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Low‐field MRI: An MR physics perspective

Historically, clinical MRI started with main magnetic field strengths in the ∼0.05–0.35T range. In the past 40 years there have been considerable developments in MRI hardware, with one of the primary ones being the trend to higher magnetic fields. While resulting in large improvements in data qualit...

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Detalles Bibliográficos
Autores principales: Marques, José P., Simonis, Frank F.J., Webb, Andrew G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley & Sons, Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590434/
https://www.ncbi.nlm.nih.gov/pubmed/30637943
http://dx.doi.org/10.1002/jmri.26637
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author Marques, José P.
Simonis, Frank F.J.
Webb, Andrew G.
author_facet Marques, José P.
Simonis, Frank F.J.
Webb, Andrew G.
author_sort Marques, José P.
collection PubMed
description Historically, clinical MRI started with main magnetic field strengths in the ∼0.05–0.35T range. In the past 40 years there have been considerable developments in MRI hardware, with one of the primary ones being the trend to higher magnetic fields. While resulting in large improvements in data quality and diagnostic value, such developments have meant that conventional systems at 1.5 and 3T remain relatively expensive pieces of medical imaging equipment, and are out of the financial reach for much of the world. In this review we describe the current state‐of‐the‐art of low‐field systems (defined as 0.25–1T), both with respect to its low cost, low foot‐print, and subject accessibility. Furthermore, we discuss how low field could potentially benefit from many of the developments that have occurred in higher‐field MRI. In the first section, the signal‐to‐noise ratio (SNR) dependence on the static magnetic field and its impact on the achievable contrast, resolution, and acquisition times are discussed from a theoretical perspective. In the second section, developments in hardware (eg, magnet, gradient, and RF coils) used both in experimental low‐field scanners and also those that are currently in the market are reviewed. In the final section the potential roles of new acquisition readouts, motion tracking, and image reconstruction strategies, currently being developed primarily at higher fields, are presented. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019.
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spelling pubmed-65904342019-07-08 Low‐field MRI: An MR physics perspective Marques, José P. Simonis, Frank F.J. Webb, Andrew G. J Magn Reson Imaging Review Articles Historically, clinical MRI started with main magnetic field strengths in the ∼0.05–0.35T range. In the past 40 years there have been considerable developments in MRI hardware, with one of the primary ones being the trend to higher magnetic fields. While resulting in large improvements in data quality and diagnostic value, such developments have meant that conventional systems at 1.5 and 3T remain relatively expensive pieces of medical imaging equipment, and are out of the financial reach for much of the world. In this review we describe the current state‐of‐the‐art of low‐field systems (defined as 0.25–1T), both with respect to its low cost, low foot‐print, and subject accessibility. Furthermore, we discuss how low field could potentially benefit from many of the developments that have occurred in higher‐field MRI. In the first section, the signal‐to‐noise ratio (SNR) dependence on the static magnetic field and its impact on the achievable contrast, resolution, and acquisition times are discussed from a theoretical perspective. In the second section, developments in hardware (eg, magnet, gradient, and RF coils) used both in experimental low‐field scanners and also those that are currently in the market are reviewed. In the final section the potential roles of new acquisition readouts, motion tracking, and image reconstruction strategies, currently being developed primarily at higher fields, are presented. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019. John Wiley & Sons, Inc. 2019-01-13 2019-06 /pmc/articles/PMC6590434/ /pubmed/30637943 http://dx.doi.org/10.1002/jmri.26637 Text en © 2019 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Review Articles
Marques, José P.
Simonis, Frank F.J.
Webb, Andrew G.
Low‐field MRI: An MR physics perspective
title Low‐field MRI: An MR physics perspective
title_full Low‐field MRI: An MR physics perspective
title_fullStr Low‐field MRI: An MR physics perspective
title_full_unstemmed Low‐field MRI: An MR physics perspective
title_short Low‐field MRI: An MR physics perspective
title_sort low‐field mri: an mr physics perspective
topic Review Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590434/
https://www.ncbi.nlm.nih.gov/pubmed/30637943
http://dx.doi.org/10.1002/jmri.26637
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