Forgive this horribly beginner question.
I have just collected my first field maps to use for distortion correction from a GE Discovery MR750. These are 2 pepolar scans.

Does running dcm2niix on pepolar scans create field maps that can then be used in preprocessing streams such as FMRIPREP? In other words, if I run
is this call that needs to be done to create a field map that can be used for distortion correction? Are other flags required (I did not see any in the help) or is further processing needed after running this command?
I'm mostly asking because I'm not exactly sure what to look for to guarantee the created .json and .nii files are, in fact correct. For example, I used the above command on 2 pepolar scans and the ensuing .json files indicated the same phase encoding axis (j), which I thought would be different between the two scans. However I'm not sure if this is the right place to look.


Thanks for any help on how to deal with pepolar scans.
Lauren