C.8.24 Enhanced US Volume Modules and Functional Group Macros

C.8.24.1 Enhanced US Series Module

Table C.8.24.1-1 specifies attributes for the Enhanced US Series Module, including specialization of attributes in the General Series Module for use in the Enhanced US Series Module.

Table C.8.24.1-1ENHANCED US SERIES MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Modality (0008,0060) 1 Type of equipment that originally acquired the data used to create the images in this Series. Enumerated Values: US IVUS See section C.7.3.1.1.1 for further explanation.
Referenced Performed Procedure Step Sequence (0008,1111) 1C Uniquely identifies the Performed Procedure Step SOP Instance to which the Series is related (e.g. a Modality or General-Purpose Performed Procedure Step SOP Instance). Only a single Item shall be included in this sequence. Required if the Modality Performed Procedure Step SOP Class or General Purpose Performed Procedure Step SOP Class is supported.
>Include ‘SOP Instance Reference Macro' Table 10-11
Performed Protocol Code Sequence (0040,0260) 1C Sequence describing a Protocol being followed for this Procedure Step. Only a single Item shall be included in this sequence. Required if a Protocol is controlling the creation of this Series. May be present otherwise.
>Include ‘Code Sequence Macro’ Table 8.8-1 Baseline Context ID 12001
>Protocol Context Sequence (0040,0440) 3 Sequence that specifies the context for the Performed Protocol Code Sequence Item. One or more items are permitted in this sequence.
>>Include ‘Content Item Macro’ Table 10-2 No Baseline Template is defined.
>>Content Item Modifier Sequence (0040,0441) 3 Sequence that specifies modifiers for a Protocol Context Content Item. One or more items are permitted in this sequence. See Section C.4.10.1.
>>>Include ‘Content Item Macro’ Table 10-2 No Baseline Template is defined.
Performed Protocol Type (0040,0261) 1C Type of protocol performed. Enumerated Values: STAGED NON_STAGED Required if Performed Protocol Code Sequence (0040,0260) is present.

C.8.24.2 Ultrasound Frame of Reference Module

Table C.8.24.2-1 specifies the attributes of the Ultrasound Frame Of Reference Module. See C.8.24.2.1 for an overview of the Ultrasound Frame Of Reference Module.

Table C.8.24.2-1ULTRASOUND FRAME OF REFERENCE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Volume Frame of Reference UID (0020,9312) 1 Uniquely identifies this Volume Frame of Reference.
Ultrasound Acquisition Geometry (0020,9307) 1 Characteristic of the ultrasound acquisition geometry. Defined Terms: APEX = there exists an apex of the scan lines from which the volume data was acquired.
Apex Position (0020,9308) 1C Position of the apex (or phase center) of the acquisition geometry, encoded as xA, yA, and zA in mm units in the Volume Frame of Reference. The apex (xA, yA, zA) may be located in the volume or exterior to it. Required if value of Ultrasound Acquisition Geometry (0020,9307) is APEX.
Volume to Transducer Mapping Matrix (0020,9309) 1 A 4x4 homogeneous transformation matrix that maps the Volume Frame of Reference coordinate system (XV, YV, ZV) to the Transducer Frame of Reference coordinate system (XX,YX, ZX). Matrix elements shall be listed in row-major order. See Section C.8.24.2.1 for details.
Patient Frame of Reference Source (0020,930C) 1C Indicates how the supplied Image Position (Patient) (0020,0032) and Image Orientation (Patient) (0020,0037) values are obtained. Enumerated Values: TABLE A positioning device, such as a gantry, was used to generate these values. ESTIMATED Estimated patient position / orientation (eg, estimated by the user), or if reliable information is not available. REGISTRATION Acquisition has been spatially registered to a prior image set. Required if either Image Position (Patient) (0020,0032) or Image Orientation (Patient) (0020,0037) is present.
Table Frame of Reference UID (0020,9313) 1C Uniquely identifies this Table Frame of Reference. Required if Patient Frame of Reference Source (0020,930C) is TABLE.
Volume to Table Mapping Matrix (0020,930A) 1C A 4x4 homogeneous transformation matrix that maps the Volume Frame of Reference coordinate system (XV,YV, ZV) to the Table Frame of Reference coordinate system (XT,YT, ZT). Matrix elements shall be listed in row-major order. See Section C.8.24.2.2 for details. Required if Patient Frame of Reference Source (0020,930C) is TABLE.

