Benedikt Andreas Poser1,2, Peter J. Koopmans2, Lawrence L. Wald3, Markus Barth1,2
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; 2Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 3Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
A 3D-EPI sequence was implemented and its use investigated for high-resolution fMRI at 7T. Comparisons with conventional 2D-EPI reveal considerably increased sensitivity for isotropic 2.5mm resolutions and higher. Results of a whole-brain activation study at 1mm3 resolution at TR=3s are presented. The ability to apply parallel acceleration along two dimensions allows substantial time savings and protocols with >100 slices to remain compatible with fast fMRI. The SAR and gradient limitations or 2D-EPI are removed entirely, and the often compromised parallel reconstruction of 2D-EPI in regions of low SNR considerably improved. The results strongly suggest that 3D-EPI should be chosen over 2D at high field.
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