Reducing Ghosting in EPI Using Trajectory Based Reconstruction with Dixon Method Fat Suppressed Navigator Echoes at 7T

Oliver Josephs¹, Chloe Hutton¹, Joerg Stadler², Johannes Bernarding³, Oliver Speck³, Nikolaus Weiskopf¹

At 7T, navigator echoes, acquired at short TE, and used in EPI to reduce Nyquist ghosting, can be significantly compromised by fat signal. Usually, in EPI, fat is suppressed by applying a fat saturation pulse before slice selective excitation but at 7T this significantly increases the required SAR. We present a two point Dixon technique for suppressing the fat signal in the navigator echoes and demonstrate its effectiveness in human brain imaging. The new technique is an efficient alternative for improving phase navigators and can be used in additon to fat saturation and other artifact suppression methods.