Pl Erik Goa1,2, Benedikt Andreas Poser2,3,
Markus Barth2,3
1Department of Medical
Imaging, St.Olav University Hospital, Trondheim, Norway; 2Erwin L.
Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen,
Essen, Germany; 3Donders Institute for Brain, Cognition &
Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands
Navigator phase correction is used in GRE sequences to remove respiration induced global phase variations. Non-balanced Steady-state free precession might also benefit from phase correction. Here we investigate the phase variation in S1 and S2 signals individually and evaluate two different navigator methods. Results show that the S2 phase is different from S1 phase and cannot be corrected using a single S1 navigator. An interleaved scheme where navigator echoes for both S1 and S2 are sampled every m TR will successfully correct both signals individually. BOLD-fMRI experiments on 7T shows significant increase in number of activated voxels using the interleaved scheme.
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