Subtraction Item ID Attribute
| Tag | (0028,9416) |
|---|---|
| Type | Conditionally Required (1C) |
| Keyword | SubtractionItemID |
| Value Multiplicity | 1 |
| Value Representation | Unsigned Short (US) |
Identification of the Subtraction Item used to associate a certain Mask Sub-Pixel Shift (0028,6114) in the Frame Pixel Shift Functional Group.
See Section C.7.6.16.2.14.1.
Required if SOP Class UID (0008,0016) equals "1.2.840.10008.5.1.4.1.1.12.1.1" or "1.2.840.10008.5.1.4.1.1.12.2.1". May be present otherwise.
Section C.7.6.16.2.14.1
C.7.6.16.2.14.1 Subtraction Item ID Description
Subtraction Item ID (0028,9416) specifies the ID of a subtraction operation to which the Mask Sub-pixel Shift (0028,6114) is associated. The Subtraction Item ID is also present in the Mask Subtraction Sequence (0028,6100) to allow this association.
When used as per-frame Macro, the Subtraction Item ID (0028,9416) allows to specify different values of Mask Sub-pixel Shift (0028,6114) individually frame by frame, and relate them to a single Item of the Mask Subtraction Sequence (0028,6100).
Note
There is no restriction in the number of Subtraction Item ID's associated to each contrast frame. The same contrast frame may be present in several Items of the Mask Subtraction Sequence, each Item having a different value of Subtraction Item ID.
When used as shared Macro, the Subtraction Item ID (0028,9416) allows to specify one or more values of Mask Sub-pixel Shift that will be applied to all the frames of the Multi-frame image.
Note
Example of usage of Subtraction Item ID in a per-frame Macro, see Figure C.7.6.16-8:
In this example of Multi-frame Image with 3 frames, one Mask Frame (i.e., Frame 1) is applied to the next two frames of the Multi-frame image (i.e., Frames 2 and 3). Therefore, there is only one Item in the Mask Subtraction Sequence, containing its own Subtraction Item ID value (i.e., 100). The Frame Pixel Shift Macro allows to define a Mask Sub-Pixel Shift different for each contrast frame.
First Frame Subtracted: Subtraction of Frame 1 (Mask) to Frame 2, with Sub-Pixel Shift 1.3\2.4
Second Frame Subtracted: Subtraction of Frame 1 (Mask) to Frame 3, with Sub-Pixel Shift 1.9\3.0
Figure C.7.6.16-8. Example of usage of Subtraction Item ID in a per-frame Macro