Fieldmaps in fmriPrep 20.2.7 and where to find them

Hello all,

For comparison reasons, I need to find the warps applied during susceptibility distortion correction (SDC) in fmriPrep 20.2.7 (LTS). I searched the documentation of both fmriPrep and sdcFlows but could not find a clear indication of what file contains the information about how much each voxel need to be shifted (i.e. the warp field, necessary for SDC).

Thank you in advance!

The SDC unwarping file is not output in fMRIPrep 20.2.x. One would need to dig through the working directory to find it. The easiest way to find it (since each fieldmap type would produce a different correction workflow) would be to look for a merge_xforms directory. There you’ll find a _report/report.rst file which will list the transform files that will be passed to antsApplyTransforms.