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