Материал: part17

Sets of temporally-related volumes may have been acquired sequentially or acquired asynchronously and reassembled into a tem-​ poral sequence, such as through Spatial-Temporal Image Correlation (STIC). Regardless of how the temporal volume sequence was​ acquired,framesintheresultantvolumesaremarkedwithatemporalpositionvalue,suchasTemporalPositionTimeOffset(0020,930D)​ indicating the temporal position of the resultant volumes independent of the time sequence of the acquisition prior to reassembly into​ volumes.​

PP.3.2 2D Derived Images​

The 2D image types represent collections of frames that are related to or derived from the volume data, namely Render Views (pro-​ jections), separate Multi-Planar Reconstruction (MPR) views, or sets of spatially-related source frames, either parallel or oblique (the​ cross-hatched images in Figure PP.3-1). The Ultrasound Image and Ultrasound Multi-frame Image IODs are used to represent these​ related or derived 2D images. The US Image Module for the Ultrasound Image Storage and Ultrasound Multi-frame Image Storage​ SOP Classes have defined terms for "3D Rendering" (render or MPR views) and "Spatially Related Frames" in value 4 of the Image​ Type (0008,0008) Attribute to specify that the object contains these views while maintaining backwards compatibility with Ultrasound​ review applications for frame-by-frame display, which may be displayed sequentially ("fly-through" or temporal) loop display or as a​ side-by-side ("light-box") display of spatially-related slices. Also, the optional Source Image Sequence (0008,2112) and Derivation​ Code Sequence (0008,9215) Attributes may be included to more succinctly specify the type of image contained in the instance and​ the 3D Volume Data set from which it was derived.​

2D Derived image instances should be linked to the source 3D Volume Data set through established DICOM reference mechanisms.​ This is necessary to support the "Two-Stage Review" use case. Consider the following examples:​

1.​In the case of a 3D Volume Data set created from a set of spatially-related frames within the ultrasound scanner,​

•​the Enhanced US Volume instance should include​

a.​Referenced Image Sequence (0008,1140) to the source Ultrasound Image and/or Multi-frame Image instances​

b.​Referenced Image Purpose of Reference Code Sequence (0040,A170) using (121346, DCM, "Acquisition frames corres-​ ponding to volume")​

•​and the Ultrasound Image and/or Multi-frame Image instances should include:​

a.​Referenced Image Sequence (0008,1140) to the 3D Volume Data set​

b.​Referenced Image Purpose of Reference Code Sequence (0040,A170) using (121347, DCM, "Volume corresponding to​ spatially-related acquisition frames")​

2.​In the case of an Ultrasound Image or Ultrasound Multi-frame Image instance containing one or more of the spatially-related​ frames derived from a 3D volume data, the ultrasound image instance should include:​

a.​Source Image Sequence (0008,2112) referencing the Enhanced US Volume instance​

b.​Source Image Sequence Purpose of Reference Code Sequence (0040,A170) using (121322, DCM, "Source of Image Pro-​ cessing Operation")​

c.​Derivation Code Sequence (0008,9215) using (113091, DCM, "Spatially-related frames extracted from the volume")​

3.​In the case of separate MPR or 3D rendered views derived from a 3D Volume Data set, the image instance(s) should include:​

a.​Source Image Sequence (0008,2112) referencing the Enhanced US Volume instance​

b.​Source Image Sequence Purpose of Reference Code Sequence (0040,A170) using (121322, DCM, "Source of Image Pro-​ cessing Operation")​

c.​Derivation Code Sequence (0008,9215) using CID 7203 “Image Derivation” code(s) describing the specific derivation oper-​ ation(s)​

PP.3.3 Physiological Waveforms Associated With 3D Volume Data sets​

ECGorotherphysiologicalwaveformsassociatedwithanEnhancedUSVolume(item1dintheusecasehierarchy)aretobeconveyed​ via a one or more companion instances of Waveform IODs linked bidirectionally to the Enhanced US Volume instance. Physiological​

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waveforms associated with Ultrasound image acquisition may be represented using any of the Waveform IODs, and are linked with​ the Enhanced US Volume instance and to other simultaneous waveforms through the Referenced Instance Sequence in the image​ instance and each waveform instance. The Synchronization module and the Acquisition DateTime Attribute (0018,1800) are used to​ synchronize the waveforms with the image and each other.​

PP.3.4 Workflow Considerations​

The use case of two-step review (item 2a in the use case hierarchy) is addressed by the use of separate SOP Classes for 2D and​ 3D data representations. A review may initially be performed on the Ultrasound Image and Ultrasound Multi-frame Image instances​ created during the study. If additional operations on the 3D volume data are desired, the Enhanced US Volume instance referenced​ in the Source Image Sequence of the derived object may be individually retrieved and operated upon by an appropriate application.​

The 3D volume data spatially relates individual frames of the image to each other using the Transducer Frame of Reference defined​ in Section C.8.24.2 in PS3.3 (items 2b in the use case hierarchy). This permits alignment of frames with each other in the common​ situation where a hand-held ultrasound transducer is used without an external frame of reference. However, the Transducer Frame​ ofReferencemayinturnberelatedtoanexternalFrameofReferencethroughtheTransducerGantryPositionandTransducerGantry​ Orientation Attributes. This would permit the creation of optional Image Position and Orientation values relative to the Patient when​ this information is available. In addition to these frames of reference, the spatial registration, fiducials, segmentation, and deformation​ objects available for other Enhanced objects may also be used with the Enhanced US Volume instances.​

TheKeyObjectSelectionDocumentSOPClassmaybeusedtoidentifyspecificEnhancedUSVolumeinstancesofparticularinterest​ (item 2d in the use case hierarchy).​

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QQ Enhanced US Data Type Blending​

Examples (Informative)​

QQ.1 Enhanced US Volume Use of the Blending and Display Pipeline​

This Annex contains a number of examples illustrating Ultrasound's use of the Blending and Display Pipeline. An overview of the​ examples included is found in Table QQ.1-1.​

Table QQ.1-1. Enhanced US Data Type Blending Examples (Informative)​

In the examples below, the following Attributes are referenced:​

•​Data Type (0018,9808)​

•​Data Path Assignment (0028,1402)​

•​Bits Mapped to Color Lookup Table (0028,1403)​

•​Blending LUT 1 Transfer Function (0028,1405)​

•​Blending LUT 2 Transfer Function (0028,140D)​

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•​Blending Weight Constant (0028,1406)​ •​RGB LUT Transfer Function (0028,140F)​ •​Alpha LUT Transfer Function (0028,1410)​

•​Red Palette Color Lookup Table Descriptor (0028,1101)​ •​Red Palette Color Lookup Table Data (0028,1201)​ •​Green Palette Color Lookup Table Descriptor (0028,1102)​ •​Green Palette Color Lookup Table Data (0028,1202)​ •​Blue Palette Color Lookup Table Descriptor (0028,1103)​ •​Blue Palette Color Lookup Table Data (0028,1203)​ •​Alpha Palette Color Lookup Table Descriptor (0028,1104)​ •​Alpha Palette Color Lookup Table Data (0028,1204)​

QQ.1.1 Example 1 - Grayscale P-Values Output​

Grayscale pass through for 1 data frame using identity Presentation LUT:​

Figure QQ.1-1. Example 1​

QQ.1.2 Example 2 - Grayscale-only Color Output​

Grayscale mapping only from 1 data frame:​

•​Weight 1:​

•​Blending LUT 1 Transfer Function = CONSTANT​

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