Image Viewer > Advanced Viewing

The Workstation can save image markup in a DICOM compliant format using Key Object Documents (KO in DICOM) and Softcopy Presentation States (PR in DICOM).

How Does it Work?

It is useful to have a basic understanding of what is going on behind the scenes. The following is a brief description of the KO and PR DICOM objects.

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The Key Object Document, at least in the context of key images, is simply the container for all the Softcopy Presentation States, which store all the markup, window/level, spatial transformations, etc, so that the images can be recalled looking the same as they did when the key images were saved. In DICOM, "key objects" actually covers a lot more than just "key images", but the information in this section will focus only on key images.

•	Each individual KO object (a DICOM file) must belong to, and be the only object in, a DICOM series.

•	Many Softcopy Presentation State objects (also just DICOM files) can be part of the same series, or different series within a study.

•	The KO essentially references all the PRs, which in turn contain all the presentation state information (e.g. the markup the user saved) for the images.

•	The PR objects just reference the original image(s) and store the information that tells the Workstation how to present the images to the user when recalled. At no point are the images themselves ever duplicated!

So, to put it very simply, each KO object will essentially boil down to a series of images in the Workstation. Consequently, they will appear in the right-click menu as shown below. The Workstation simply pieces together all the information from the KO and PR objects to reconstruct the key images to look the same as they did when they were initially created.