Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T.
Knowledge of the transmission field (B1(+)) of radio-frequency coils is crucial for high field (B0 = 3.0 T) and ultrahigh field (B0 ≥7.0 T) magnetic resonance applications to overcome constraints dictated by electrodynamics in the short wavelength regime with the ultimate goal to improve the image...
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Public Library of Science (PLoS)
2013-01-01
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Series: | PLoS ONE |
Online Access: | http://europepmc.org/articles/PMC3589447?pdf=render |
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author | Flavio Carinci Davide Santoro Federico von Samson-Himmelstjerna Tomasz Dawid Lindel Matthias Alexander Dieringer Thoralf Niendorf |
author_facet | Flavio Carinci Davide Santoro Federico von Samson-Himmelstjerna Tomasz Dawid Lindel Matthias Alexander Dieringer Thoralf Niendorf |
author_sort | Flavio Carinci |
collection | DOAJ |
description | Knowledge of the transmission field (B1(+)) of radio-frequency coils is crucial for high field (B0 = 3.0 T) and ultrahigh field (B0 ≥7.0 T) magnetic resonance applications to overcome constraints dictated by electrodynamics in the short wavelength regime with the ultimate goal to improve the image quality. For this purpose B1(+) mapping methods are used, which are commonly magnitude-based. In this study an analysis of five phase-based methods for three-dimensional mapping of the B1(+) field is presented. The five methods are implemented in a 3D gradient-echo technique. Each method makes use of different RF-pulses (composite or off-resonance pulses) to encode the effective intensity of the B1(+) field into the phase of the magnetization. The different RF-pulses result in different trajectories of the magnetization, different use of the transverse magnetization and different sensitivities to B1(+) inhomogeneities and frequency offsets, as demonstrated by numerical simulations. The characterization of the five methods also includes phantom experiments and in vivo studies of the human brain at 3.0 T and at 7.0 T. It is shown how the characteristics of each method affect the quality of the B1(+) maps. Implications for in vivo B1(+) mapping at 3.0 T and 7.0 T are discussed. |
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id | doaj.art-7b85bd1e5a1442fea86b7f0532f69c7b |
institution | Directory Open Access Journal |
issn | 1932-6203 |
language | English |
last_indexed | 2024-12-10T23:21:01Z |
publishDate | 2013-01-01 |
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spelling | doaj.art-7b85bd1e5a1442fea86b7f0532f69c7b2022-12-22T01:29:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0183e5798210.1371/journal.pone.0057982Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T.Flavio CarinciDavide SantoroFederico von Samson-HimmelstjernaTomasz Dawid LindelMatthias Alexander DieringerThoralf NiendorfKnowledge of the transmission field (B1(+)) of radio-frequency coils is crucial for high field (B0 = 3.0 T) and ultrahigh field (B0 ≥7.0 T) magnetic resonance applications to overcome constraints dictated by electrodynamics in the short wavelength regime with the ultimate goal to improve the image quality. For this purpose B1(+) mapping methods are used, which are commonly magnitude-based. In this study an analysis of five phase-based methods for three-dimensional mapping of the B1(+) field is presented. The five methods are implemented in a 3D gradient-echo technique. Each method makes use of different RF-pulses (composite or off-resonance pulses) to encode the effective intensity of the B1(+) field into the phase of the magnetization. The different RF-pulses result in different trajectories of the magnetization, different use of the transverse magnetization and different sensitivities to B1(+) inhomogeneities and frequency offsets, as demonstrated by numerical simulations. The characterization of the five methods also includes phantom experiments and in vivo studies of the human brain at 3.0 T and at 7.0 T. It is shown how the characteristics of each method affect the quality of the B1(+) maps. Implications for in vivo B1(+) mapping at 3.0 T and 7.0 T are discussed.http://europepmc.org/articles/PMC3589447?pdf=render |
spellingShingle | Flavio Carinci Davide Santoro Federico von Samson-Himmelstjerna Tomasz Dawid Lindel Matthias Alexander Dieringer Thoralf Niendorf Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. PLoS ONE |
title | Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. |
title_full | Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. |
title_fullStr | Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. |
title_full_unstemmed | Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. |
title_short | Characterization of phase-based methods used for transmission field uniformity mapping: a magnetic resonance study at 3.0 T and 7.0 T. |
title_sort | characterization of phase based methods used for transmission field uniformity mapping a magnetic resonance study at 3 0 t and 7 0 t |
url | http://europepmc.org/articles/PMC3589447?pdf=render |
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