Since version 21.0, BrainVoyager supports the “Brain Imaging Data Structure” (BIDS) recommendation, which is “a simple and intuitive way to organize and describe your neuroimaging and behavioural data” (see BIDS website). The recommended organization of the data places session folders (named "ses-<session-name>") under subject folders (named "sub-<suject-name>"), which are located themselves under a top-level project folder. The session and suject names are usually integral numbers, e.g. "sub-07", "ses-02" but can also be text labels. The data within a session is further distributed in sub-folders according to their MRI data (scan) type. For example, the anat folder contains anatomical data, while the func folder contains the functional data of all runs of a session. The folder structure is partially also reflected in the BIDS file naming convention, i.e. files usually contain the subject name, session name, type of scan as well as the run number for functional data (see example folder and file naming below). For more details, consult the complete BIDS specification.
As indicated by the BIDS compatible flag (see rectangle in screenshot above), the Data Analysis Manager creates files and folders in BIDS format automatically when creating documents from raw DICOM files (see example folder structure below). This includes creation of NIfTI files together with sidecar files that contain useful information not stored in NIfTI files; furthermore, the created files are organized inside a project folder according to the BIDS specification.
The example folder structure above shows the resulting data organization for subject "01" when running the data analysis manager's create project workflow in BIDS mode. The anat folder contains the 3D anatomical data recorded in session "01" in a compressed NIfTI file ("sub-01_ses-01_T1w.nii.gz") and a JSON sidecar file with the same name ("sub-01_ses-01_T1w.json") containing DICOM related information as well as BrainVoyager-specific information. The dwi folder (not shown in screenshot above) will contain documents created from diffusion MRI (DICOM) data. The func folder contains the 4D functional data of run "01" recorded in session "01" in a compressed NIfTI file ("sub-01_ses-01_task-images_run-01_bold.nii.gz"). Besides replicating the subject andd session name, the NIfTI file also contains a "task-" substring with a short name for the task of the fMRI run ("images"). In addition to the data file, a JSON file with the same name is also stored in the "func" folder containing DICOM related information as well as BrainVoyager specific information about the temporal scanning parameters. Since in this example a BrainVoyager project file was provided when converting the DICOM data to BIDS NIfTI files, the JSON file will also contain the protocol information describing the events/blocks constituting the task-based fMRI study. According to the BIDS recommendation, such protocol information should be available in a tab-separated value (TSV) file, which is also generated by the data analysis manager if a protocol file is available and stored under the same name except that the last file name component is changed from "bold" to "events" ("sub-01_ses-01_task-images_run-01_events.tsv").
Note. In case that a protocol was not (yet) availale when converting from DICOM to NIfTI in BIDS mode, it is possible to convert a protocol at any time using the Save PRT as TSV button in the Save protocol as BIDS-compatible TSV file field of the Protocol Options dialog. The resulting file should then be named as required by BIDS and saved in the func folder of the respective subject(s).
In case NIfTI files are already available, one can (since version 22.0) import them into a created porject using the Import NIfTI Document Workflow.
Copyright © 2020 Rainer Goebel. All rights reserved.