C.11.17.1 Structured Display Image Box Attribute Descriptions

C.11.17.1.1 Display Environment Spatial Position

The Display Environment Spatial Position (0072,0108) specifies the corners of the Image Box relative to the vertical and horizontal dimensions of the Display Environment, specified as Number of Vertical Pixels (0072,0104) and Number of Horizontal Pixels (0072,0106) in the Nominal Screen Definition Sequence (0072,0102).

See also Section C.23.2.1.1.

Within the Image Box, the image (or the area of the image selected for display by the associated Presentation State SOP Instance) shall be scaled to fit the display area under the constraint that the aspect ratio of the image is maintained.

In rendering the Image Box, the Application Entity may render display controls (such as cine speed control, or stack position indication) either within or outside the specified Display Environment Spatial Position (0072,0108).

C.11.17.1.2 Referenced Image Sequence and Referenced Presentation State Sequence

Image SOP Instances, or frames from multi-frame SOP Instances, to be displayed in an Image Box may be identified either directly by the Referenced Image Sequence (0008,1140), or indirectly through the Referenced Presentation State Sequence (0008,9237).

Referenced Image Sequence (0008,1140) is permitted to be zero length, indicating an empty Image Box.

Note: 1. The recommended display color for an empty Image Box is specified by Empty Image Box CIELab Value (0072,0421).

2. When displaying a standard template such as a dental full mouth series, an empty image box may be used to indicate that the corresponding view was not taken.

If images are identified indirectly through the Referenced Presentation State Sequence (0008,9237), all of the image frames identified in the top level Referenced Series Sequence (0008,1115) attribute shall be displayed. For images identified indirectly through a Blending Presentation State SOP Instance, all the image frames for which the Blending Position (0070,0405) value is UNDERLYING shall be displayed, with the relevant SUPERIMPOSED images blended as necessary.

If images are to be displayed, the number of frames referenced for display shall be consistent with the value of Image Box Layout Type (0072,0304). If the value of Image Box Layout Type is SINGLE, only a single frame shall be referenced, either directly or indirectly; if the value is CINE, only a single multi-frame SOP Instance shall be referenced.

If the value of Image Box Layout Type is STACK, more than one SOP Instance or frame may be referenced, and the frames constitute a stack to be displayed in the Image Box. For frames identified by the Referenced Image Sequence, the order of stepping through the stack shall be the order of Image SOP Instance references in that Sequence. If multiple frames are selected in Referenced Frame Number (0008,1160), those frames shall be stepped through in the order of their listing in that attribute, within the order of display of their Image SOP Instance.

For a stack whose frames are selected indirectly through an Item of the Referenced Presentation State Sequence, the order of stepping through the stack shall be the order of SOP Instance references in the Referenced Series Sequence (0008,1115) of the referenced Presentation State. For a referenced Blending Softcopy Presentation State, this shall be the Referenced Series Sequence within the Blending Sequence (0070,0402) for which the Blending Position (0070,0405) value is UNDERLYING.

Notes: 1. Display of images using Blending Softcopy Presentation State must use indirect SOP Instance reference through the Referenced Presentation State Sequence (0008,9237) at the top level of Structured Display Image Box Sequence (0072,0422) Item, and cannot use the Referenced Presentation State Sequence within an item of the Referenced Image Sequence (0008,1140).

2. A Blending Presentation State that references a blending of a single underlying frame and a single superimposed frame may be associated with a SINGLE Image Box Layout.

3. A reference to a single display frame, either directly through Referenced Image Sequence or indirectly through Referenced Presentation State Sequence, may be associated with either a STACK or a CINE Image Box Layout as a degenerate case.

4. There is no requirement for the pixel matrix sizes of the images in the stack, or the image display area as selected by referenced Presentation State SOP Instances, to be identical, nor for the referenced images to be of the same SOP Class.

