Thanks @Steven!
To summarize, once I fixed the user path errors it did process the fieldmaps, but did not apply them because the _asl.json is missing the TotalReadoutTime. I did a quick test with a dummy readout time inserted and everything ran fine.
Now I just need to figure out the true Total Readout Time, which is easier said than done.
The data I am working with is not a Siemens product, but a custom 3D multi-delay pCASL that was made by Dr. Danny Wang’s group (as far as I am told). That is to say I don’t have the BandwidthPerPixelPhaseEncode or EffectiveEchoSpacing in the json, the dicoms, or the protocol pdf.
I did find this bit of useful info on how BPPFE is computed How is BandwidthPerPixelPhaseEncode calculated?, but I can’t seem to successfully replicate the TotalReadoutTIme in the fieldmap json, so I am not confident in doing this for _asl.json.
I will update this topic if/when I come to a solution, but for now I am just documenting for posterity’s sake.
Thanks again @Steven and @tsalo for helping me troubleshoot!
Best,
Jenya