GE Direct Fieldmaps - how to debug PE direction?

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Hi @neurolabusc and @jenncummings ,

Regarding point #2, it is hard to say without a better understanding of the pulse sequence used for B0 field mapping, as already pointed out.

I guess the “GE Direct Fieldmaps” refer to the sequence that outputs the fieldmap in Hz and a Magnitude image as in here https://github.com/mr-jaemin/ge-mri/blob/main/doc/B0_fieldmap.pdf.

We have seen a similar post not long ago:
fMRIPrep 20.2.3 directly measured B0 map SDC correction created worse functional images

Can it be solved with a similar solution (reorient or flip the sign of the fieldmap in some cases) ?

Thanks