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Abdominal Water/Fat Separated MR Fingerprinting on a Lower-Field 0.75T MRI
Christian Guenthner1, Peter Koken2, Peter Boernert2,3, and Sebastian Kozerke1
1University and ETH Zurich, Zurich, Switzerland, 2Philips Research, Hamburg, Germany, 3Leiden University Medical Center, Leiden, Netherlands
The feasibility of concurrent water/fat separation and T1/T2 mapping using FISP-MR Fingerprinting was assessed on a lower-field 0.75T MRI.
Figure 4: (A) Reference cartesian Dixon scan and (B) water/fat resolved MRF. Abdominal water/fat separated FISP-MRF results show proton density and T1/T2 parameter maps for both fat and water separately. A mask was applied to the parameter maps to only show regions of sufficient proton signal. The proton density images compare well between MRF and the classical Dixon sequence, with inflow effects being present in the MRF scan leading to bright vessels.
Figure 1: FISP-MRF sequence with interleaved in- and out-of-phase echo times for water/fat separation at 0.75T. For each flip angle, an out-of-phase image is acquired first with an echo time of 4.6 ms followed by an in-phase image with 9.21 ms echo time (N.B.: the water/fat shift at 0.75T is approximately 108 Hz). For acquisition, a 12 ms Archimedean spiral readout with 7 interleaves and 2mm nominal resolution was used. For each time point only one spiral interleave was acquired, leading to a 7-fold undersampled acquisition