I’ve generally viewed the _run-
label as an optional field except for func
acquisitions. I realize that the BIDS specification contains this important line regarding runs
If several scans of the same modality are acquired they MUST be indexed with the
run-<index>
key-value pair:_run-1
,_run-2
,_run-3
, and so on (only nonnegative integers are allowed as run labels).
which leads me to a couple case-scenario questions:
1). If I were to collect two separate anat/T1w
acquisitions, but the parameters were different and noted in the _acq-
, _desc-
, _ce-
, or some other label, would the run label still be necessary for these two?
2). If I collect four dwi/dwi
acquisitions (two AP, two PA), do the run numbers need to go 01-04, or is this appropriate:
sub_01_dir-AP_run-01_dwi.nii.gz
sub_01_dir-PA_run-01_dwi.nii.gz
sub_01_dir-AP_run-02_dwi.nii.gz
sub_01_dir-PA_run-02_dwi.nii.gz
My impression is that BIDS doesn’t particularly care, but I’m curious if there’s some preferred method?
Thank!