $$ -weighted contrast and relaxation measurements. In the brain, it is often assumed that adiabatic pulses saturate the nonaqueous magnetization. We investigated this assumption using solid-state NMR to monitor the nonaqueous signal directly following adiabatic inversion and compared this with signals following hard and soft inversion pulses. The effects of the different preparations on relaxation dynamics were explored. Inversion recovery experiments were performed on ex vivo bovine and porcine brains using 360-MHz (8.4 T) and 200-MHz (4.7 T) NMR spectrometers, respectively, using broadband rectangular, adiabatic, and sinc inversion pulses as well as a long rectangular saturation pulse. Analogous human brain MRI experiments were performed at 3 T using single-slice echo-planar imaging. Relaxation data were fitted by mono- and biexponential decay models. Further fitting analysis was performed using only two inversion delay times. Adiabatic and sinc inversion left much of the nonaqueous magnetization along B 0 $$ {B}_0 $$ and resulted in biexponential relaxation. Saturation of both aqueous and nonaqueous magnetization components led to effectively monoexponential T 1 $$ {T}_1 $$ relaxation. Typical adiabatic inversion pulses do not, as has been widely assumed, saturate the nonaqueous proton magnetization in white matter. Unequal magnetization states in aqueous and nonaqueous 1 H reservoirs prepared by soft and adiabatic pulses result in biexponential T 1 $$ {T}_1 $$ relaxation. Both pools must be prepared in the same magnetization state (e.g., saturated or inverted) in order to observe consistent monoexponential relaxation.
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Affiliation(s)
- Luke A Reynolds
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Sarah R Morris
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, Blusson Spinal Cord Centre, University of British Columbia, Vancouver, BC, Canada
| | - Irene M Vavasour
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, Blusson Spinal Cord Centre, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Laura Barlow
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Cornelia Laule
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, Blusson Spinal Cord Centre, University of British Columbia, Vancouver, BC, Canada
- Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Alex L MacKay
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Carl A Michal
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
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Chen Z, Huang J, Lai JHC, Tse KH, Xu J, Chan KWY. Chemical exchange saturation transfer MRI detects myelin changes in cuprizone mouse model at 3T. NMR IN BIOMEDICINE 2023:e4937. [PMID: 36965064 DOI: 10.1002/nbm.4937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 02/18/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
Chemical exchange saturation transfer (CEST) sensitively detects molecular alterations in the brain, such as relayed nuclear Overhauser effect (rNOE) CEST contrast at -3.5 ppm representing aliphatic protons in both lipids and proteins, and CEST contrast at 3.5 ppm correlating with amide proton in proteins. Myelin is rich in lipids and proteins, and therefore CEST can be explored as a biomarker for myelin pathology, which could contribute to the diagnosis and prognosis of multiple sclerosis (MS). In the current study, we investigate the specificity of aliphatic rNOE and the amide pool in myelin detection using the cuprizone (CPZ) mouse model, which recapitulates the demyelination and remyelination of MS. In this study, preclinical 3T MRI was performed in 19 male C57BL/6 mice. Mice in the normal control (NC) group (n = 9) were fed a normal diet for the whole course, while mice in the CPZ group (n = 10) were fed with CPZ for 10 weeks, followed by 4 weeks with a normal diet. The CEST contrast of rNOE (-3.5 ppm) and amide (3.5 ppm) in brain regions of the corpus callosum (CC) and the caudate putamen were compared. Statistical differences between the groups were calculated using two-way ANOVA. We observed significantly decreased rNOE (NC: 4.85% ± 0.09%/s vs. CPZ: 3.88% ± 0.18%/s, p = 0.007) and amide pool (NC: 3.20% ± 0.10%/s vs. CPZ: 2.46% ± 0.16%/s, p = 0.02) in the CC after 8 weeks on CPZ diet (p < 0.05). Moreover, the rNOE in the CPZ group recovered to a level comparable with the NC group at week 14 (p = 0.39), while amide remained at a level as low as that for the NC group (p = 0.051). Significant rNOE and amide changes, validated by immunohistochemistry results for demyelination and remyelination, demonstrate the huge potential of CEST for revealing myelin pathology, which has implications for MS identification at the clinical field strength of 3T.
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Affiliation(s)
- Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jianpan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Joseph H C Lai
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Kai-Hei Tse
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kannie W Y Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- Tung Biomedical Science Centre, City University of Hong Kong, Hong Kong, China
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9
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Sedaghat S, Jang H, Athertya JS, Groezinger M, Corey-Bloom J, Du J. The signal intensity variation of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) as a potential biomarker for patients' disability: A feasibility study. Front Neurosci 2023; 17:1145251. [PMID: 36992852 PMCID: PMC10040653 DOI: 10.3389/fnins.2023.1145251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
Introduction Although many lesion-based MRI biomarkers in multiple sclerosis (MS) patients were investigated, none of the previous studies dealt with the signal intensity variations (SIVs) of MS lesions. In this study, the SIVs of MS lesions on direct myelin imaging and standard clinical sequences as possible MRI biomarkers for disability in MS patients were assessed. Methods Twenty seven MS patients were included in this prospective study. IR-UTE, FLAIR, and MPRAGE sequences were employed on a 3T scanner. Regions of interest (ROIs) were manually drawn within the MS lesions, and the cerebrospinal fluid (CSF) and signal intensity ratios (SIR) were calculated from the derived values. Variations coefficients were determined from the standard deviations (Coeff 1) and the absolute differences (Coeff 2) of the SIRs. Disability grade was assessed by the expanded disability status scale (EDSS). Cortical/gray matter, subcortical, infratentorial, and spinal lesions were excluded. Results The mean diameter of the lesions was 7.8 ± 1.97 mm, while the mean EDSS score was 4.5 ± 1.73. We found moderate correlations between the EDSS and Coeff 1 and 2 on IR-UTE and MPRAGE images. Accordingly, Pearson's correlations on IR-UTE were R = 0.51 (p = 0.007) and R = 0.49 (p = 0.01) for Coeff 1 and 2, respectively. For MPRAGE, Pearson's correlations were R = 0.5 (p = 0.008) and R = 0.48 (p = 0.012) for Coeff 1 and 2, respectively. For FLAIR, only poor correlations could be found. Conclusion The SIVs of MS lesions on IR-UTE and MPRAGE images, assessed by Coeff 1 and 2, could be used as novel potential MRI biomarkers for patients' disability.
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Affiliation(s)
- Sam Sedaghat
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- University Hospital Heidelberg, Heidelberg, Germany
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Jiyo S. Athertya
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | | | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
- Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
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10
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Baadsvik EL, Weiger M, Froidevaux R, Faigle W, Ineichen BV, Pruessmann KP. Mapping the myelin bilayer with short-T 2 MRI: Methods validation and reference data for healthy human brain. Magn Reson Med 2023; 89:665-677. [PMID: 36253953 PMCID: PMC10091754 DOI: 10.1002/mrm.29481] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/24/2022] [Accepted: 09/20/2022] [Indexed: 12/13/2022]
Abstract
PURPOSE To explore the properties of short-T2 signals in human brain, investigate the impact of various experimental procedures on these properties and evaluate the performance of three-component analysis. METHODS Eight samples of non-pathological human brain tissue were subjected to different combinations of experimental procedures including D2 O exchange and frozen storage. Short-T2 imaging techniques were employed to acquire multi-TE (33-2067 μs) data, to which a three-component complex model was fitted in two steps to recover the properties of the underlying signal components and produce amplitude maps of each component. For validation of the component amplitude maps, the samples underwent immunohistochemical myelin staining. RESULTS The signal component representing the myelin bilayer exhibited super-exponential decay with T2,min of 5.48 μs and a chemical shift of 1.07 ppm, and its amplitude could be successfully mapped in both white and gray matter in all samples. These myelin maps corresponded well to myelin-stained tissue sections. Gray matter signals exhibited somewhat different components than white matter signals, but both tissue types were well represented by the signal model. Frozen tissue storage did not alter the signal components but influenced component amplitudes. D2 O exchange was necessary to characterize the non-aqueous signal components, but component amplitude mapping could be reliably performed also in the presence of H2 O signals. CONCLUSIONS The myelin mapping approach explored here produced reasonable and stable results for all samples. The extensive tissue and methodological investigations performed in this work form a basis for signal interpretation in future studies both ex vivo and in vivo.
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Affiliation(s)
- Emily Louise Baadsvik
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Wolfgang Faigle
- Neuroimmunology and MS Research Section, Neurology Clinic, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Benjamin Victor Ineichen
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Klaas Paul Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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11
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Sukstanskii AL, Yablonskiy DA. Microscopic theory of spin-spin and spin-lattice relaxation of bound protons in cellular and myelin membranes-A lateral diffusion model (LDM). Magn Reson Med 2023; 89:370-383. [PMID: 36094730 PMCID: PMC9826187 DOI: 10.1002/mrm.29430] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/26/2022] [Accepted: 08/08/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE Deciphering salient features of biological tissue cellular microstructure in health and diseases is an ultimate goal of MRI. While most MRI approaches are based on studying MR properties of tissue "free" water indirectly affected by tissue microstructure, other approaches, such as magnetization transfer (MT), directly target signals from tissue-forming macromolecules. However, despite three-decades of successful applications, relationships between MT measurements and tissue microstructure remain elusive, hampering interpretation of experimental results. The goal of this paper is to develop microscopic theory connecting the structure of cellular and myelin membranes to their MR properties. THEORY AND METHODS Herein we introduce a lateral diffusion model (LDM) that explains the T2 (spin-spin) and T1 (spin-lattice) MRI relaxation properties of the macromolecular-bound protons by their dipole-dipole interaction modulated by the lateral diffusion of long lipid molecules forming cellular and myelin membranes. RESULTS LDM predicts anisotropic T1 and T2 relaxation of membrane-bound protons. Moreover, their T2 relaxation cannot be described in terms of a standard R2 = 1/T2 relaxation rate parameter, but rather by a relaxation rate function R2 (t) that depends on time t after RF excitation, having, in the main approximation, a logarithmic behavior: R2 (t) ∼ lnt. This anisotropic non-linear relaxation leads to an absorption lineshape that is different from Super-Lorentzian traditionally used in interpreting MT experiments. CONCLUSION LDM-derived analytical equations connect the membrane-bound protons T1 and T2 relaxation with dynamic distances between protons in neighboring membrane-forming lipid molecules and their lateral diffusion. This sheds new light on relationships between MT parameters and microstructure of cellular and myelin membranes.
