Dataset with 3 sessions and 2 subsessions in each session


I have a question regarding BIDS structure and I can’t find it on BIDS dedicated website.
I have a dataset where participants come 3 times to the scanner, and each time they’re scanned 2 times: pre and post stimulation. Is it possible to create anotehr session level (it’s not exactly a run either) or should I create 6 sessions?

For now I’m trying folders ses-T1pre, ses-T1post, ses-T2pre, ses-T2post and so on.

Or is it better to create 3 folders for each session and then specifz different measurements as _acq-<label>

Session is a logical grouping appropriate to your study and how you want to communicate it.

Session - a logical grouping of neuroimaging and behavioral data consistent across subjects. Session can (but doesn’t have to) be synonymous to a visit in a longitudinal study. In general, subjects will stay in the scanner during one session. However, for example, if a subject has to leave the scanner room and then be re-positioned on the scanner bed, the set of MRI acquisitions will still be considered as a session and match sessions acquired in other subjects. Similarly, in situations where different data types are obtained over several visits (for example fMRI on one day followed by DWI the day after) those can be grouped in one session. Defining multiple sessions is appropriate when several identical or similar data acquisitions are planned and performed on all -or most- subjects, often in the case of some intervention between sessions (for example, training). In the PET context, a session may also indicate a group of related scans, taken in one or more visits.

This seems reasonable.

This also seems reasonable.