Add command to replace IntendedFor fields with B0FieldSource/B0FieldIdentifier

[tsalo]

SDCFlows doesn't seem to work on phase-difference field maps with the IntendedFor field, but it does work on B0FieldSource/B0FieldIdentifier fields. EPI distortion correction seems to work with either one.

I'm not sure how to correctly divvy up field maps if multiple ones are intended for the same distorted files.

Per Matt, check for shim settings.

[mattcieslak]

Just to double-check, which of the phasediff files had the IntendedFor in its sidecar? both the phasediff and the magnitude images?

[tsalo]

I just checked and it's actually a separate-phase maps setup, but the IntendedFor is present in all four files.

[mattcieslak]

This might be an sdcflows bug then

[tsalo]

@mattcieslak you're right. It looks like SDCFlows identifies B0Field* fmaps first, and it ignores the session entity when it does it, so having even one B0Field*-type fmap in the BIDS dataset will mean that IntendedFor ones won't be identified.

[tsalo]

Still, given that there's this weird limitation in SDCFlows, it would definitely be useful to have a command that ensures that we use consistent field map labeling in a dataset.

[tsalo]

Plus it would generally be a good idea to include tools to basically update BIDS datasets to use newer features. Here are a few examples:

• IntendedFor --> B0Field*
• Relative paths --> BIDS URIs
• rec-magnitude/phase from old versions of Heudiconv --> part-mag/phase
• Deprecated suffixes phase, FLASH, PD, and T2star