Help deciphering DTI protocol names (what is AP or PA?)

I’m trying to create some heuristics to feed into heudiconv to have my dataset organized into BIDS. I’m planning to organize things into BIDS mostly off of the protocol_name, but I’m seeing some entries in that field that don’t make it obvious whether those scans should be in the same category.

I see 4 types of DTI scans. They are named one of: DTI_60slices_30dir_2mmiso REF AP, DTI_60slices_30dir_2mmiso REF PA, DTI b0 1 AP, DTI b0 2 PA

I’m guessing the former two should a filename like:

Whereas the latter two should have something like:

But for each of those two types, they could be separated further into which one has AP and which one has PA. I’m not sure what AP or PA means, does anyone know? And can these two types of scans be classified as the same scan (i.e. have the same filename format), or should they be distinct?

Update: I’ve found this thread: Getting data into BIDS format, which doesn’t directly answer my question but helps a bit. My goal now is to figure out which of the two types of scans (if either) include diffusion weighting. But I’m not sure if this makes sense because for both AP and PA, there is an acq-B0 scan…

In my previous workplace, AP usually means anterior-posterior direction. But I’m not sure exactly if it is the same here.

Thank you! Adding posterior anterior to my search queries actually lead me to a helpful thread that seems to be related to this (Getting data into BIDS format)