TY  - JOUR
AU  - Egger, Nico
AU  - Ruck, Laurent
AU  - Nagelstraßer, Sophia
AU  - Schirmer, Judith
AU  - Wildenberg, Saskia
AU  - Bitz, Andreas
AU  - Herrler, Jürgen
AU  - Schmitter, Sebastian
AU  - Uder, Michael
AU  - Nagel, Armin
TI  - Evaluation of an interleaved acquisition scheme for improved robustness of channel-wise relative B1 + mapping at 7 T.
JO  - Magnetic resonance in medicine
VL  - nn
SN  - 1522-2594
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DKFZ-2025-02010
SP  - nn
PY  - 2025
N1  - #LA:E020#/ epub
AB  - The purpose was to evaluate, whether an interleaved acquisition scheme for a fast relative B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  mapping method at 7 T reduces the likelihood of errors from exceeding the linear flip angle (FA) regime compared to a conventional sequential acquisition.Simulations of a channel-wise relative B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  mapping sequence were performed for sequential and interleaved acquisition schemes at different reference voltages (≙ different FAs). The simulations were performed for a phantom, the heart and the prostate and were based on 7 T ground-truth (GT) B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  data acquired with an actual FA imaging sequence (phantom) or obtained from electromagnetic field simulations (heart/prostate). Acquisition schemes were evaluated based on their signal linearity by calculating a normalized mean FA error between simulated signal intensities and GT B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  data. Additionally, validation measurements of relative B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  maps with the sequential and interleaved acquisition schemes were acquired for the phantom.Validation measurements showed a good agreement with the simulation results for both acquisition schemes and displayed stronger deviations to the GT B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  data for the sequential scheme. The quantitative evaluation yielded higher FA errors for the sequential acquisition scheme for all three regions and all simulated reference voltages. At the same level of error, mean signals were higher for the interleaved acquisition scheme in all cases. Differences between interleaved and sequential acquisition schemes were most pronounced in the steady-state.An interleaved acquisition of channel-wise relative B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  maps extends the range of the linear FA regime, reducing the likelihood of errors and increasing the robustness of the approach.
KW  - 7 Tesla (Other)
KW  - B1+ mapping (Other)
KW  - heart (Other)
KW  - parallel transmission (Other)
KW  - prostate (Other)
KW  - ultra‐high field (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:41024603
DO  - DOI:10.1002/mrm.70101
UR  - https://inrepo02.dkfz.de/record/305028
ER  -