C.8.24.2.1 Ultrasound Frame of Reference Module Overview

The Ultrasound Frame of Reference Module is used to relate the image planes to a frame of reference appropriate for the ultrasound modality, most notably a volume-based frame of reference. There are many different transducer scan acquisition geometries used in 3D ultrasound imaging. Regardless of the acquisition geometry, after acquisition of the initial scan images comprising the volume, the ultrasound (US) scanner will assemble (reformat) the data into a proper Cartesian volume with the assumption that the data are related through a Right-Hand Coordinate System (RHCS). x-positions are defined in mm with positive values increasing towards the right. y-positions are defined in mm with positive values in the direction of increasing image depth. z-positions are defined in mm with positive values in the direction as defined in a right-hand coordinate system.

A Cartesian volume will consist of a series of 1 to n parallel planes. The image planes comprising the Cartesian volume are typically oriented during creation of the volume so that the best image quality is in the XY plane. Table C.8.24.2-1 specifies the attributes of the Ultrasound Frame of Reference Module. There are three levels of detail for the Ultrasound Frame of Reference: Volume, Transducer and Table.

C.8.24.2.1.1 Volume Frame of Reference

The Volume Frame of Reference is a Right-hand Coordinate System consisting of a Volume Origin at the location (0,0,0) and mutually orthogonal X V , Y V , and Z V axes in a Right-Hand Coordinate System. The particular IOD using the Volume Frame of Reference may constrain the alignment of frames with respect to the axes of the Volume Frame of Reference. For example, Figure C.8.24.2-1 illustrates the use of the Volume Frame of Reference with frames whose rows are parallel to the X V axis and columns are parallel to the Y V axis and whose origins lie on the Z V axis.

[pic]

Figure C.8.24.2-1: Volume Frame of Reference

C.8.24.2.1.2 Transducer Frame of Reference

The Transducer Frame of Reference is a Right-hand Coordinate System consisting X X , Y X , and Z X axes originating at a reference “Transducer Origin” defined as the geometric center of the transducer face.

The orientation of the Transducer Frame of Reference relative to the Volume Origin is such that the Y X axis is normal to the transducer face and the “direction reference” ( i.e. transducer tactile marker or zero reference) is aligned with the positive X X axis. A transformation is specified between the Volume Frame of Reference and the Transducer Frame of Reference to define the position of the transducer relative to the volume. This transformation is specified by the Volume to Transducer Mapping Matrix (0020,9309).

The Transducer Frame of Reference recognizes two types of scan geometry: 1) a scan geometry with a real apex such as would be the case for a pyramid, toroid or rotational volume acquisition, or 2) a scan geometry for which there is no specific apex. The point (x A , y A , z A ) is the apex (or phase center) of the acquisition volume geometry in the Volume Frame of Reference. The apex (x A , y A , z A ) may be located in the volume or exterior to it.

[pic]

Figure C.8.24.2-2: Transducer Frame of Reference

C.8.24.2.1.3 Table Frame of Reference

There also may exist a fixed equipment reference called the Table Frame of Reference, a Right-hand Coordinate System consisting of X T , Y T , and Z T axes originating at a reference “Table Origin”. See Figure C.8.24.2-3.

Note: In this context the Table Frame of Reference refers to a fixed coordinate system in space that may be provided by a variety of source devices such as coordinates from a magnetic position sensor, LED sensor array, a physical scanner gantry, or similar device.

A transformation may be specified between the Volume Frame of Reference and the Table Frame of Reference to define the position and orientation of the volume relative to this external frame of reference. This transformation is specified by the Volume to Table Mapping Matrix (0020,930A).

[pic]

Figure C.8.24.2-3: Table Frame of Reference

C.8.24.2.2 Ultrasound Frame of Reference Module Attributes

C.8.24.2.2.1 Volume to Transducer Mapping Matrix

The Volume to Transducer Mapping Matrix (0020,9309) is used to describe the relationship between the Transducer Frame of Reference coordinate system and the Volume Frame of Reference coordinate system.

The Volume to Transducer Mapping Matrix ([M TV ]=[P]*[Q]) describes how to transform a point (X V , Y V , Z V ) in the Volume coordinate system into (X X ,Y X , Z X ) in the Transducer coordinate system according to the equation below.

