Материал: part17

The first input to the Volumetric Presentation State (VPS) Display Module provides the full (uncropped) MPR view of the anatomy in​ thedisplay,whichwillbeleftasgrayscaleintheVPSDisplayModule.Thiswillprovidethebackdroptothecolorizedsegmentedinputs​ to be subsequently overlaid by compositor components of the Volumetric Presentation State Display pipeline.​

The same input data and a single set of MPR geometry parameters defined in the Multi-Planar Reconstruction Geometry Module are​ used to generate each VPS Display Module input; only the cropping is different. The Volume Cropping Module for each of the other​ inputsspecifiestheincludedsegmentsusedtocropawayallpartsofthevolumewhichdonotbelongtoanoduleofthecorresponding​ nodule category.​

From these cropped volumes Planar MPR views are generated, which are then colorized and overlaid on the grayscale background​ within the Volume Presentation State Display Module (see Section FF.2.3.2.1 “Classification Component Components” in PS3.4).​

IntheVolumetricPresentationStateDisplayModulethePresentationStateClassificationComponentSequence(0070,1801)defines​ scalar-to-RGB transformations for mapping each MPR view to RGBA. The first MPR (anatomy) view is mapped to grayscale RGB​ by a RGB LUT Transfer Function (0028,140F) value of EQUAL_RGB. Alpha LUT Transfer Function (0028,1410) is set to NONE; i.e.,​ the anatomy will be rendered as completely opaque background.​

For each of the three lung nodule MPR views an RGB transfer function maps the view to the color corresponding the respective​ nodule category. Alpha is set to 0 for black pixels, making them completely transparent. Alpha for all other pixels is set to 1 (or a value​ between 0 and 1, if some of the underlying anatomy shall be visible through the nodule segmentation).​

Presentation State Compositor Component Sequence (0070,1805) in the Volumetric Presentation State Display Module then creates​ a chain of three RGB Compositor Components which composite the four MPR views into one. The first RGB Compositor performs​ "Partially Transparent A over B" compositing as described in Section XXX.5.2 by passing through the Alpha of input 2 as Weight-2​ and 1-Alpha of input 2 as Weight-1.​

The remaining two Compositor Components then perform "Pass Through" compositing as described by Section XXX.5.3 by using​ Weighting LUTs which simply pass through Alpha-1 as Weight-1 and Alpha-2 as Weight-2, since the output of the previous Compos-​ itor Components contains no Alpha, and therefore Alpha-1 will automatically be set to one minus Alpha-2 by the Compositor.​

Figure XXX.3.6-3 shows the complete pipeline for the lung nodule example:​

Figure XXX.3.6-3. Lung nodule example pipeline​

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It is envisioned that display applications provide user interfaces for manipulating the Alpha LUT Transfer Functions for each input of​ the pipeline, allowing the user to control the visibility of the highlighting of each lung nodule category.​

XXX.3.6.3 Encoding Details​

XXX.3.6.3.1 Volumetric Presentation State Relationship Module Recommendations​

Table XXX.3.6-1. Volumetric Presentation State Relationship Module Recommendations​

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XXX.3.6.3.2 Volumetric Presentation State Cropping Module Recommendations​

Table XXX.3.6-2. Volumetric Presentation State Cropping Module Recommendations​

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XXX.3.7 Ultrasound Color Flow MPR​

XXX.3.7.1 User Scenario​

Ultrasound images and volumes are able to depict both anatomic tissue information (usually shown as a grayscale image) along with​ functional tissue motion or blood flow information (usually shown in colors representing motion towards or away from the ultrasound​ transducer).​

The sample illustration in Figure XXX.3.7-1 is comprised of three Color Flow MPR presentations that are approximately mutually or-​ thogonalintheVPSReferenceCoordinateSystem.EachpresentationisdescribedbyonePlanarMPRVolumetricPresentationState​ instance, with layout and overlay graphics provided by a Hanging Protocol instance. The three VPS instances share the same value​ of Presentation Display Collection UID (0070,1101) indicating that they are intended to be displayed together.​

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Figure XXX.3.7-1. Planar MPR Views of an Ultrasound Color Flow Volume​

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)containsoneitemperframeoftheEnhancedUSVolumeinstance.SpatialRegistrationisnotnecessarysince​ bothframesetssharethesameVolumeFrameofReferenceinthesourceinstance.Croppingisusuallynotnecessaryformulti-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 compos-​ iting.​

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

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

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