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12
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Ma Y, Jang H, Jerban S, Chang EY, Chung CB, Bydder GM, Du J. Making the invisible visible-ultrashort echo time magnetic resonance imaging: Technical developments and applications. APPLIED PHYSICS REVIEWS 2022; 9:041303. [PMID: 36467869 PMCID: PMC9677812 DOI: 10.1063/5.0086459] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/12/2022] [Indexed: 05/25/2023]
Abstract
Magnetic resonance imaging (MRI) uses a large magnetic field and radio waves to generate images of tissues in the body. Conventional MRI techniques have been developed to image and quantify tissues and fluids with long transverse relaxation times (T2s), such as muscle, cartilage, liver, white matter, gray matter, spinal cord, and cerebrospinal fluid. However, the body also contains many tissues and tissue components such as the osteochondral junction, menisci, ligaments, tendons, bone, lung parenchyma, and myelin, which have short or ultrashort T2s. After radio frequency excitation, their transverse magnetizations typically decay to zero or near zero before the receiving mode is enabled for spatial encoding with conventional MR imaging. As a result, these tissues appear dark, and their MR properties are inaccessible. However, when ultrashort echo times (UTEs) are used, signals can be detected from these tissues before they decay to zero. This review summarizes recent technical developments in UTE MRI of tissues with short and ultrashort T2 relaxation times. A series of UTE MRI techniques for high-resolution morphological and quantitative imaging of these short-T2 tissues are discussed. Applications of UTE imaging in the musculoskeletal, nervous, respiratory, gastrointestinal, and cardiovascular systems of the body are included.
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Affiliation(s)
- Yajun Ma
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California 92037, USA
| | | | | | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Jiang Du
- Author to whom correspondence should be addressed:. Tel.: (858) 246-2248, Fax: (858) 246-2221
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13
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Shaghaghi M, Cai K. Toward In Vivo MRI of the Tissue Proton Exchange Rate in Humans. BIOSENSORS 2022; 12:bios12100815. [PMID: 36290953 PMCID: PMC9599426 DOI: 10.3390/bios12100815] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/19/2022] [Accepted: 09/29/2022] [Indexed: 05/28/2023]
Abstract
Quantification of proton exchange rate (kex) is a challenge in MR studies. Current techniques either have low resolutions or are dependent on the estimation of parameters that are not measurable. The Omega plot method, on the other hand, provides a direct way for determining kex independent of the agent concentration. However, it cannot be used for in vivo studies without some modification due to the contributions from the water signal. In vivo tissue proton exchange rate (kex) MRI, based on the direct saturation (DS) removed Omega plot, quantifies the weighted average of kex of the endogenous tissue metabolites. This technique has been successfully employed for imaging the variation in the kex of ex vivo phantoms, as well as in vivo human brains in healthy subjects, and stroke or multiple sclerosis (MS) patients. In this paper, we present a brief review of the methods used for kex imaging with a focus on the development of in vivo kex MRI technique based on the DS-removed Omega plot. We then review the recent clinical studies utilizing this technique for better characterizing brain lesions. We also outline technical challenges for the presented technique and discuss its prospects for detecting tissue microenvironmental changes under oxidative stress.
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Affiliation(s)
- Mehran Shaghaghi
- Department of Radiology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Kejia Cai
- Department of Radiology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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14
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Ullah MS, Mankinen O, Zhivonitko VV, Telkki VV. Ultrafast transverse relaxation exchange NMR spectroscopy. Phys Chem Chem Phys 2022; 24:22109-22114. [PMID: 36074123 PMCID: PMC9491048 DOI: 10.1039/d2cp02944h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular exchange between different physical or chemical environments occurs due to either diffusion or chemical transformation. Nuclear magnetic resonance (NMR) spectroscopy provides a means of understanding the molecular exchange in a noninvasive way and without tracers. Here, we introduce a novel two dimensional, single-scan ultrafast Laplace NMR (UF LNMR) method to monitor molecular exchange using transverse relaxation as a contrast. The UF T2–T2 relaxation exchange spectroscopy (REXSY) method shortens the experiment time by one to two orders of magnitude compared to its conventional counterpart. Contrary to the conventional EXSY, the exchanging sites are distinguished based on T2 relaxation times instead of chemical shifts, making the method especially useful for systems including physical exchange of molecules. Therefore, the UF REXSY method offers an efficient means for quantification of exchange processes in various fields such as cellular metabolism and ion transport in electrolytes. As a proof of principle, we studied a halogen-free orthoborate based ionic liquid system and followed molecular exchange between molecular aggregates and free molecules. The results are in good agreement with the conventional exchange studies. Due to the single-scan nature, the method potentially significantly facilitates the use of modern hyperpolarization techniques to boost the sensitivity by several orders of magnitude. An ultrafast two-dimensional NMR method allows quantification of molecular exchange rates efficiently based on T2 relaxation contrast.![]()
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Affiliation(s)
- Md Sharif Ullah
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Otto Mankinen
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Vladimir V Zhivonitko
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Ville-Veikko Telkki
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
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15
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Müller M, Egger N, Sommer S, Wilferth T, Meixner CR, Laun FB, Mennecke A, Schmidt M, Huhn K, Rothhammer V, Uder M, Dörfler A, Nagel AM. Direct imaging of white matter ultrashort T 2∗ components at 7 Tesla. Magn Reson Imaging 2021; 86:107-117. [PMID: 34906631 DOI: 10.1016/j.mri.2021.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/02/2021] [Accepted: 11/29/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE To demonstrate direct imaging of the white matter ultrashort T2∗ components at 7 Tesla using inversion recovery (IR)-enhanced ultrashort echo time (UTE) MRI. To investigate its characteristics, potentials and limitations, and to establish a clinical protocol. MATERIAL AND METHODS The IR UTE technique suppresses long T2∗ signals within white matter by using adiabatic inversion in combination with dual-echo difference imaging. Artifacts arising at 7 T from long T2∗ scalp fat components were reduced by frequency shifting the IR pulse such that those frequencies were inverted likewise. For 8 healthy volunteers, the T2∗ relaxation times of white matter were then quantified. In 20 healthy volunteers, the UTE difference and fraction contrast were evaluated. Finally, in 6 patients with multiple sclerosis (MS), the performance of the technique was assessed. RESULTS A frequency shift of -1.2 ppm of the IR pulse (i.e. towards the fat frequency) provided a good suppression of artifacts. With this, an ultrashort compartment of (68 ± 6) % with a T2∗ time of (147 ± 58) μs was quantified with a chemical shift of (-3.6 ± 0.5) ppm from water. Within healthy volunteers' white matter, a stable ultrashort T2∗ fraction contrast was calculated. For the MS patients, a significant fraction reduction in the identified lesions as well as in the normal-appearing white matter was observed. CONCLUSIONS The quantification results indicate that the observed ultrashort components arise primarily from myelin tissue. Direct IR UTE imaging of the white matter ultrashort T2∗ components is thus feasible at 7 T with high quantitative inter-subject repeatability and good detection of signal loss in MS.
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Affiliation(s)
- Max Müller
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Nico Egger
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Stefan Sommer
- Siemens Healthcare, Zurich, Switzerland; Swiss Center for Musculoskeletal Imaging (SCMI), Balgrist Campus, Zurich, Switzerland
| | - Tobias Wilferth
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Christian R Meixner
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Frederik Bernd Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Angelika Mennecke
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Manuel Schmidt
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Konstantin Huhn
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Veit Rothhammer
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Arnd Dörfler
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Armin M Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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16
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Gaeta M, Cavallaro M, Vinci SL, Mormina E, Blandino A, Marino MA, Granata F, Tessitore A, Galletta K, D'Angelo T, Visalli C. Magnetism of materials: theory and practice in magnetic resonance imaging. Insights Imaging 2021; 12:179. [PMID: 34862955 PMCID: PMC8643382 DOI: 10.1186/s13244-021-01125-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 11/08/2021] [Indexed: 02/03/2023] Open
Abstract
All substances exert magnetic properties in some extent when placed in an external magnetic field. Magnetic susceptibility represents a measure of the magnitude of magnetization of a certain substance when the external magnetic field is applied. Depending on the tendency to be repelled or attracted by the magnetic field and in the latter case on the magnitude of this effect, materials can be classified as diamagnetic or paramagnetic, superparamagnetic and ferromagnetic, respectively. Knowledge of type and extent of susceptibility of common endogenous and exogenous substances and how their magnetic properties affect the conventional sequences used in magnetic resonance imaging (MRI) can help recognize them and exalt or minimize their presence in the acquired images, so as to improve diagnosis in a wide variety of benign and malignant diseases. Furthermore, in the context of diamagnetic susceptibility, chemical shift imaging enables to assess the intra-voxel ratio between water and fat content, analyzing the tissue composition of various organs and allowing a precise fat quantification. The following article reviews the fundamental physical principles of magnetic susceptibility and examines the magnetic properties of the principal endogenous and exogenous substances of interest in MRI, providing potential through representative cases for improved diagnosis in daily clinical routine.
