I'm running FsFastPreProc on a dataset with a number of subjects, where each subject has two sessions.

There's a separate structural image taken in each session. I want to make sure each subject's functional data is registered to the correct structural image. When running fsfast, setting up the file structure I can see clearly how FsFast uses the subjectname file to identify the right subject. It also seems easy enough to register multiple T1 images - just include multiple inputs for each subject to the recon-all command. 

But how do I map the session to the appropriate T1 image in the structural data?

Also, if I were registering feat directories to structural using reg-feat2anat - how would I specify the session in that case?

Does this even matter? Perhaps FSFastPreProc is built to process images without having a T1 from the same session as each image.

If there's not an easy way to do this, would a suitable workaround be to create a separate anatomical subject folder for every subject*session?

Thanks very much for your help!

Best regards

Ben