The Segmentation IOD specifies a multi-frame image representing a classification of pixels in one or more referenced images. Segmentations are binary, fractional, or label map. If the referenced images have a defined Frame of Reference, the Segmentation Instance shall have the same Frame of Reference and is not required to have the same spatial sampling or extent as the referenced images. If the referenced image does not have a defined Frame of Reference, the Segmentation Instance shall have the same spatial sampling and extent as the referenced image.

The Segmentation IOD does not include the full set of acquisition parameters of the referenced images, e.g., cardiac phase. An application rendering or processing the Segmentation Instance may need to access the referenced images for such information.

The Segmentation IOD is used in two SOP Classes as defined in PS3.4 Storage Service Class, a SOP Class for storage of BINARY and FRACTIONAL segmentations, and a SOP Class for storage of LABELMAP segmentations. These are distinguished by their SOP Class UID and by the Enumerated Value of the Segmentation Type (0062,0001) of the Segmentation Image Module.