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Affiliation(s)
- Michele Gaeta
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Marco Cavallaro
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Sergio Lucio Vinci
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Enricomaria Mormina
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy.
| | - Alfredo Blandino
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Maria Adele Marino
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Francesca Granata
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Agostino Tessitore
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Karol Galletta
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Tommaso D'Angelo
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
| | - Carmela Visalli
- Department of Biomedical Sciences and Morphological and Functional Imaging, Policlinico Universitario G. Martino, University of Messina, Via Consolare Valeria 1, 98100, Messina, Italy
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17
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Huang J, Xu J, Lai JHC, Chen Z, Lee CY, Mak HKF, Chan KH, Chan KWY. Relayed nuclear Overhauser effect weighted (rNOEw) imaging identifies multiple sclerosis. NEUROIMAGE-CLINICAL 2021; 32:102867. [PMID: 34751151 PMCID: PMC8569719 DOI: 10.1016/j.nicl.2021.102867] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/12/2021] [Accepted: 10/25/2021] [Indexed: 10/25/2022]
Abstract
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system in which the immune system attacks the myelin and axons, consequently leading to demyelination and axonal injury. Magnetic resonance imaging (MRI) plays a pivotal role in the diagnosis of MS, and currently various types of MRI techniques have been used to detect the pathology of MS based on unique mechanisms. In this study, we applied the relayed nuclear Overhauser effect weighted (rNOEw) imaging to study human MS at clinical 3T. Three groups of subjects, including 20 normal control (NC) subjects, 14 neuromyelitis optica spectrum disorders (NMOSD) patients and 21 MS patients, were examined at a clinical 3T MRI scanner. Whole-brain rNOEw images of each subject were obtained by acquiring a control and a labeled image within four minutes. Significantly lower brain rNOEw contrast was detected in MS group compared to NC (P = 0.008) and NMOSD (P = 0.014) groups, while no significant difference was found between NC and NMOSD groups (P = 0.939). The lower rNOEw contrast of MS group compared to NC/NMOSD group was significant in white matter (P = 0.041/0.021), gray matter (P = 0.004/0.020) and brain parenchyma (P = 0.015/0.021). Moreover, MS lesions showed higher number and larger size but lower rNOEw contrast than NMOSD lesions (P = 0.002). Our proposed rNOEw imaging scheme has potential to serve as a new method for assisting MS diagnosis. Importantly, it may be used to identify MS from NMOSD.
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Affiliation(s)
- Jianpan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Joseph H C Lai
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Chi Yan Lee
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Henry K F Mak
- Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Koon Ho Chan
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Kannie W Y Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; City University of Hong Kong Shenzhen Research Institute, Shenzhen, China; Hong Kong Centre for Cerebro-Cardiovascular Health Engineering, Hong Kong, China.
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18
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Jang H, Ma YJ, Chang EY, Fazeli S, Lee RR, Lombardi AF, Bydder GM, Corey-Bloom J, Du J. Inversion Recovery Ultrashort TE MR Imaging of Myelin is Significantly Correlated with Disability in Patients with Multiple Sclerosis. AJNR Am J Neuroradiol 2021; 42:868-874. [PMID: 33602747 DOI: 10.3174/ajnr.a7006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 11/16/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND PURPOSE MR imaging has been widely used for the noninvasive evaluation of MS. Although clinical MR imaging sequences are highly effective in showing focal macroscopic tissue abnormalities in the brains of patients with MS, they are not specific to myelin and correlate poorly with disability. We investigated direct imaging of myelin using a 2D adiabatic inversion recovery ultrashort TE sequence to determine its value in assessing disability in MS. MATERIALS AND METHODS The 2D inversion recovery ultrashort TE sequence was evaluated in 14 healthy volunteers and 31 patients with MS. MPRAGE and T2-FLAIR images were acquired for comparison. Advanced Normalization Tools were used to correlate inversion recovery ultrashort TE, MPRAGE, and T2-FLAIR images with disability assessed by the Expanded Disability Status Scale. RESULTS Weak correlations were observed between normal-appearing white matter volume (R = -0.03, P = .88), lesion load (R = 0.22, P = .24), and age (R = 0.14, P = .44), and disability. The MPRAGE signal in normal-appearing white matter showed a weak correlation with age (R = -0.10, P = .49) and disability (R = -0.19, P = .31). The T2-FLAIR signal in normal-appearing white matter showed a weak correlation with age (R = 0.01, P = .93) and disability (R = 0.13, P = .49). The inversion recovery ultrashort TE signal was significantly negatively correlated with age (R = -0.38, P = .009) and disability (R = -0.44; P = .01). CONCLUSIONS Direct imaging of myelin correlates with disability in patients with MS better than indirect imaging of long-T2 water in WM using conventional clinical sequences.
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Affiliation(s)
- H Jang
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
| | - Y-J Ma
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
| | - E Y Chang
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
- Radiology Service (E.Y.C., R.R.L.), VA San Diego Healthcare System, San Diego, California
| | - S Fazeli
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
| | - R R Lee
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
- Radiology Service (E.Y.C., R.R.L.), VA San Diego Healthcare System, San Diego, California
| | - A F Lombardi
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
| | - G M Bydder
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
| | - J Corey-Bloom
- Department of Neurosciences (J.C.-B.), University of California San Diego, San Diego, California
| | - J Du
- From the Department of Radiology (H.J., Y.-J.M., E.Y.C., S.F., R.R.L., A.F.L., G.M.B., J.D.), University of California San Diego, San Diego, California
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19
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Ljungberg E, Damestani NL, Wood TC, Lythgoe DJ, Zelaya F, Williams SCR, Solana AB, Barker GJ, Wiesinger F. Silent zero TE MR neuroimaging: Current state-of-the-art and future directions. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 123:73-93. [PMID: 34078538 DOI: 10.1016/j.pnmrs.2021.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Magnetic Resonance Imaging (MRI) scanners produce loud acoustic noise originating from vibrational Lorentz forces induced by rapidly changing currents in the magnetic field gradient coils. Using zero echo time (ZTE) MRI pulse sequences, gradient switching can be reduced to a minimum, which enables near silent operation.Besides silent MRI, ZTE offers further interesting characteristics, including a nominal echo time of TE = 0 (thus capturing short-lived signals from MR tissues which are otherwise MR-invisible), 3D radial sampling (providing motion robustness), and ultra-short repetition times (providing fast and efficient scanning).In this work we describe the main concepts behind ZTE imaging with a focus on conceptual understanding of the imaging sequences, relevant acquisition parameters, commonly observed image artefacts, and image contrasts. We will further describe a range of methods for anatomical and functional neuroimaging, together with recommendations for successful implementation.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
| | - Nikou L Damestani
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - David J Lythgoe
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Fernando Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | | | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom; ASL Europe, GE Healthcare, Munich, Germany
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20
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Ma YJ, Jang H, Wei Z, Wu M, Chang EY, Corey-Bloom J, Bydder GM, Du J. Brain ultrashort T 2 component imaging using a short TR adiabatic inversion recovery prepared dual-echo ultrashort TE sequence with complex echo subtraction (STAIR-dUTE-ES). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 323:106898. [PMID: 33429170 PMCID: PMC7855631 DOI: 10.1016/j.jmr.2020.106898] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/13/2020] [Accepted: 12/21/2020] [Indexed: 05/15/2023]
Abstract
Long T2 water contamination is a major challenge with direct in vivo UTE imaging of ultrashort T2 components in the brain since water contributes most of the signal detected from white and gray matter. The Short TR Adiabatic Inversion Recovery prepared Ultrashort TE (STAIR-UTE) sequence can significantly suppress water signals and simultaneously image ultrashort T2 components. However, the TR used may not be sufficiently short to allow the STAIR preparation to completely suppress all the water signals in the brain due to specific absorption rate (SAR) limitations on clinical MR scanners. In this study, we describe a STAIR prepared dual-echo UTE sequence with complex Echo Subtraction (STAIR-dUTE-ES) which improves water suppression for selective ultrashort T2 imaging compared with that achieved with the STAIR-UTE sequence. Numerical simulations showed that the STAIR-dUTE-ES technique can effectively suppress water signals and allow accurate quantification of ultrashort T2 protons. Volunteer and Multiple Sclerosis (MS) patient studies demonstrated the feasibility of the STAIR-dUTE-ES technique for selective imaging and quantification of ultrashort T2 components in vivo. A significantly lower mean UltraShort T2 Proton Fraction (USPF) was found in lesions in MS patients (5.7 ± 0.7%) compared with that in normal white matter of healthy volunteers (8.9 ± 0.6%). The STAIR-dUTE-ES sequence provides robust water suppression for volumetric imaging and quantitation of ultrashort T2 component. The reduced USPF in MS lesions shows the clinical potential of the sequence for diagnosis and monitoring treatment in MS.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California San Diego, San Diego, CA, USA.
| | - Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Zhao Wei
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Mei Wu
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California San Diego, San Diego, CA, USA; Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Graeme M Bydder
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, CA, USA.
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21
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Manning AP, MacKay AL, Michal CA. Understanding aqueous and non-aqueous proton T 1 relaxation in brain. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 323:106909. [PMID: 33453678 DOI: 10.1016/j.jmr.2020.106909] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 11/17/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
A full picture of longitudinal relaxation in complex heterogeneous environments like white matter brain tissue remains elusive. In tissue, successive approximations, from the solvation layer model to the two pool model, have highlighted how longitudinal magnetization evolution depends on both inter-compartmental exchange and spin-lattice relaxation. In white matter, however, these models fail to capture the behaviour of the two distinct aqueous pools, myelin water and intra/extra-cellular water. A challenge with testing more comprehensive multi-pool models lies in directly observing all pools, both aqueous and non-aqueous. In this work, we advance these efforts by integrating three main experimental and analytical elements: direct observation of the longitudinal relaxation of both the aqueous and the non-aqueous protons in white matter, a wide range of different initial conditions, and application of an analysis pipeline which includes lineshape, CPMG, and fitting of a four pool model. An eigenvector interpretation of the four pool model highlights how longitudinal relaxation in white matter depends on initial conditions. We find that a single set of model parameters is able to describe the entire range of relaxation behaviour observed in all the separable aqueous and non-aqueous pools in experiments involving six different initial conditions. Understanding of the nature and connectedness of the tissue components is crucial in the design and interpretation of many MRI measurements, especially those based on magnetization transfer and longitudinal relaxation. In particular, the dependency of relaxation behaviour on initial conditions is likely the basis for understanding method-dependent discrepancies in in vivo T1.
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Affiliation(s)
- Alan P Manning
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Alex L MacKay
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada; Department of Radiology, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada
| | - Carl A Michal
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada.
