In our study in which we tested different sequence variants, I acquired single-volume EPIs.
Related to the naming of these files, I already got a very helpful suggestion Single volume EPI data that worked perfectly!
However, I did notice that I am getting the following errors from the BIDS validator which makes sense as I do only have one volume.
**[Code 54] BOLD_NOT_4D**
Bold scans must be 4 dimensional.
**[Code 75] NIFTI_PIXDIM4**
NIfTI file's header is missing time dimension information.
I do not know how I should rename these files as the sequence was identical to the resting-state sequence but these acquisitions consisted of a single volume.
It looks like you decided to use the bold suffix for good reasons, so I would just recommend adding a singleton fourth dimension to your one-volume BOLD files.
Actually, I was thinking that I already had the 4th dimension. When I check my hdr info using the commands from FSL (with fslinfo or fslhd), I see the following:
That does seem like it should be good. I don’t use FSL often, but I assume it doesn’t add empty dimensions to the header info. Is it possible that some of your files are 3D, while others are 4D? The validator should show a list of the files for which the BOLD_NOT_4D and NIFTI_PIXDIM4 errors were found.