DICOM PS3.17 2019a - Explanatory Information

XXX.3.7.2 Encoding Outline

Each of the planar MPR presentations in the display is specified by one Planar MPR Volumetric Presentation State instance. The source volume in this case is stored in an Enhanced US Volume instance, which uses two sets of frames to construct the volume: one set contains tissue intensity frames and one set contains flow velocity frames. Each set of frames comprise one input to the VPS instance and is referenced in one item of Volumetric Presentation State Input Sequence (0070,1201), wherein the Referenced Image Sequence (0008,1140) contains one item per frame of the Enhanced US Volume instance. Spatial Registration is not necessary since both frame sets share the same Volume Frame of Reference in the source instance. Cropping is usually not necessary for multi-planar reconstruction, and both inputs use the same MPR geometry specification.

Classification of the two data types is accomplished using Pixel Presentation (0008,9205) of TRUE_COLOR and two items in Presentation State Classification Component Sequence (0070,1801). The tissue intensity MPR frame is classified using Component Type (0070,1802) of ONE_TO_RGBA and RGB LUT Transfer Function (0028,140F) of EQUAL_RGB to create a grayscale image, while the flow velocity MPR frame is colorized by using Component Type (0070,1802) of ONE_TO_RGBA and RGB LUT Transfer Function (0028,140F) of TABLE and mapping to colors in an RGB color lookup table. Both inputs use Alpha LUT Transfer Function (0028,1410) of IDENTITY so that the alpha represents the magnitude of the input value.

Compositing of the two classified data streams is accomplished using one RGB compositor component, specified by one item in Presentation State Compositor Component Sequence (0070,1805). The Weighting Transfer Function Sequence (0070,1806) is used to accomplish "Threshold Compositing" as described in Section XXX.5.4, a common method used for ultrasound color flow compositing.

Figure XXX.3.7-2 shows the complete pipeline for Ultrasound Color Flow Planar MPR.

Planar MPR VPS Pipeline for Ultrasound Color Flow

Figure XXX.3.7-2. Planar MPR VPS Pipeline for Ultrasound Color Flow

DICOM PS3.17 2019a - Explanatory Information