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22
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Ma YJ, Searleman AC, Jang H, Fan SJ, Wong J, Xue Y, Cai Z, Chang EY, Corey-Bloom J, Du J. Volumetric imaging of myelin in vivo using 3D inversion recovery-prepared ultrashort echo time cones magnetic resonance imaging. NMR IN BIOMEDICINE 2020; 33:e4326. [PMID: 32691472 PMCID: PMC7952008 DOI: 10.1002/nbm.4326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/19/2020] [Accepted: 05/02/2020] [Indexed: 05/28/2023]
Abstract
Direct myelin imaging is promising for characterization of multiple sclerosis (MS) brains at diagnosis and in response to therapy. In this study, a 3D inversion recovery-prepared ultrashort echo time cones (IR-UTE-Cones) sequence was used for both morphological and quantitative imaging of myelin on a clinical 3 T scanner. Myelin powder phantoms with different myelin concentrations were imaged with the 3D UTE-Cones sequence and it showed a strong correlation between concentrations and UTE-Cones signals, demonstrating the ability of the UTE-Cones sequence to directly image myelin in the brain. Quantitative myelin imaging with multi-echo IR-UTE-Cones sequences show similar T2 * values for a D2 O-exchanged myelin phantom (T2 * = 0.33 ± 0.04 ms), ex vivo brain specimens (T2 * = 0.20 ± 0.04 ms) and in vivo healthy volunteers (T2 * = 0.254 ± 0.023 ms), further confirming the feasibility of 3D IR-UTE-Cones sequences for direct myelin imaging in vivo. In ex vivo MS brain study, signal loss is observed in MS lesions, which was confirmed with histology. For the in vivo study, the lesions in MS patients also show myelin signal loss using the proposed direct myelin imaging method, demonstrating the clinical potential for MS diagnosis. Furthermore, the measured IR-UTE-Cones signal intensities show a significant difference between normal-appearing white matter in MS patients and normal white matter in volunteers, which cannot be found in clinical used T2 -FLAIR sequences. Thus, the proposed 3D IR-UTE-Cones sequence showed clinical potential for MS diagnosis with the capability of direct myelin detection of the whole brain.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Adam C. Searleman
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Shu-Juan Fan
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Jonathan Wong
- Department of Radiology, University of California San Diego, San Diego, CA, USA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Yanping Xue
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Zhenyu Cai
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Eric Y. Chang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, CA, USA
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23
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Zu Z, Lin EC, Louie EA, Xu J, Li H, Xie J, Lankford CL, Chekmenev EY, Swanson SD, Does MD, Gore JC, Gochberg DF. Relayed nuclear Overhauser enhancement sensitivity to membrane Cho phospholipids. Magn Reson Med 2020; 84:1961-1976. [PMID: 32243662 PMCID: PMC8238412 DOI: 10.1002/mrm.28258] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/17/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE Phospholipids are key constituents of cell membranes and serve vital functions in the regulation of cellular processes; thus, a method for in vivo detection and characterization could be valuable for detecting changes in cell membranes that are consequences of either normal or pathological processes. Here, we describe a new method to map the distribution of partially restricted phospholipids in tissues. METHODS The phospholipids were measured by signal changes caused by relayed nuclear Overhauser enhancement-mediated CEST between the phospholipid Cho headgroup methyl protons and water at around -1.6 ppm from the water resonance. The biophysical basis of this effect was examined by controlled manipulation of head group, chain length, temperature, degree of saturation, and presence of cholesterol. Additional experiments were performed on animal tumor models to evaluate potential applications of this novel signal while correcting for confounding contributions. RESULTS Negative relayed nuclear Overhauser dips in Z-spectra were measured from reconstituted Cho phospholipids with cholesterol but not for other Cho-containing metabolites or proteins. Significant contrast was found between tumor and contralateral normal tissue signals in animals when comparing both the measured saturation transfer signal and a more specific imaging metric. CONCLUSION We demonstrated specific relayed nuclear Overhauser effects in partially restricted phospholipid phantoms and similar effects in solid brain tumors after correcting for confounding signal contributions, suggesting possible translational applications of this novel molecular imaging method, which we name restricted phospholipid transfer.
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Affiliation(s)
- Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eugene C. Lin
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Elizabeth A. Louie
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee
| | - Jingping Xie
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
| | - Christopher L. Lankford
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
| | - Eduard Y. Chekmenev
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Scott D. Swanson
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Mark D. Does
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
- Department of Electrical Engineering, Vanderbilt University, Nashville, Tennessee
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Daniel F. Gochberg
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee
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24
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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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25
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Ma YJ, Jang H, Wei Z, Cai Z, Xue Y, Lee RR, Chang EY, Bydder GM, Corey-Bloom J, Du J. Myelin Imaging in Human Brain Using a Short Repetition Time Adiabatic Inversion Recovery Prepared Ultrashort Echo Time (STAIR-UTE) MRI Sequence in Multiple Sclerosis. Radiology 2020; 297:392-404. [PMID: 32779970 DOI: 10.1148/radiol.2020200425] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Water signal contamination is a major challenge for direct ultrashort echo time (UTE) imaging of myelin in vivo because water contributes most of the signals detected in white matter. Purpose To validate a new short repetition time (TR) adiabatic inversion recovery (STAIR) prepared UTE (STAIR-UTE) sequence designed to suppress water signals and to allow imaging of ultrashort T2 protons of myelin in white matter using a clinical 3-T scanner. Materials and Methods In this prospective study, an optimization framework was used to obtain the optimal inversion time for nulling water signals using STAIR-UTE imaging at different TRs. Numeric simulation and phantom studies were performed. Healthy volunteers and participants with multiple sclerosis (MS) underwent MRI between November 2018 and October 2019 to compare STAIR-UTE and a clinical T2-weighted fluid-attenuated inversion recovery sequence for assessment of MS lesions. UTE measures of myelin were also performed to allow comparison of signals in lesions and with those in normal-appearing white matter (NAWM) in patients with MS and in normal white matter (NWM) in healthy volunteers. Results Simulation and phantom studies both suggest that the proposed STAIR-UTE technique can effectively suppress long T2 tissues with a broad range of T1s. Ten healthy volunteers (mean age, 33 years ± 8 [standard deviation]; six women) and 10 patients with MS (mean age, 51 years ± 16; seven women) were evaluated. The three-dimensional STAIR-UTE sequence effectively suppressed water components in white matter and selectively imaged myelin, which had a measured T2* value of 0.21 msec ± 0.04 in the volunteer study. A much lower mean UTE measure of myelin proton density was found in MS lesions (3.8 mol/L ± 1.5), and a slightly lower mean UTE measure was found in NAWM (7.2 mol/L ± 0.8) compared with that in NWM (8.0 mol/L ± 0.8) in the healthy volunteers (P < .001 for both comparisons). Conclusion The short repetition time adiabatic inversion recovery-prepared ultrashort echo time sequence provided efficient water signal suppression for volumetric imaging of myelin in the brain and showed excellent myelin signal contrast as well as marked ultrashort echo time signal reduction in multiple sclerosis lesions and a smaller reduction in normal-appearing white matter compared with normal white matter in volunteers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Messina and Port in this issue.
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Affiliation(s)
- Ya-Jun Ma
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Hyungseok Jang
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Zhao Wei
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Zhenyu Cai
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Yanping Xue
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Roland R Lee
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Eric Y Chang
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Graeme M Bydder
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Jody Corey-Bloom
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
| | - Jiang Du
- From the Departments of Radiology (Y.J.M., H.J., Z.W., Z.C., Y.X., R.R.L., E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.B.) University of California San Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, Calif (E.Y.C.)
