I definitely struggled for a while figuring out how to appropriately acquire
phase and magnitude images on our 3T GE HDx. Anyways, we just upgraded today
to the v. 15 M4 software, but were running v. 14. You definitely need to use
the CV to turn off ASSET when acquiring the gradient images. I think you
have a different CV than we do, we use opphasset_factor = 1. As for the
nograd option, I had always turned that on, but it has been suggested that
since the EPI images have gradient wrapping, this option should not be changed.
Hope this helps,