Hello BIDS-experts,
I run a two-session MRI study and, of course, I am converting my data to BIDS.
I have a bunch of data about the participants for each session that I would like to include, e.g., what time of time day they were scanned, who scanned them, temperature, etc. but I am not quite sure where to best include it.
First, I thought about adding columns to the participants.tsv file but I didn’t like the idea that I would need separate columns for each session, e.g., temperature_ses-01 and temperature_ses-02 since I generally prefer the long table format, so something like:
| participant_id | session | temperature_celcius |
|---|---|---|
| sub-01 | ses-01 | 21.5 |
| sub-01 | ses-02 | 22.0 |
| sub-02 | ses-01 | 20.9 |
| … | … | … |
But, according to the relevant section in the BIDS specification …
Each participant MUST be described by one and only one row.
So I MUST do something like this:
| participant_id | session | temperature_s1 | temperature_s2 |
|---|---|---|---|
| sub-01 | ses-01 | 21.5 | 22.0 |
| … | … | … | … |
Of course, this is not the end of the world, but I still wondered if anyone could recommend another option. For example, I thought about creating additional behavioral data files where I would have more freedom to choose the data organization. Then again, the data I want to document here are not really an additional behavioral experiment, so maybe that’s not ideal either.
I only have two sessions here, so even a wide format (as shown above) would not hurt, but for longitudinal datasets this seems even more relevant, so maybe someone has figured out a good solution.
Thanks in advance and best,
Lennart