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26
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Ma YJ, Jang H, Chang EY, Hiniker A, Head BP, Lee RR, Corey-Bloom J, Bydder GM, Du J. Ultrashort echo time (UTE) magnetic resonance imaging of myelin: technical developments and challenges. Quant Imaging Med Surg 2020; 10:1186-1203. [PMID: 32550129 PMCID: PMC7276362 DOI: 10.21037/qims-20-541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 04/23/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Eric Y. Chang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Annie Hiniker
- Department of Pathology, University of California San Diego, San Diego, CA, USA
| | - Brian P. Head
- Department of Anesthesiology, University of California San Diego, San Diego, CA, USA
| | - Roland R. Lee
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Graeme M. Bydder
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, CA, USA
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27
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Jang H, Carl M, Ma Y, Searleman AC, Jerban S, Chang EY, Corey-Bloom J, Du J. Inversion recovery zero echo time (IR-ZTE) imaging for direct myelin detection in human brain: a feasibility study. Quant Imaging Med Surg 2020; 10:895-906. [PMID: 32489915 DOI: 10.21037/qims.2020.04.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Myelin alteration is closely associated with neurological diseases such as multiple sclerosis (MS). Unfortunately, due to myelin's extremely short T2* (~0.3 ms or shorter at 3T), it cannot be directly imaged with conventional MR imaging techniques. Recently, ultrashort echo time (UTE) imaging-based methods have been proposed for direct imaging of myelin. In this study, we explore the feasibility and efficacy of inversion recovery prepared zero echo time (IR-ZTE) imaging for direct volumetric imaging of myelin in white matter of the brain in vivo. Methods In the proposed method, an adiabatic IR preparation pulse is used to suppress long T2 white matter signal, followed by dual echo ZTE imaging where the remaining long T2 components, including gray matter, are suppressed by dual echo subtraction. In the implementation of ZTE, the sampling strategy introduced in Water- and Fat-Suppressed Proton Projection MRI (WASPI) was incorporated to acquire the k-space data missing due to the radiofrequency (RF) transmit/receiver switching time. The IR-ZTE sequence was implemented on a 3T clinical MR system and evaluated using a myelin phantom composed of six different myelin concentrations (0% to 20%), a cadaveric human brain, four healthy volunteers, and seven MS patients. Results In the myelin phantom experiment, the ZTE signal intensity showed high linearity to the myelin concentrations (R2=0.98). In the ex vivo and in vivo experiments, the IR-ZTE sequence provided high contrast volumetric imaging of myelin in human brains. The IR-ZTE sequence was able to detect demyelinated foci lesions in all MS patients. Conclusions Adiabatic IR prepared dual echo ZTE imaging allows for direct, volumetric imaging of myelin in white matter of the brain in vivo.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | | | - Yajun Ma
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Adam C Searleman
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Saeed Jerban
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California San Diego, San Diego, CA, USA.,Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, CA, USA
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28
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Ma YJ, Chen Y, Li L, Cai Z, Wei Z, Jerban S, Jang H, Chang EY, Du J. Trabecular bone imaging using a 3D adiabatic inversion recovery prepared ultrashort TE Cones sequence at 3T. Magn Reson Med 2020; 83:1640-1651. [PMID: 31631404 PMCID: PMC6982597 DOI: 10.1002/mrm.28027] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 09/02/2019] [Accepted: 09/12/2019] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate direct imaging of trabecular bone using a 3D adiabatic inversion recovery prepared ultrashort TE cones (3D IR-UTE-Cones) sequence. METHODS The proposed 3D IR-UTE-Cones sequence used a broadband adiabatic inversion pulse together with a short TR/TI combination to suppress signals from long T2 tissues such as muscle and marrow fat, followed by multispoke UTE acquisition to detect signal from short T2 water components in trabecular bone. The feasibility of this technique for robust suppression of long T2 tissues was first demonstrated through numerical simulations. The proposed IR-UTE-Cones sequence was applied to a hip agarose bone phantom and to 6 healthy volunteers for morphologic and quantitative T 2 ∗ and proton density mapping of trabecular bone. RESULTS Numeric simulation suggests that the IR technique with a short TR/TI combination provides sufficient suppression of long T2 tissues with a wide range of T1 s. High contrast imaging of trabecular bone can be achieved ex vivo and in vivo, with fitted T 2 ∗ values of 0.3-0.45 ms and proton densities of 5-9 mol/L. CONCLUSION The 3D IR-UTE-Cones sequence with a short TR/TI combination provides robust suppression of long T2 tissues and allows both selective imaging and quantitative ( T 2 ∗ and proton density) assessment of short T2 water components in trabecular bone in vivo.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
| | - Yanjun Chen
- Department of Radiology, University of California, San Diego, CA
| | - Liang Li
- Department of Radiology, University of California, San Diego, CA
| | - Zhenyu Cai
- Department of Radiology, University of California, San Diego, CA
| | - Zhao Wei
- Department of Radiology, University of California, San Diego, CA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, CA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA
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Weiger M, Froidevaux R, Baadsvik EL, Brunner DO, Rösler MB, Pruessmann KP. Advances in MRI of the myelin bilayer. Neuroimage 2020; 217:116888. [PMID: 32360688 DOI: 10.1016/j.neuroimage.2020.116888] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/26/2020] [Accepted: 04/26/2020] [Indexed: 12/19/2022] Open
Abstract
Myelin plays a key role in the function of the central nervous system and is involved in many neurodegenerative diseases. Hence, depiction of myelin is desired for both research and diagnosis. However, MRI of the lipid bilayer constituting the myelin membrane is hampered by extremely rapid signal decay and cannot be accomplished with conventional sequences. Dedicated short-T2 techniques have therefore been employed, yet with extended sequence timings not well matched to the rapid transverse relaxation in the bilayer, which leads to signal loss and blurring. In the present work, capture and encoding of the ultra-short-T2 signals in the myelin bilayer is considerably improved by employing advanced short-T2 methodology and hardware, in particular a high-performance human-sized gradient insert. The approach is applied to tissue samples excised from porcine brain and in vivo in a human volunteer. It is found that the rapidly decaying non-aqueous components in the brain can indeed be depicted with MRI at useful resolution. As a considerable fraction of these signals is related to the myelin bilayer, the presented approach has strong potential to contribute to myelin research and diagnosis.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Emily Louise Baadsvik
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David Otto Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela Barbara Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas Paul Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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30
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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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31
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Shtangel O, Mezer AA. A phantom system for assessing the effects of membrane lipids on water proton relaxation. NMR IN BIOMEDICINE 2020; 33:e4209. [PMID: 31899589 DOI: 10.1002/nbm.4209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 09/24/2019] [Accepted: 10/13/2019] [Indexed: 06/10/2023]
Abstract
Quantitative MRI (qMRI) is a method for the non-invasive study of brain-structure-associated changes expressed with measurable units. The qMRI-derived parameters have been shown to reflect brain tissue composition such as myelin content. Nevertheless, it remains a major challenge to identify and quantify the contributions of specific molecular components to the MRI signal. Here, we describe a phantom system that can be used to evaluate the contribution of membrane lipids to qMRI-derived parameters. We used a hydration-dehydration dry film technique to formulate liposomes that can be used as a model of the bilayer lipid membrane. The liposomes were comprised of the most abundant types of lipid found in the human brain. We then applied clinically available qMRI techniques with adjusted bias corrections in order to test the ability of the phantom system to estimate multiple qMRI parameters such as proton density (PD), T1 , T2 , T2 * and magnetization transfer. In addition, we accurately measured the phantom sample water fraction (normalized PD). A similar protocol was also applied to the human brain in vivo. The phantom system allows for a reliable estimation of qMRI parameters for phantoms composed of various lipid types using a clinical MRI scanner. We also found a comparable reproducibility between the phantom and in vivo human brain qMRI estimations. To conclude, we have successfully created a biologically relevant liposome phantom system whose lipid composition can be fully controlled. Our lipid system and analysis can be used to measure the contributions to qMRI parameters of membrane lipids found in the human brain under scanning conditions that are relevant to in vivo human brain scans. Such a model system can be used to test the contributions of lipidomic changes in normal and pathological brain states.
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Affiliation(s)
- Oshrat Shtangel
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| | - Aviv A Mezer
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
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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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Ma YJ, Searleman AC, Jang H, Wong J, Chang EY, Corey-Bloom J, Bydder GM, Du J. Whole-Brain Myelin Imaging Using 3D Double-Echo Sliding Inversion Recovery Ultrashort Echo Time (DESIRE UTE) MRI. Radiology 2020; 294:362-374. [PMID: 31746689 PMCID: PMC6996715 DOI: 10.1148/radiol.2019190911] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/21/2019] [Accepted: 08/30/2019] [Indexed: 11/11/2022]
Abstract
Background Signal contamination from long T2 water is a major challenge in direct imaging of myelin with MRI. Nulling of the unwanted long T2 signals can be achieved with an inversion recovery (IR) preparation pulse to null long T2 white matter within the brain. The remaining ultrashort T2 signal from myelin can be detected with an ultrashort echo time (UTE) sequence. Purpose To develop patient-specific whole-brain myelin imaging with a three-dimensional double-echo sliding inversion recovery (DESIRE) UTE sequence. Materials and Methods The DESIRE UTE sequence generates a series of IR images with different inversion times during a single scan. The optimal inversion time for nulling long T2 signal is determined by finding minimal signal on the second echo. Myelin images are generated by subtracting the second echo image from the first UTE image. To validate this method, a prospective study was performed in phantoms, cadaveric brain specimens, healthy volunteers, and patients with multiple sclerosis (MS). A total of 20 healthy volunteers (mean age, 40 years ± 13 [standard deviation], 10 women) and 20 patients with MS (mean age, 58 years ± 8; 15 women) who underwent MRI between November 2017 and February 2019 were prospectively included. Analysis of variance was performed to evaluate the signal difference between MS lesions and normal-appearing white matter in patients with MS. Results High signal intensity and corresponding T2* and T1 of the extracted myelin vesicles provided evidence for direct imaging of ultrashort-T2 myelin protons using the UTE sequence. Gadobenate dimeglumine phantoms with a wide range of T1 values were selectively suppressed with DESIRE UTE. In the ex vivo brain study of MS lesions, signal loss was observed in MS lesions and was conformed with histologic analysis. In the human study, there was a significant reduction in normalized signal intensity in MS lesions compared with that in normal-appearing white matter (0.19 ± 0.10 vs 0.76 ± 0.11, respectively; P < .001). Conclusion The double-echo sliding inversion recovery ultrashort echo time sequence can generate whole-brain myelin images specifically with a clinical 3-T scanner. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Port in this issue.
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Affiliation(s)
- Ya-Jun Ma
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Adam C. Searleman
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Hyungseok Jang
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Jonathan Wong
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Eric Y. Chang
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Jody Corey-Bloom
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Graeme M. Bydder
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
| | - Jiang Du
- From the Departments of Radiology (Y.J.M., A.C.S., H.J., J.W.,
E.Y.C., G.M.B., J.D.) and Neurosciences (J.C.), University of California San
Diego, 9452 Medical Center Dr, La Jolla, CA 92037; and Radiology Service, VA San
Diego Healthcare System, San Diego, Calif (J.W., E.Y.C.)
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34
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Guglielmetti C, Boucneau T, Cao P, Van der Linden A, Larson PEZ, Chaumeil MM. Longitudinal evaluation of demyelinated lesions in a multiple sclerosis model using ultrashort echo time magnetization transfer (UTE-MT) imaging. Neuroimage 2019; 208:116415. [PMID: 31811900 DOI: 10.1016/j.neuroimage.2019.116415] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/16/2019] [Accepted: 11/28/2019] [Indexed: 11/27/2022] Open
Abstract
Alterations in myelin integrity are involved in many neurological disorders and demyelinating diseases, such as multiple sclerosis (MS). Although magnetic resonance imaging (MRI) is the gold standard method to diagnose and monitor MS patients, clinically available MRI protocols show limited specificity for myelin detection, notably in cerebral grey matter areas. Ultrashort echo time (UTE) MRI has shown great promise for direct imaging of lipids and myelin sheaths, and thus holds potential to improve lesion detection. In this study, we used a sequence combining magnetization transfer (MT) with UTE ("UTE-MT", TE = 76 μs) and with short TE ("STE-MT", TE = 3000 μs) to evaluate spatial and temporal changes in brain myelin content in the cuprizone mouse model for MS on a clinical 7 T scanner. During demyelination, UTE-MT ratio (UTE-MTR) and STE-MT ratio (STE-MTR) values were significantly decreased in most white matter and grey matter regions. However, only UTE-MTR detected cortical changes. After remyelination in subcortical and cortical areas, UTE-MTR values remained lower than baseline values, indicating that UTE-MT, but not STE-MT, imaging detected long-lasting changes following a demyelinating event. Next, we evaluated the potential correlations between imaging values and underlying histopathological markers. The strongest correlation was observed between UTE-MTR and percent coverage of myelin basic protein (MBP) immunostaining (r2 = 0.71). A significant, although lower, correlation was observed between STE-MTR and MBP (r2 = 0.48), and no correlation was found between UTE-MTR or STE-MTR and gliosis immunostaining. Interestingly, correlations varied across brain substructures. Altogether, our results demonstrate that UTE-MTR values significantly correlate with myelin content as measured by histopathology, not only in white matter, but also in subcortical and cortical grey matter regions in the cuprizone mouse model for MS. Readily implemented on a clinical 7 T system, this approach thus holds great potential for detecting demyelinating/remyelinating events in both white and grey matter areas in humans. When applied to patients with neurological disorders, including MS patient populations, UTE-MT methods may improve the non-invasive longitudinal monitoring of brain lesions, not only during disease progression but also in response to next generation remyelinating therapies.
