diff --git a/src/longitudinal-and-multi-site-studies.md b/src/longitudinal-and-multi-site-studies.md index bf9cb92eec..b64ae016e8 100644 --- a/src/longitudinal-and-multi-site-studies.md +++ b/src/longitudinal-and-multi-site-studies.md @@ -80,7 +80,7 @@ for practical guidance when curating a new longitudinal dataset. This version of the BIDS specification does not explicitly cover studies with data coming from multiple sites or multiple centers (such extension is planned -in [BIDS `2.0`](https://github.com/bids-standard/bids-2-devel). +in [BIDS `2.0`](https://github.com/bids-standard/bids-2-devel/issues/11)). There are however ways to model your data without any loss in terms of metadata. ### Option 1: Treat each site/center as a separate dataset @@ -92,11 +92,21 @@ Apps and everything should just work. ### Option 2: Combining sites/centers into one dataset -Alternatively you can combine data from all sites into one dataset. To identify -which site each subjects comes from you can add a `site` column in the +Alternatively you can combine data from all sites into one dataset. +This can be done in two ways: + + +#### Option 2.a: Collate sites at subject level + +To identify which site each subjects comes from you can add a `site` column in the `participants.tsv` file indicating the source site. This solution allows you to -analyze all of the subjects together in one dataset. One caveat is that subjects +analyze all subjects together in one dataset. One caveat is that subjects from all sites will have to have unique labels. To enforce that and improve readability you can use a subject label prefix identifying the site. For example `sub-NUY001`, `sub-MIT002`, `sub-MPG002` and so on. Remember that hyphens and underscores are not allowed in subject labels. + +#### Option 2.b: Use different sessions for different sites + +In case of studies such as "Traveling Human Phantom" it is possible to incorporate site within session label. +For example `sub-human1/ses-NUY`, `sub-human1/ses-MIT`, `sub-phantom1/ses-NUY`, `sub-phantom1/ses-MIT` and so on.