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How XNAT stores data§

Imaging data§

Your imaging source files are stored as scans within an XNAT session. Your XNAT project will normally contain a session for each image acquisition.

Scans can contain any type of imaging file, although XNAT provides the most support for DICOM. If working with non-DICOM images, you may need to do some additional work in creating your uploading processes.

Processed image data§

In addition to Scans, you can store Reconstructions and Assessors in your XNAT sessions. These typically store the outputs of data processing operations which derive from the source data in the Scan.

Reconstructions are usually the image outputs of simple preprocessing operations on the source data, whereas Assessors could contain statistical or other outputs of more sophisticated processing algorithms. See Understanding the XNAT Data Model for more information.

Automated processing workflows typically use Dax or the XNAT Container Service to run processing on data uploaded to your project. If the processing has already been performed, you can use the XNAT REST API to upload reconstructions and assessors to your existing sessions.

  • See Data processing for more information about data processing workflows.

Non-imaging files§

Non-imaging files can be stored on XNAT as Resources. A Resource is essentially a folder you can attach to a session to store one or more non-imaging files relating to that session. You can also attach resource folders directly to individual subjects or to your project.

There are several ways to add resource files:

  • If you or your project members will be regularly uploading non-imaging files, you should consider creating a custom resource uploader to simplify the process of uploading these as resources.
  • If you want to add resources as a one-off, you can upload resource files manually using the Manage Files feature in the XNAT interface. See Uploading Data for more details.
  • You can also use the XNAT REST API to create and upload resource files as part of a custom uploading process.

Subject and session metadata§

XNAT stores metadata for each subject and session. You can modify this data and add your own custom fields. See Subject and session metadata for more information.