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@ARTICLE{Egger:305028,
author = {N. Egger and L. Ruck and S. Nagelstraßer and J. Schirmer
and S. Wildenberg and A. Bitz and J. Herrler and S.
Schmitter$^*$ and M. Uder and A. Nagel$^*$},
title = {{E}valuation of an interleaved acquisition scheme for
improved robustness of channel-wise relative {B}1 + mapping
at 7 {T}.},
journal = {Magnetic resonance in medicine},
volume = {nn},
issn = {1522-2594},
address = {New York, NY [u.a.]},
publisher = {Wiley-Liss},
reportid = {DKFZ-2025-02010},
pages = {nn},
year = {2025},
note = {#LA:E020#/ epub},
abstract = {The purpose was to evaluate, whether an interleaved
acquisition scheme for a fast relative B 1 + $$
{\mathrm{B}}_1^{+} $$ 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 + $$
{\mathrm{B}}_1^{+} $$ 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 + $$ {\mathrm{B}}_1^{+}
$$ 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 +
$$ {\mathrm{B}}_1^{+} $$ data. Additionally, validation
measurements of relative B 1 + $$ {\mathrm{B}}_1^{+} $$ 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 + $$ {\mathrm{B}}_1^{+} $$ 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 + $$ {\mathrm{B}}_1^{+} $$ maps
extends the range of the linear FA regime, reducing the
likelihood of errors and increasing the robustness of the
approach.},
keywords = {7 Tesla (Other) / B1+ mapping (Other) / heart (Other) /
parallel transmission (Other) / prostate (Other) /
ultra‐high field (Other)},
cin = {E020},
ddc = {610},
cid = {I:(DE-He78)E020-20160331},
pnm = {315 - Bildgebung und Radioonkologie (POF4-315)},
pid = {G:(DE-HGF)POF4-315},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:41024603},
doi = {10.1002/mrm.70101},
url = {https://inrepo02.dkfz.de/record/305028},
}