5. Referenced Presentation States are an initial presentation control. The rendering Application Entity might allow a user to interactively enable/disable graphic layers, or change the zoom, rotation, window width / window level, or other presentation controls. Any such Application Entity functionality is beyond the scope of the Standard.

C.11.17.1.3 Referenced Instance Sequence

The Referenced Instance Sequence (0008,114A) references a non-Image SOP Instance, e.g., a Structured Report, Waveform, or Encapsulated Document SOP Instance, to be displayed in the image box. For such object references, the value of Image Box Layout Type (0072,0304) shall be SINGLE, even if displaying the object will require scrolling or paging (e.g., a multi-page encapsulated document).

C.11.17.1.4 Referenced Stereometric Instance Sequence

The Referenced Stereometric Instance Sequence (0008,1134) references a Stereometric SOP Instance, whose Stereo Pairs Sequence (0022,0020) references image pairs to be displayed in the Image Box. The number of image pairs referenced for display shall be consistent with the value of Image Box Layout Type (0072,0304). If the value of Image Box Layout Type is SINGLE, only a single pair of frames shall be referenced by the Stereo Pairs Sequence in the referenced stereometric instance; if the value is CINE, only a single pair of multi-frame SOP Instances shall be referenced; if the value is STACK, one or more pairs may be referenced constituting a stack to be displayed in the Image Box, and the order of stepping through the stack shall be the order of Items in the Stereo Pairs Sequence. The manner in which a stereo pair is rendered is unspecified.

Notes: 1. While the Stereometric IOD allows reference to multiple pairs of multi-frame cine Instances, the CINE Image Box Layout does not support the display of more than one (a “stack” of cines).

2. Display of stereo pairs typically requires specialized hardware (e.g., polarizing filters and shutter glasses).

C.11.17.1.5 Type of Synchronization

Type of Synchronization (0072,0434) specifies the method for synchronizing the display of images in two or more Image Boxes linked through the Synchronized Image Box List (0072,0432).

  1. FRAME: Stepping of frames in one Image Box is synchronized by the stepping of an identical number of frames in the other Image Boxes.

  2. POSITION: Stepping of frames in one Image Box is synchronized by the stepping of frames in the other Image Boxes to effect an identical relative positional offset within the patient based coordinate system. This presumes that the referenced images includes Image Position (Patient) (0020,0032) and Image Orientation (Patient) (0020,0037) attributes, and that the stacks have approximately the same orientation relative to the patient based coordinate system.

  3. TIME: Playback of frames in one Image Box is synchronized by the playback of frames in the other Image Boxes to effect an identical temporal offset from the original displayed frame. This presumes that the referenced images include Frame Time (0018,1063), Frame Time Vector (0018,1065), or Frame Reference DateTime (0018,9151). It also presumes that if the Image Box Layout Type (0072,0304) is STACK, the frames are referenced in a monotonically increasing time order in the stack.

  4. PHASE: Playback of frames in one Image Box is synchronized by the playback of frames in the other Image Boxes to effect an identical phase offset. This presumes that the referenced frames within each referenced Image Box constitute a uniform sampling across a single “cycle”, and that relative position within that cycle is synchronized across all the referenced Image Boxes. For Image Boxes with Image Box Layout Type (0072,0304) value CINE, the set of frames to be displayed as one cycle may be specified either using the Referenced Frame Number (0008,1160) attribute within the Referenced Image Sequence (0008,1140), or if that attribute is not present, using the values of attributes Start Trim (0008,2142) and Stop Trim (0008,2143).

Notes: 1. PHASE may be used, for instance, to synchronize display of images representing a single cardiac cycle.

2. Synchronization of Image Boxes is an initial presentation control. The rendering Application Entity might allow a user to unlink the synchronization, e.g., to navigate to cine frames before the Start Trim (0008,2142) frame or after the Stop Trim (0008,2143) frame. Any such Application Entity functionality is beyond the scope of the Standard.