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Affiliation(s)
- Caroline Guglielmetti
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; Bio-Imaging Laboratory, Department of Biomedical Sciences, University of Antwerp, 2000, Antwerp, Belgium
| | - Tanguy Boucneau
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Peng Cao
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Annemie Van der Linden
- Bio-Imaging Laboratory, Department of Biomedical Sciences, University of Antwerp, 2000, Antwerp, Belgium
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley and University of California, San Francisco, CA, USA
| | - Myriam M Chaumeil
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley and University of California, San Francisco, CA, USA.
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35
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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36
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Jang H, Ma Y, Searleman AC, Carl M, Corey-Bloom J, Chang EY, Du J. Inversion recovery UTE based volumetric myelin imaging in human brain using interleaved hybrid encoding. Magn Reson Med 2019; 83:950-961. [PMID: 31532032 DOI: 10.1002/mrm.27986] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 07/12/2019] [Accepted: 08/15/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Direct myelin imaging can improve the characterization of myelin-related diseases such as multiple sclerosis. In this study, we explore a novel method to directly image myelin using inversion recovery-prepared hybrid encoding (IR-HE) UTE MRI. METHODS The IR-HE sequence uses an adiabatic inversion pulse to suppress the long T2 white matter signal, followed by 3D dual-echo HE utilizing both single point imaging and radial frequency encoding, for which the subtraction image between 2 echoes reveals the myelin signal with high contrast. To reduce scan time, it is common to obtain multiple spokes per IR. Here, we invented a novel method to improve the HE, adapted for the multi-spoke IR imaging-termed interleaved HE-for which single point imaging encoding is interleaved between radial frequency encodings near nulling point to allow more efficient IR-signal suppression. To evaluate the proposed approach, a computer simulation, myelin phantom experiment, an ex vivo experiment with a cadaveric multiple sclerosis brain, and an in vivo experiment with 8 healthy volunteers and 13 multiple sclerosis patients were performed. RESULTS The computer simulation showed that IR-interleaved HE allows for improved contrast of myelin signal with reduced imaging artifacts. The myelin phantom experiment showed IR-interleaved HE allows direct imaging of myelin lipid with excellent suppression of water signal. In the ex vivo and in vivo experiments, the proposed method demonstrated highly specific imaging of myelin in white matter of the brain. CONCLUSION IR-interleaved HE allows for time-efficient, high-contrast direct myelin imaging and can detect demyelinated lesions in multiple sclerosis patients.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California San Diego, San Diego, California
| | - Adam C Searleman
- Department of Radiology, University of California San Diego, San Diego, California
| | | | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, California
| | - Eric Y Chang
- Department of Radiology, University of California San Diego, San Diego, California.,Radiology Service, VA San Diego Healthcare System, San Diego, California
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, California
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37
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Soustelle L, Antal MC, Lamy J, Rousseau F, Armspach JP, Loureiro de Sousa P. Correlations of quantitative MRI metrics with myelin basic protein (MBP) staining in a murine model of demyelination. NMR IN BIOMEDICINE 2019; 32:e4116. [PMID: 31225675 DOI: 10.1002/nbm.4116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/17/2019] [Accepted: 04/21/2019] [Indexed: 06/09/2023]
Abstract
Myelin imaging in the central nervous system is essential for monitoring pathologies involving white matter alterations. Various quantitative MRI protocols relying on the modeling of the interactions of water protons with myelinated tissues have shown sensitivities in case of myelin disruption. Some extracted model parameters are more sensitive to demyelination, such as the bound pool fraction (f) in quantitative magnetization transfer imaging (qMTI), the radial diffusivity in diffusion tensor imaging (DTI), and the myelin water fraction (MWF) in myelin water imaging (MWI). A 3D ultrashort echo time (UTE) sequence within an appropriate water suppression condition (Diff-UTE) is also considered for the direct visualization of the myelin semi-solid matrix (Diff-UTE normalized signal; rSPF). In this paper, we aimed at assessing the sensitivities and correlations of the parameters mentioned above to an immuno-histological study of the myelin basic protein (MBP) in a murine model of demyelination at 7 T. We demonstrated a high sensitivity of the MRI metrics to demyelination, and strong Spearman correlations in the corpus callosum between histology, macromolecular proton fraction (ρ>0.87) and Diff-UTE signal (ρ>0.76), but moderate ones with radial diffusivity and MWF (|ρ|<0.70).
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Affiliation(s)
- Lucas Soustelle
- Université de Strasbourg, CNRS, ICube, FMTS, Strasbourg, France
| | - Maria C Antal
- Université de Strasbourg, CNRS, ICube, FMTS, Strasbourg, France
| | - Julien Lamy
- Université de Strasbourg, CNRS, ICube, FMTS, Strasbourg, France
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38
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Li Q, Cao X, Ye H, Liao C, He H, Zhong J. Ultrashort echo time magnetic resonance fingerprinting (UTE-MRF) for simultaneous quantification of long and ultrashort T 2 tissues. Magn Reson Med 2019; 82:1359-1372. [PMID: 31131911 DOI: 10.1002/mrm.27812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/27/2019] [Accepted: 04/22/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE To demonstrate an ultrashort echo time magnetic resonance fingerprinting (UTE-MRF) method that allows quantifying relaxation times for muscle and bone in the musculoskeletal system and generating bone enhanced images that mimic CT scans. METHODS A fast imaging steady-state free precession MRF sequence with half pulse excitation and half projection readout was designed to sample fast T2 decay signals. Varying echo time (TE) of a sinusoidal pattern was applied to enhance sensitivity for tissues with short and ultrashort T2 values. The performance of UTE-MRF was evaluated via simulations, phantom, and in vivo experiments. RESULTS A minimal TE of 0.05 ms was achieved. Simulations indicated the sinusoidal TE sampling increased T2 quantification accuracy in the cortical bone and tendon but had little impact on long T2 muscle quantifications. For the rubber phantom, the averaged relaxometries from UTE-MRF (T1 = 162 ms and T2 = 1.07 ms) compared well with the gold standard (T1 = 190 ms and T 2 ∗ = 1.03 ms). For the long T2 agarose phantom, the linear regression slope between UTE-MRF and gold standard was 1.07 (R2 = 0.991) for T1 and 1.04 (R2 = 0.994) for T2 . In vivo experiments showed the detection of the cortical bone (averaged T2 = 1.0 ms) and Achilles tendon (averaged T2 = 15 ms). Scalp structures from the bone enhanced image show high similarity with CT. CONCLUSION The UTE-MRF with sinusoidal TEs can simultaneously quantify T1 , T2 , proton density, and B0 in long, short, even ultrashort T2 musculoskeletal structures. Bone enhanced images can be achieved in the brain with UTE-MRF.
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Affiliation(s)
- Qing Li
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaozhi Cao
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Huihui Ye
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Congyu Liao
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongjian He
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianhui Zhong
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, Zhejiang, China
- Department of Imaging Sciences, University of Rochester, Rochester, New York
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Seifert AC, Umphlett M, Hefti M, Fowkes M, Xu J. Formalin tissue fixation biases myelin-sensitive MRI. Magn Reson Med 2019; 82:1504-1517. [PMID: 31125149 DOI: 10.1002/mrm.27821] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/20/2022]
Abstract
PURPOSE Chemical fixatives such as formalin form cross-links between proteins and affect the relaxation times and diffusion properties of tissue. These fixation-induced changes likely also affect myelin density measurements produced by quantitative magnetization transfer and myelin water imaging. In this work, we evaluate these myelin-sensitive MRI methods for fixation-induced biases. METHODS We perform quantitative magnetization transfer, myelin water imaging, and deuterium oxide-exchanged zero TE imaging on unfixed human spinal cord tissue at 9.4 Tesla and repeat these measurements after 1 day and 31 days of formalin fixation. RESULTS The quantitative magnetization-transfer bound pool fraction increased by 30.7% ± 21.1% after 1 day of fixation and by 42.6% ± 33.9% after 31 days of fixation. Myelin water fraction increased by 39.7% ± 15.5% and 37.0% ± 15.9% at these same time points, and mean T2 of the myelin water pool nearly doubled. Reference-normalized deuterium oxide-exchanged zero TE signal intensity increased by 8.17% ± 6.03% after 31 days of fixation but did not change significantly after 1 day of fixation. After fixation, specimen cross-sectional area decreased by approximately 5%; after correction for shrinkage, changes in deuterium oxide-exchanged zero TE intensity were nearly eliminated. CONCLUSION Bound pool fraction and myelin water fraction are significantly increased by formalin fixation, whereas deuterium oxide-exchanged zero TE intensity is minimally affected. Changes in quantitative magnetization transfer and myelin water imaging may be due in part to delamination and formation of vacuoles in the myelin sheath. Deuterium oxide-exchanged signal intensity may be altered by fixation-induced changes in myelin lipid solid-state 1 H T1 . We urge caution in the comparison of these measurements across subjects or specimens in different states, especially unfixed versus fixed tissue.
