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@ARTICLE{Obriot:282540,
author = {Obriot, Joseph and Mauconduit, Franck and Gras, Vincent and
Giliyar Radhakrishna, Chaithya and Bertrait, Maxime and
Ehses, Philipp and Stirnberg, Rüdiger and Le Ster, Caroline
and Boulant, Nicolas},
title = {{O}n the {I}mpact of {A}rtifacts {I}nduced by {M}ismatches
{B}etween {A}uto‐{C}alibration {S}ignal and {A}ccelerated
3{D} {GRE} {D}ata at 11.7{T}},
journal = {Magnetic resonance in medicine},
volume = {AOP},
issn = {1522-2594},
address = {New York, NY [u.a.]},
publisher = {Wiley-Liss},
reportid = {DZNE-2025-01303},
pages = {mrm.70127},
year = {2025},
abstract = {PurposeThe study aims at investigating field inhomogeneity
artifacts arising from remote locations in the FOV and
encountered in accelerated 3D gradient-recalled echo (GRE)
sequences at ultra-high field, and at providing mitigation
strategies.MethodsMeasurements were conducted at 11.7T using
a head-shaped phantom and an accelerated 3D GRE sequence
with either integrated or external auto-calibration signal
(ACS) lines. Simulations were performed to reproduce the
artifacts. The effects of varying GRAPPA reconstruction
parameters (kernel size and regularization) were also
examined.Results field inhomogeneities located outside the
shimmed region of interest (i.e., the brain) were observed
to return ripple-like artifacts within this region,
particularly at long echo times. The simulation results
support these findings, and the idea that the observed
artifact originates from a mismatch between ACS and
accelerated data due to intra-voxel dephasing at different
resolutions (ACS lines having an intrinsically lower
resolution). The short echo time enabled by external (i.e.,
preacquired) ACS lines reduced artifacts compared to
integrated ones. Varying GRAPPA kernel sizes and increasing
the number of ACS lines can improve image quality, yet
without full compensation.ConclusionThis study highlights
ripple-like artifacts amplified with field strength and
arising from a lack of coherence between the ACS and imaging
(3D GRE) signal caused by intra-voxel dephasing. To minimize
these artifacts, care should be taken in order to preserve
the relevant information in the ACS data to properly compute
the GRAPPA kernels.},
cin = {AG Stöcker / AG Reuter},
ddc = {610},
cid = {I:(DE-2719)1013026 / I:(DE-2719)1040310},
pnm = {354 - Disease Prevention and Healthy Aging (POF4-354)},
pid = {G:(DE-HGF)POF4-354},
typ = {PUB:(DE-HGF)16},
doi = {10.1002/mrm.70127},
url = {https://pub.dzne.de/record/282540},
}