Similar to a previous question I asked, my lab has a set of ABCD task-fmri and associated fieldmaps which contain multiple reverse-PE images that need to be manually split after
The fieldmaps consist of interleaved “blip-up” and “blip-down” spin-echo images which are used for SDC correction (i.e. through topup).
The first volume of each task-fMRI bold sequence is a gradient-echo sequence. It was explained to me that this is not used for B0/SDC correction (due to dropout in the image), however it is used to “check” the accuracy of the distortion field estimated from the spin-echo images.
Labeling the spin-echo images seems simple enough (i.e.
sub-01_dir-[AP/PA]_epi.nii.gz), however I am somewhat confused what I should do with the gradient echo images. Should I just discard these? Should I instead label the spin-echo maps as “magnitude1,2” and the gradient echo images as “phase1,2”?