DICOM PS3.3 2018a - Information Object Definitions

A.51.5 Segmentation Functional Groups
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### A.51.5 Segmentation Functional Groups

Table A.51-2 specifies the use of the Functional Group Macros used in the Multi-frame Functional Groups Module for the Segmentation IOD.

Table A.51-2. Segmentation Functional Group Macros

Functional Group Macro | Section | Usage
--- | --- | ---
Pixel Measures | C.7.6.16.2.1 | C - Required if Derivation Image Functional Group (C.7.6.16.2.6) is not present. May be present otherwise. See Section A.51.5.1
Plane Position (Patient) | C.7.6.16.2.3 | C - Required if Derivation Image Functional Group (C.7.6.16.2.6) is not present. May be present otherwise. See Section A.51.5.1
Plane Orientation (Patient) | C.7.6.16.2.4 | C - Required if Derivation Image Functional Group (C.7.6.16.2.6) is not present. May be present otherwise. See Section A.51.5.1
Derivation Image | C.7.6.16.2.6 | C - Required if any of Pixel Measures (C.7.6.16.2.1) or Plane Position (Patient) (C.7.6.16.2.3) or Plane Orientation (Patient) (C.7.6.16.2.4) Functional Groups are not present. May be present otherwise. See Section A.51.5.1
Frame Content | C.7.6.16.2.2 | M
Segmentation | C.8.20.3.1 | M

#### A.51.5.1 Segmentation Functional Groups Description

When a Frame of Reference UID is present the segment shall be specified within that coordinate system, using the Pixel Measures, Plane Position (Patient) and Plane Orientation (Patient) Functional Groups. Since this defines the spatial relationship of the segment, the size of the segmentation frames need not be the same size, or resolution, as the image data used to generate the segment data. The Derivation Image Functional Group may also be present, to specify on which images the segmentation was actually performed (since there may be others in the same Frame of Reference that are spatially co-located, but were not used to perform the segmentation).

If the Frame of Reference UID is not present, each pixel of the segmentation shall correspond to a pixel in a referenced image, using the Derivation Image Functional Group. Hence, the rows and columns of each referenced image will match the segmentation image. If both the Frame of Reference UID and the Derivation Image Functional Group are present, the segmentation and referenced image pixels need not correspond.

The value of Purpose of Reference Sequence (0040,A170) in the Derivation Image Functional Group Macro shall be (121322, DCM, "Source Image for Image Processing Operation"). The value of Derivation Code Sequence (0008,9215) shall be (113076, DCM, "Segmentation").

### Note

Non-image source instances used during segmentation, such as real world value maps, can be described in the top level data set in the Source Instance Sequence (0042,0013) of the General Reference Module and are implied to have been used for the derivation of all frames. I.e., there is no mechanism for selectively specifying on a per-frame basis which non-image instances were used. Real World Value Map instances already contain a means of selectively applying different scale factors to different frames.

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DICOM PS3.3 2018a - Information Object Definitions