TY  - JOUR
AU  - Tkotz, Katharina
AU  - Liebert, Andrzej
AU  - Gast, Lena V
AU  - Zeiger, Paula
AU  - Uder, Michael
AU  - Zaiss, Moritz
AU  - Nagel, Armin
TI  - Multi-echo-based fat artifact correction for CEST MRI at 7 T.
JO  - Magnetic resonance in medicine
VL  - 91
IS  - 2
SN  - 1522-2594
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DKFZ-2023-01968
SP  - 481-496
PY  - 2024
N1  - #LA:E020# / 2024 Feb;91(2):481-496
AB  - CEST MRI is influenced by fat signal, which can reduce the apparent CEST contrast or lead to pseudo-CEST effects. Our goal was to develop a fat artifact correction based on multi-echo fat-water separation that functions stably for 7 T knee MRI data.Our proposed algorithm utilizes the full complex data and a phase demodulation with an off-resonance map estimation based on the Z-spectra prior to fat-water separation to achieve stable fat artifact correction. Our method was validated and compared to multi-echo-based methods originally proposed for 3 T by Bloch-McConnell simulations and phantom measurements. Moreover, the method was applied to in vivo 7 T knee MRI examinations and compared to Gaussian fat saturation and a published single-echo Z-spectrum-based fat artifact correction method.Phase demodulation prior to fat-water separation reduced the occurrence of fat-water swaps. Utilizing the complex signal data led to more stable correction results than working with magnitude data, as was proposed for 3 T. Our approach reduced pseudo-nuclear Overhauser effects compared to the other correction methods. Thus, the mean asymmetry contrast at 3.5 ppm in cartilage over five volunteers increased from -9.2
KW  - 7 T (Other)
KW  - CEST (Other)
KW  - fat artifact (Other)
KW  - fat-water separation (Other)
KW  - knee imaging (Other)
KW  - nuclear Overhauser effect (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:37753844
DO  - DOI:10.1002/mrm.29863
UR  - https://inrepo02.dkfz.de/record/283203
ER  -