It has previously been demonstrated that EPI acquisitions
with reversed phase-encode blip polarities can be used to correct image
distortions.A by-product of these
methods is a shift map that maps the two source images together.Here, we demonstrate that one of the
algorithms previously utilized for distortion correction purposes can be
modified to produce high-SNR volumetric field maps for shimming
purposes.These results suggest that
such methods could be used to collect spatially accurate volumetric field
maps for shimming purposes in a matter of seconds.
