I am trying to set up a heuristics file for a study with field maps, but I'm still confused after looking through the heudiconv example files and relevant parts of the BIDS 1.0.1 specification paper. The study acquires a field map before each functional/dwi scan type (i.e., one for each of four tasks and one for the dwi). The field maps correspond to case 4 in the BIDS specification, with two maps with different phase encoding directions.
First, should I use the "acq" field to denote the scan type the field map corresponds to? E.g., sub-01_ses-01_acq-rest_dir-PA_run-01_epi.nii.gz instead of
Second, the different directions are showing up as separate runs. Is that expected? E.g.,
Finally, and most importantly, how exactly do I add the "IntendedFor" field to the json? Can I do it in the heuristics file?