Comparison of navigator echo and centroid corrections of image displacement induced by static magnetic field drift on echo planar functional MRI.

Image displacement caused by static magnetic field drift may result in serious edge artifacts in echo-planar functional magnetic resonance imaging (MRI). We compared navigator echo and centroid methods for correcting the artifacts for phantom and in vivo studies. A motor-stimulation fMRI study was performed to demonstrate the possible effects due to the displacement. The navigator echo method was shown to be the superior technique for the correction of image displacement by effectively eliminating edge artifacts, resulting in improved functional maps.