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Affiliation(s)
- Alan C Seifert
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Melissa Umphlett
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Marco Hefti
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mary Fowkes
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Junqian Xu
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
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40
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Zu Z. Ratiometric NOE(-1.6) contrast in brain tumors. NMR IN BIOMEDICINE 2018; 31:e4017. [PMID: 30334295 DOI: 10.1002/nbm.4017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/06/2018] [Accepted: 08/24/2018] [Indexed: 06/08/2023]
Abstract
Recently, a new nuclear Overhauser enhancement (NOE)-mediated saturation transfer effect at around -1.6 ppm from water, termed NOE(-1.6), was reported to show hypointense signals in brain tumors. Similar to chemical exchange saturation transfer or magnetization transfer (MT) effects, which depend on the solute pool concentration, the exchange/coupling rate, the solute transverse relaxation rate, etc., the NOE(-1.6) effect should also depend on these factors. Since the exchange rate is relevant to tissue pH, and the coupling rate and the solute transverse relaxation rate are relevant to the motional property of the coupled molecules, further studies to quantify the contribution from only the exchange/coupling rate and the solute transverse relaxation rate are always interesting. The purpose of this paper is to apply a ratiometric approach to the NOE(-1.6) effect to obtain a metric that is more specific to the NOE coupling rate and the solute transverse relaxation rate than the NOE(-1.6) signal amplitude. Simulations indicate that the ratiometric approach allows us to rule out nearly all of the non-specific factors including the solute pool concentration, solute and water longitudinal relaxation rates, direct water saturation, and semi-solid MT effects, and provides a more specific NOE coupling rate- and solute transverse relaxation rate-weighted signal. Animal studies show that the ratiometric NOE(-1.6) decreases dramatically in brain tumors, which suggests that the change in the NOE(-1.6) coupling rate and/or the solute transverse relaxation rate are major contributors to the previously observed hypointense NOE(-1.6) signal in tumors.
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Affiliation(s)
- Zhongliang Zu
- Department of Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science, Nashville, TN, USA
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41
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West KL, Kelm ND, Carson RP, Gochberg DF, Ess KC, Does MD. Myelin volume fraction imaging with MRI. Neuroimage 2018; 182:511-521. [PMID: 28025129 PMCID: PMC5481512 DOI: 10.1016/j.neuroimage.2016.12.067] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/23/2016] [Accepted: 12/22/2016] [Indexed: 11/20/2022] Open
Abstract
MRI is a valuable tool to assess myelin during development and demyelinating disease processes. While multiexponential T2 and quantitative magnetization transfer measures correlate with myelin content, neither provides the total myelin volume fraction. In many cases correlative measures are adequate; but to assess microstructure of myelin, (e.g. calculate the g-ratio using MRI), an accurate measure of myelin volume fraction is imperative. Using a volumetric model of white matter, we relate MRI measures of myelin to absolute measures of myelin volume fraction and compare them to quantitative histology. We assess our approach in control mice along with two models of hypomyelination and one model of hypermyelination and find strong agreement between MRI and histology amongst models. This work investigates the sensitivities of MRI myelin measures to changes in axon geometry and displays promise for estimating g-ratio from MRI.
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Affiliation(s)
- Kathryn L West
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA
| | - Nathaniel D Kelm
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA
| | - Robert P Carson
- Department of Pediatrics, Vanderbilt University School of Medicine, USA; Department of Neurology, Vanderbilt University School of Medicine, USA
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA; Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University School of Medicine, USA; Department of Neurology, Vanderbilt University School of Medicine, USA
| | - Mark D Does
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA; Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, USA; Department of Electrical Engineering, Vanderbilt University, USA.
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42
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Fan SJ, Wong J, Cheng X, Ma YJ, Chang EY, Du J, Shah SB. Feasibility of quantitative ultrashort echo time (UTE)-based methods for MRI of peripheral nerve. NMR IN BIOMEDICINE 2018; 31:e3948. [PMID: 30011103 PMCID: PMC6310234 DOI: 10.1002/nbm.3948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/19/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
Peripheral nerves are a composite tissue consisting of neurovascular elements packaged within a well-organized extracellular matrix. Their composition, size, and anatomy render nerves a challenging medical imaging target. In contrast to morphological MRI, which represents the predominant approach to nerve imaging, quantitative MRI sequences can provide information regarding tissue composition. Here, we applied standard clinical Carr-Purcell-Meiboom-Gill (CPMG) and experimental three-dimensional (3D) ultrashort echo time (UTE) Cones sequences for quantitative nerve imaging including T2 measurement with single-component analysis, T2 * measurement with single-component and bi-component analyses, and magnetization transfer ratio (MTR) analysis. We demonstrated the feasibility and the high quality of single-component T2 *, bi-component T2 *, and MTR approaches to analyze nerves imaged with clinically deployed 3D UTE Cones pulse sequences. For 24 single fascicles from eight nerves, we measured a mean single-component T2 * of 22.6 ±8.9 ms, and a short T2 * component (STC) with a mean T2 * of 1.7 ±1.0 ms and a mean fraction of (6.74 ±4.31)% in bi-component analysis. For eight whole nerves, we measured a mean single-component T2 * of 16.7 ±2.2 ms, and an STC with a mean T2 * of 3.0 ±1.0 ms and a mean fraction of (15.56 ±7.07)% in bi-component analysis. For nine fascicles from three healthy nerves, we measured a mean MTR of (25.2 ±1.9)% for single fascicles and a mean MTR of (23.6 ±0.9)% for whole nerves. No statistically significant correlation was observed between any MRI parameter and routine histological outcomes, perhaps due to the small sample size and lack of apparent sample pathology. Overall, we have successfully demonstrated the feasibility of measuring quantitative MR outcomes ex vivo, which might reflect features of nerve structure and macromolecular content. These methods should be validated comprehensively on a larger and more diverse set of nerve samples, towards the interpretation of in vivo outcomes. These approaches have new and broad implications for the management of nerve disease, injury, and repair.
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Affiliation(s)
- Shu-Juan Fan
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Jonathan Wong
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Xin Cheng
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Ya-Jun Ma
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Sameer B Shah
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
- Departments of Orthopaedic Surgery and Bioengineering, University of California, San Diego, La Jolla, CA, USA
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Laule C, Moore GW. Myelin water imaging to detect demyelination and remyelination and its validation in pathology. Brain Pathol 2018; 28:750-764. [PMID: 30375119 PMCID: PMC8028667 DOI: 10.1111/bpa.12645] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/11/2022] Open
Abstract
Damage to myelin is a key feature of multiple sclerosis (MS) pathology. Magnetic resonance imaging (MRI) has revolutionized our ability to detect and monitor MS pathology in vivo. Proton density, T1 and T2 can provide qualitative contrast weightings that yield superb in vivo visualization of central nervous system tissue and have proved invaluable as diagnostic and patient management tools in MS. However, standard clinical MR methods are not specific to the types of tissue damage they visualize, and they cannot detect subtle abnormalities in tissue that appears otherwise normal on conventional MRIs. Myelin water imaging is an MR method that provides in vivo measurement of myelin. Histological validation work in both human brain and spinal cord tissue demonstrates a strong correlation between myelin water and staining for myelin, validating myelin water as a marker for myelin. Myelin water varies throughout the brain and spinal cord in healthy controls, and shows good intra- and inter-site reproducibility. MS plaques show variably decreased myelin water fraction, with older lesions demonstrating the greatest myelin loss. Longitudinal study of myelin water can provide insights into the dynamics of demyelination and remyelination in plaques. Normal appearing brain and spinal cord tissues show reduced myelin water, an abnormality which becomes progressively more evident over a timescale of years. Diffusely abnormal white matter, which is evident in 20%-25% of MS patients, also shows reduced myelin water both in vivo and postmortem, and appears to originate from a primary lipid abnormality with relative preservation of myelin proteins. Active research is ongoing in the quest to refine our ability to image myelin and its perturbations in MS and other disorders of the myelin sheath.
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Affiliation(s)
- Cornelia Laule
- RadiologyUniversity of British ColumbiaVancouverBCCanada
- Pathology & Laboratory MedicineUniversity of British ColumbiaVancouverBCCanada
- Physics & AstronomyUniversity of British ColumbiaVancouverBCCanada
- International Collaboration on Repair Discoveries (ICORD)University of British ColumbiaVancouverBCCanada
| | - G.R. Wayne Moore
- Pathology & Laboratory MedicineUniversity of British ColumbiaVancouverBCCanada
- International Collaboration on Repair Discoveries (ICORD)University of British ColumbiaVancouverBCCanada
- Medicine (Neurology)University of British ColumbiaVancouverBCCanada
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44
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Guenette JP, Seethamraju RT, Jayender J, Corrales CE, Lee TC. MR Imaging of the Facial Nerve through the Temporal Bone at 3T with a Noncontrast Ultrashort Echo Time Sequence. AJNR Am J Neuroradiol 2018; 39:1903-1906. [PMID: 30139756 DOI: 10.3174/ajnr.a5754] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/03/2018] [Indexed: 11/07/2022]
Abstract
The pointwise encoding time reduction with radial acquisition (PETRA) ultrashort echo time MR imaging sequence at 3T enables visualization of the facial nerve from the brain stem, through the temporal bone, to the stylomastoid foramen without intravenous contrast. Use of the PETRA sequence, or other ultrashort echo time sequences, should be considered in the MR imaging evaluation of certain skull base tumors and perhaps other facial nerve and temporal bone pathologies.
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Affiliation(s)
- J P Guenette
- From the Division of Neuroradiology (J.P.G., J.J., T.C.L.)
| | - R T Seethamraju
- Siemens Medical Solutions USA, Inc. (R.T.S.), Boston, Massachusetts
| | - J Jayender
- From the Division of Neuroradiology (J.P.G., J.J., T.C.L.)
| | - C E Corrales
- Division of Otolaryngology-Head and Neck Surgery (C.E.C.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - T C Lee
- From the Division of Neuroradiology (J.P.G., J.J., T.C.L.)
