TY  - JOUR
AU  - Yarach, Uten
AU  - Luengviriya, Chaiya
AU  - Danishad, Appu
AU  - Stucht, Daniel
AU  - Godenschweger, Frank
AU  - Schulze, Peter
AU  - Speck, Oliver
TI  - Correction of gradient nonlinearity artifacts in prospective motion correction for 7T MRI.
JO  - Magnetic resonance in medicine
VL  - 73
IS  - 4
SN  - 0740-3194
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DZNE-2020-04168
SP  - 1562-1569
PY  - 2015
AB  - To demonstrate the effect of gradient nonlinearity and develop a method for correction of gradient nonlinearity artifacts in prospective motion correction (Mo-Co).Nonlinear gradients can induce geometric distortions in magnetic resonance imaging, leading to pixel shifts with errors of up to several millimeters, thereby interfering with precise localization of anatomical structures. Prospective Mo-Co has been extended by conventional gradient warp correction applied to individual phase encoding steps/groups during the reconstruction. The gradient-related displacements are approximated using spherical harmonic functions. In addition, the combination of this method with a retrospective correction of the changes in the coil sensitivity profiles relative to the object (augmented sensitivity encoding (SENSE) reconstruction) was evaluated in simulation and experimental data.Prospective Mo-Co under gradient fields and coils sensitivity inconsistencies results in residual blurring, spatial distortion, and coil sensitivity mismatch artifacts. These errors can be considerably mitigated by the proposed method. High image quality with very little remaining artifacts was achieved after a few iterations. The relative image errors decreased from 25.7
KW  - Algorithms
KW  - Artifacts
KW  - Image Enhancement: methods
KW  - Image Interpretation, Computer-Assisted: methods
KW  - Imaging, Three-Dimensional: methods
KW  - Magnetic Resonance Imaging: instrumentation
KW  - Magnetic Resonance Imaging: methods
KW  - Motion
KW  - Nonlinear Dynamics
KW  - Phantoms, Imaging
KW  - Reproducibility of Results
KW  - Sensitivity and Specificity
LB  - PUB:(DE-HGF)16
C6  - pmid:24798889
C2  - pmc:PMC4221571
DO  - DOI:10.1002/mrm.25283
UR  - https://pub.dzne.de/record/137846
ER  -