Image objects of different types may be created from a 3D Ultrasound image acquisition, illustrated in Figure A.59-1. It can be seen that there are two different types of data related to 3D image acquisition: 3D volume datasets and several kinds of 2D image derived from the volume dataset.
Figure A.59-1: Types of 3D Ultrasound Source and Derived Images (Informative)
The 3D volume dataset (the diagonally shaded box in Figure A.59-1) contains a Cartesian volume or two or more temporally related Cartesian volumes. 3D volume datasets are exchanged using the Enhanced US Volume SOP Class, and are suitable for subsequent Multi-Planar Reconstruction and rendering operations. Within each Enhanced US Volume instance, each Cartesian volume consists of a set of parallel planes, and each plane consists of one or more frames each of a single data type. All Cartesian volumes have the same spacing between adjacent planes.
Most acquisition devices construct the Cartesian volume by resampling data from a different acquisition geometry. The method of generation of the Cartesian volume, its relationship to spatially-related 2D frames (whether the volume was created from spatially-related frames, or spatially-related frames extracted from the Cartesian volume), and the algorithms used for Multi-Planar Reconstruction and rendering operations are outside the scope of this standard.
The 2D image types represent collections of frames that are derived from the volume dataset, namely 3D rendered views (projections), separate Multi-Planar Reconstructed (MPR) views, or sets of spatially-related source frames, either parallel or oblique (the cross-hatched boxes in Figure A.59-1). The Ultrasound Image and Ultrasound Multiframe Image IOD’s are used to represent these derived images. See Section A.6 for the Ultrasound Image IOD description or section A.7 for the Ultrasound Multi-frame Image IOD description.
Note: See PS3.17 “3D Ultrasound Volumes” for an informative discussion on the use of these objects for the exchange of 3D ultrasound volume data.
The E-R Model in section A.1.2 depicts those components of the DICOM Information Model that comprise the Enhanced US Volume IOD.
Table A.59-1ENHANCED ULTRASOUND VOLUME IOD MODULES
|Clinical Trial Subject||C.7.1.3||U|
|Clinical Trial Study||C.7.2.3||U|
|Enhanced US Series||C.8.24.1||M|
|Clinical Trial Series||C.7.3.2||U|
|Frame of Reference||Frame of Reference||C.7.4.1||M|
|Ultrasound Frame of Reference||C.8.24.2||M|
|Enhanced General Equipment||C.7.5.2||M|
|Enhanced Contrast/Bolus||C.7.6.4b||C - Required if contrast media was applied. See Section A.220.127.116.11 for baseline context group ID.|
|Multi-frame Functional Groups||C.7.6.16||M|
|Cardiac Synchronization||C.18.104.22.168||C - Required if cardiac synchronization was applied.|
|Respiratory Synchronization||C.22.214.171.124||C - Required if respiratory synchronization was applied.|
|Enhanced Palette Color Lookup Table||C.7.6.23||U|
|Enhanced US Image||C.8.24.3||M|
|IVUS Image||C.8.24.4||C - Required if Modality = IVUS|
|Frame Extraction||C.12.3||C - Required if the SOP Instance was created in response to a Frame-Level retrieve request|
The Acquisition Time Synchronized attribute (0018,1800) shall have a value of ‘Y’ if associated physiological waveforms are linked to the Enhanced US Volume. As described in the Synchronization Module, the same value of the Synchronization Frame of Reference UID (0020,0200) is shared between the Waveform and Enhanced US instances to indicate a common temporal frame of reference for the Acquisition Datetime (0008,002A) values in the waveform and Enhanced US instances. Further, the Frame Reference Datetime attribute (0018,9151) may be used in optimizing alignment between the displayed image and displayed physiological waveforms.
In the case of gated acquisition in which information from multiple events (such as ECG beats) are used to create sub-volumes that are “spliced” or “interleaved” together to form the volume dataset, the Excluded Intervals Module describes the timing of each of the constituent sub-volumes for correlation with the physio waveform.
Note: It is recommended that the Waveform Annotation Module in the General ECG Waveform IOD be used to indicate the times of the R-wave events within the acquisition duration. This allows the viewing application to be able to mark those R-R intervals that contributed to the acquisition of the Enhanced US Volume.
Baseline context ID for the Contrast/Bolus Agent Sequence (0018,0012) in the Enhanced Contrast/Bolus Module is CID 12030.
Table A.59-2 specifies the use of the Functional Group macros used in the Multi-frame Functional Groups Module for the Enhanced US Volume IOD.
Table A.59-2ENHANCED US VOLUME FUNCTIONAL GROUP MACROS
|Functional Group Macro||Section||Usage|
|Frame Content||C.126.96.36.199.2||M - May not be used as a Shared Functional Group.|
|Plane Position (Patient)||C.188.8.131.52.3||U|
|Plane Orientation (Patient)||C.184.108.40.206.4||U|
|Derivation Image||C.220.127.116.11.6||C - Required if the image or frame has been derived from another SOP Instance.|
|Cardiac Synchronization||C.18.104.22.168.7||C - Required if Cardiac Synchronization is used|
|Frame VOI LUT||C.22.214.171.124.10||M|
|Real World Value Mapping||C.126.96.36.199.11||U|
|Contrast/Bolus Usage||C.188.8.131.52.12||C - Required if the Enhanced Contrast/Bolus Module is present|
|Patient Orientation in Frame||C.184.108.40.206.15||U|
|Frame Display Shutter||C.220.127.116.11.16||U|
|Respiratory Synchronization||C.18.104.22.168.17||C - Required if Respiratory Synchronization is used|
|Plane Position (Volume)||C.22.214.171.124.21||M - May not be used as a Shared Functional Group. See A.126.96.36.199.|
|Plane Orientation (Volume)||C.188.8.131.52.22||M - May not be used as a Per-Frame Functional Group. See A.184.108.40.206.|
|Temporal Position||C.220.127.116.11.23||C - Required if frames are temporally related and not temporally referenced to a Cardiac or Respiratory event|
|Image Data Type||C.18.104.22.168.24||M|
|US Image Description||C.22.214.171.124||M - May not be used as a Per-Frame Functional Group|
The value of Volumetric Properties (0008,9206) shall be VOLUME. The value of Volume Based Calculation Technique (0008,9207) shall be NONE.
Image Position (Volume) (0020,9301) first value (X) shall be zero and second value (Y) shall be zero. Image Orientation (Volume) (0020,9302) values shall be 1\0\0\0\1\0. This ensures that the origins of each frame lies on the Volume Frame of Reference Z V axis, the rows of each frame are parallel to the Volume Frame of Reference X V axis, and the columns of each frame are parallel to the Volume Frame of Reference Y V axis.