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45
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Fan SJ, Ma Y, Zhu Y, Searleman A, Szeverenyi NM, Bydder GM, Du J. Yet more evidence that myelin protons can be directly imaged with UTE sequences on a clinical 3T scanner: Bicomponent T2* analysis of native and deuterated ovine brain specimens. Magn Reson Med 2018; 80:538-547. [PMID: 29271083 PMCID: PMC5910230 DOI: 10.1002/mrm.27052] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/05/2017] [Accepted: 11/29/2017] [Indexed: 01/15/2023]
Abstract
PURPOSE UTE sequences with a minimal nominal TE of 8 µs have shown promise for direct imaging of myelin protons (T2 , < 1 ms). However, there is still debate about the efficiency of 2D slice-selective UTE sequences in exciting myelin protons because the half excitation pulses used in these sequences have a relatively long duration (e.g., 0.3-0.6 ms). Here, we compared UTE and inversion-recovery (IR) UTE sequences used with either hard or half excitation pulses (durations 32 µs or 472 µs, respectively) for imaging myelin in native and deuterated ovine brain at 3T. METHODS Freshly frozen ovine brains were dissected into ∼2 mm-thick pure white matter and ∼3 to 8 mm-thick cerebral hemisphere specimens, which were imaged before and/or after different immersion time in deuterium oxide. RESULTS Bicomponent T2* analysis of UTE signals obtained with hard excitation pulses detected an ultrashort T2 component (STC) fraction (fS ) of 0% to 10% in native specimens, and up to ∼86% in heavily deuterated specimens. fS values were significantly affected by the TIs used in IR-UTE sequences with either hard or half excitation pulses in native specimens but not in heavily deuterated specimens. The STC T2* was in the range of 150 to 400 µs in all UTE and IR-UTE measurements obtained with either hard or half excitation pulses. CONCLUSION Our results further support myelin protons as the major source of the ultrashort T2* signals seen on IR-UTE images and demonstrate the potential of IR-UTE sequences with half excitation pulses for directly imaging myelin using clinical scanners. Magn Reson Med 80:538-547, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Shu-Juan Fan
- Department of Radiology, University of California, San Diego
| | - Yajun Ma
- Department of Radiology, University of California, San Diego
| | - Yanchun Zhu
- Department of Radiology, University of California, San Diego
| | - Adam Searleman
- Department of Radiology, University of California, San Diego
| | | | | | - Jiang Du
- Department of Radiology, University of California, San Diego
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Ma YJ, Zhu Y, Lu X, Carl M, Chang EY, Du J. Short T 2 imaging using a 3D double adiabatic inversion recovery prepared ultrashort echo time cones (3D DIR-UTE-Cones) sequence. Magn Reson Med 2018; 79:2555-2563. [PMID: 28913879 PMCID: PMC5821562 DOI: 10.1002/mrm.26908] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/22/2017] [Accepted: 08/16/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate high contrast imaging of short T2 tissues with a three-dimensional double adiabatic inversion recovery prepared ultrashort echo time Cones (3D DIR-UTE-Cones) sequence. METHODS The sequence used two sequential adiabatic inversion pulses to suppress signals from long T2 tissues, followed by multispoke UTE acquisition to detect signals from short T2 tissues. The two adiabatic inversion pulses are identical with a center frequency located at the water peak, but the spectral width is broad enough to cover both water and fat frequencies. The feasibility of this technique was demonstrated through numerical simulation and phantom studies. Finally, DIR-UTE-Cones was applied to three healthy volunteers to image cortical bone, patellar tendon, and Achilles tendon. T2* was also measured via single-component exponential fitting. RESULTS Numerical simulation suggests that the DIR technique provides perfect nulling of muscle and fat as well as efficient suppression of other long T2 tissues with T1 values between fat and water or those above water. Excellent image contrast can be achieved with DIR-UTE-Cones for the short T2 tissues, with fitted T2* values of 0.28-0.38 ms for cortical bone, 0.56 ± 0.07 ms for the patella tendon, and 0.45 ± 0.06 ms for the Achilles tendon, respectively. CONCLUSION The 3D DIR-UTE-Cones sequence provides robust suppression of long T2 tissues and allows selective imaging as well as T2* measurement of short T2 tissues such as cortical bone, patellar tendon, and the Achilles tendon. Magn Reson Med 79:2555-2563, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
| | - Yanchun Zhu
- Department of Radiology, University of California, San Diego, CA
| | - Xing Lu
- Department of Radiology, University of California, San Diego, CA
| | | | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA
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Ercan E, Varma G, Mädler B, Dimitrov IE, Pinho MC, Xi Y, Wagner BC, Davenport EM, Maldjian JA, Alsop DC, Lenkinski RE, Vinogradov E. Microstructural correlates of 3D steady-state inhomogeneous magnetization transfer (ihMT) in the human brain white matter assessed by myelin water imaging and diffusion tensor imaging. Magn Reson Med 2018; 80:2402-2414. [PMID: 29707813 DOI: 10.1002/mrm.27211] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 02/05/2023]
Abstract
PURPOSE To compare the recently introduced inhomogeneous magnetization transfer (ihMT) technique with more established MRI techniques including myelin water imaging (MWI) and diffusion tensor imaging (DTI), and to evaluate the microstructural attributes correlating with this new contrast method in the human brain white matter. METHODS Eight adult healthy volunteers underwent T1 -weighted, ihMT, MWI, and DTI imaging on a 3T human scanner. The ihMT ratio (ihMTR), myelin water fraction (MWF), fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD), and mean diffusivity (MD) values were calculated from different white matter tracts. The angle ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>θ</mml:mi></mml:math> ) between the directions of the principal eigenvector, as measured by DTI, and the main magnetic field was calculated for all voxels from various fiber tracts. The ihMTR was correlated with MWF and DTI metrics. RESULTS A strong correlation was found between ihMTR and MWF (ρ = 0.77, P < 0.0001). This was followed by moderate to weak correlations between ihMTR and DTI metrics: RD (ρ = -0.30, P < 0.0001), FA (ρ = 0.20, P < 0.0001), MD (ρ = -0.19, P < 0.0001), AD (ρ = 0.02, P < 0.0001). A strong correlation was found between ihMTR and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>θ</mml:mi></mml:math> (ρ = -0.541, P < 0.0001). CONCLUSION The strong correlation with myelin water imaging and its low coefficient of variation suggest that ihMT has the potential to become a new structural imaging marker of myelin. The substantial orientational dependence of ihMT should be taken into account when evaluating and quantitatively interpreting ihMT results.
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Affiliation(s)
- Ece Ercan
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gopal Varma
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | | | - Ivan E Dimitrov
- Philips Healthcare, Gainesville, Florida.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Marco C Pinho
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yin Xi
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Benjamin C Wagner
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Elizabeth M Davenport
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Joseph A Maldjian
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David C Alsop
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Robert E Lenkinski
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Elena Vinogradov
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
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48
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MRI gradient-echo phase contrast of the brain at ultra-short TE with off-resonance saturation. Neuroimage 2018; 175:1-11. [PMID: 29604452 DOI: 10.1016/j.neuroimage.2018.03.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/07/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023] Open
Abstract
Larmor-frequency shift or image phase measured by gradient-echo sequences has provided a new source of MRI contrast. This contrast is being used to study both the structure and function of the brain. So far, phase images of the brain have been largely obtained at long echo times as maximum phase signal-to-noise ratio (SNR) is achieved at TE = T2* (∼40 ms at 3T). The structures of the brain, however, are compartmentalized and complex with a wide range of signal relaxation times. At such long TE, the short-T2 components are largely attenuated and contribute minimally to phase contrast. The purpose of this study was to determine whether proton gradient-echo images of the brain exhibit phase contrast at ultra-short TE (UTE). Our data showed that UTE images acquired at 7 T without off-resonance saturation do not contain significant phase contrast between gray and white matter. However, UTE images of the brain can attain strong phase contrast even at a nominal TE of 106 μs by using off-resonance RF saturation pulses, which provide direct saturation of ultra-short-T2 components and indirect saturation of longer-T2 components via magnetization transfer. In addition, phase contrast between gray and white matter acquired at UTE with off-resonance saturation is reversed compared to that of the long-T2 signals acquired at long TEs. This finding opens up a potential new way to manipulate image phase contrast of the brain. By accessing short and ultra-short-T2 species, MRI phase images may further improve the characterization of tissue microstructure in the brain.
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Soustelle L, Lamy J, Rousseau F, Armspach JP, Loureiro de Sousa P. A diffusion-based method for long-T2suppression in steady state sequences: Validation and application for 3D-UTE imaging. Magn Reson Med 2017; 80:548-559. [DOI: 10.1002/mrm.27057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Lucas Soustelle
- Université de Strasbourg, CNRS, ICube, FMTS; Strasbourg France
| | - Julien Lamy
- Université de Strasbourg, CNRS, ICube, FMTS; Strasbourg France
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Boucneau T, Cao P, Tang S, Han M, Xu D, Henry RG, Larson PEZ. In vivo characterization of brain ultrashort-T 2 components. Magn Reson Med 2017; 80:726-735. [PMID: 29194734 DOI: 10.1002/mrm.27037] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 12/22/2022]
Abstract
PURPOSE Recent nuclear magnetic resonance and MRI studies have measured a fast-relaxing signal component with T2∗<1 ms in white matter and myelin extracts. In ex vivo studies, evidence suggests that a large fraction of this component directly arises from bound protons in the myelin phospholipid membranes. Based on these results, this ultrashort-T2 component in nervous tissue is a new potential imaging biomarker of myelination, which plays a critical role in neuronal signal conduction across the brain and loss or degradation of myelin is a key feature of many neurological disorders. The goal of this work was to characterize the relaxation times and frequency shifts of ultrashort-T2 components in the human brain. METHODS This required development of an ultrashort echo time relaxometry acquisition strategy and fitting procedure for robust measurements in the presence of ultrashort T2∗ relaxation times and large frequency shifts. RESULTS We measured an ultrashort-T2 component in healthy volunteers with a median T2∗ between 0.5-0.7 ms at 3T and 0.2-0.3 ms at 7T as well as an approximately -3 ppm frequency shift from water. CONCLUSION To our knowledge, this is the first time a chemical shift of the ultrashort-T2 brain component has been measured in vivo. This chemical shift, at around 1.7 ppm, is similar to the primary resonance of most lipids, indicating that much of the ultrashort-T2 component observed in vivo arises from bound protons in the myelin phospholipid membranes. Magn Reson Med 80:726-735, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Tanguy Boucneau
- Department of Physics, Ecole Normale Supérieure de Cachan, Cachan, France
| | - Peng Cao
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Shuyu Tang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Misung Han
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Duan Xu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Roland G Henry
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Department of Neurology, University of California, San Francisco, San Francisco, California, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, California, USA
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