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Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines

PURPOSE: To develop new concepts for minimum electric‐field (E‐field) gradient design, and to define the extents to which E‐field can be reduced in gradient design while maintaining a desired imaging performance. METHODS: Efficient calculation of induced electric field in simplified patient models w...

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Autores principales: Roemer, Peter B., Rutt, Brian K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049068/
https://www.ncbi.nlm.nih.gov/pubmed/33565135
http://dx.doi.org/10.1002/mrm.28681
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author Roemer, Peter B.
Rutt, Brian K.
author_facet Roemer, Peter B.
Rutt, Brian K.
author_sort Roemer, Peter B.
collection PubMed
description PURPOSE: To develop new concepts for minimum electric‐field (E‐field) gradient design, and to define the extents to which E‐field can be reduced in gradient design while maintaining a desired imaging performance. METHODS: Efficient calculation of induced electric field in simplified patient models was integrated into gradient design software, allowing constraints to be placed on the peak E‐field. Gradient coils confined to various build envelopes were designed with minimum E‐fields subject to standard magnetic field constraints. We examined the characteristics of E‐field‐constrained gradients designed for imaging the head and body and the importance of asymmetry and concomitant fields in achieving these solutions. RESULTS: For transverse gradients, symmetric solutions create high levels of E‐fields in the shoulder region, while fully asymmetric solutions create high E‐fields on the top of the head. Partially asymmetric solutions result in the lowest E‐fields, balanced between shoulders and head and resulting in factors of 1.8 to 2.8 reduction in E‐field for x‐gradient and y‐gradient coils, respectively, when compared with the symmetric designs of identical gradient distortion. CONCLUSIONS: We introduce a generalized method for minimum E‐field gradient design and define the theoretical limits of magnetic energy and peak E‐field for gradient coils of arbitrary cylindrical geometry.
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spelling pubmed-80490682021-04-20 Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines Roemer, Peter B. Rutt, Brian K. Magn Reson Med Full Papers—Hardware and Instrumentation PURPOSE: To develop new concepts for minimum electric‐field (E‐field) gradient design, and to define the extents to which E‐field can be reduced in gradient design while maintaining a desired imaging performance. METHODS: Efficient calculation of induced electric field in simplified patient models was integrated into gradient design software, allowing constraints to be placed on the peak E‐field. Gradient coils confined to various build envelopes were designed with minimum E‐fields subject to standard magnetic field constraints. We examined the characteristics of E‐field‐constrained gradients designed for imaging the head and body and the importance of asymmetry and concomitant fields in achieving these solutions. RESULTS: For transverse gradients, symmetric solutions create high levels of E‐fields in the shoulder region, while fully asymmetric solutions create high E‐fields on the top of the head. Partially asymmetric solutions result in the lowest E‐fields, balanced between shoulders and head and resulting in factors of 1.8 to 2.8 reduction in E‐field for x‐gradient and y‐gradient coils, respectively, when compared with the symmetric designs of identical gradient distortion. CONCLUSIONS: We introduce a generalized method for minimum E‐field gradient design and define the theoretical limits of magnetic energy and peak E‐field for gradient coils of arbitrary cylindrical geometry. John Wiley and Sons Inc. 2021-02-09 2021-07 /pmc/articles/PMC8049068/ /pubmed/33565135 http://dx.doi.org/10.1002/mrm.28681 Text en © 2021 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Full Papers—Hardware and Instrumentation
Roemer, Peter B.
Rutt, Brian K.
Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title_full Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title_fullStr Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title_full_unstemmed Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title_short Minimum electric‐field gradient coil design: Theoretical limits and practical guidelines
title_sort minimum electric‐field gradient coil design: theoretical limits and practical guidelines
topic Full Papers—Hardware and Instrumentation
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049068/
https://www.ncbi.nlm.nih.gov/pubmed/33565135
http://dx.doi.org/10.1002/mrm.28681
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