Containers
Data in Flywheel is organized in the following hierarchy of containers:
| Project | An experiment or other collection of subject data. Usually where the protocol for the experiment stays relatively constant. |
| Subject |
A project-specific research subject. |
| Session | A subject’s visit or exam performed for the project. (e.g. a single time in the MRI scanner for a subject) |
| Acquisition | Unit of data collected during a session. (e.g. a T1-MPRAGE sequence or one fMRI task) |
Data
Each Project hierarchy node instance (Project, Subject, Session, Acquisition) is a container for research data. Research data typically falls into the categories of files or metadata.
Files
Computer files uploaded by device connectors, Gears, or users. Examples would be zipped archives of DICOM files, nifti images produced by gears, or PDFs of the study protocol uploaded by the research coordinator.
Metadata
User defined key-value attributes that describe the Project, Subject, Session, Acquisition, File, or Analyses. This metadata may be generated by device connectors, Gears, or users. Examples would be Subject Age, timestamp of the acquisition start time, the Flywheel user that uploaded the file.