[pic]

Where:

X V Y V Z V The voxel location (in mm) in the Volume Frame of Reference

X X Y X Z X The voxel location (in mm) in the Transducer Frame of Reference

Pij,Pij,Pij A 3x3 matrix of direction cosine values as measured to the Transducer origin from the volume origin.

Qx,Qy,QzThe translation values (in mm) describe the location in mm of the Transducer Frame of Reference (X X ,Y X , Z X ) origin from the Volume Reference Origin (X V ,Y V , Z V )measured in millimeters along the Volume axes i.e. to the transducer origin from the volume origin.

C.8.24.2.2.2 Volume to Table Mapping Matrix

The Volume to Table Mapping Matrix (0020,930A) is used to describe the relationship between the Volume Frame of Reference coordinate system and a modality specific equipment coordinate system. This mapping can be used only with systems that have a well-defined equipment coordinate system.

The Volume to Table Mapping Matrix ([M VG ]=[R]*[S]) describes how to transform a point (X V Y V Z V ) in the Volume coordinate system into (X T , Y T , Z T ) in the Table coordinate system according to the equation below.

[pic]

Where:

X V Y V Z V The voxel location (in mm) in the Volume Frame of Reference

X T Y T Z T The voxel location (in mm) in the Table Frame of Reference

Rij,Rij,Rij A 3x3 matrix of direction cosine values as measured to the gantry origin from the volume origin.

Sx,Sy,SzThe translation values (in mm) describe the location in mm of the Table Frame of Reference (X T , Y T , Z T ) origin from the Volume Reference Origin (X V ,Y V , Z V )measured in millimeters along the table axes I.e. to the table origin from the volume origin.

Note: The Mapping Matrices are rigid transformations that involve only translations and rotations. Mathematically, the matrix is orthonormal and describes six degrees of freedom: three translations, and three rotations.

C.8.24.3 Enhanced US Image Module

Table C.8.24.3-1 specifies the Attributes that describe the Enhanced US Image Module. As described in Section A.1.2.6, the Attributes in this Module apply to the first frame of a multi-frame image; any or all of this information may be overridden by Attributes in Per-frame Functional Groups.

Table C.8.24.3-1ENHANCED US IMAGE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Image Type (0008,0008) 1 Image identification characteristics. See C.8.24.3.2 for specialization.
Samples Per Pixel (0028,0002) 1 Number of samples per pixel in this image. Enumerated value: 1
Photometric Interpretation (0028,0004) 1 Specifies the intended interpretation of the pixel data. Enumerated value: MONOCHROME2
Bits Allocated (0028,0100) 1 Number of bits allocated for each pixel sample. Enumerated values: 8, 16
Bits Stored (0028,0101) 1 Number of bits stored for each pixel sample. Enumerated values: 8, 16
High Bit (0028,0102) 1 Most significant bit for pixel sample data. Enumerated values: 7, 15
Pixel Representation (0028,0103) 1 Data representation of pixel samples. The constrained enumerated value implies the VR of all Palette Color Lookup Table Descriptors be US (and not SS). Enumerated value: 0000H = unsigned integer See C.8.24.3.1 for specialization.
Dimension Organization Type (0020,9311) 1 Dimension organization of the instance. Enumerated Values: 3D 3D_TEMPORAL See C.8.24.3.3 for details.
Acquisition Datetime (0008,002A) 1 The date and time that the acquisition of data that resulted in this image started.
Acquisition Duration (0018,9073) 1 Duration of the image acquisition in ms.
Pixel Spacing (0028,0030) 1 Physical distance in the patient between the centers of adjacent pixels, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing, in mm. See 10.7.1.3 for further explanation of the value order.
Position Measuring Device Used (0018,980C) 1C Indicates the position measuring device used in the acquisition of the image, which implies the degree of precision of the Pixel Spacing (0028,0030) and Spacing Between Slices (0018,0088) values. Enumerated Values: RIGID The image was acquired with a position measuring device. FREEHAND The image was acquired without a position measuring device. Required if Volumetric Properties (0008,9206) is VOLUME and Volume Based Calculation Technique (0008,9207) is NONE. May be present otherwise.
Lossy Image Compression (0028,2110) 1C Specifies whether an Image has undergone lossy compression. Enumerated Values: 00 Image has NOT been subjected to lossy compression. 01 Image has been subjected to lossy compression. See C.7.6.1.1.5 Required if Lossy Compression has been performed on the Image.
Lossy Image Compression Ratio (0028,2112) 1C See C.7.6.1.1.5 for further explanation. Required if Lossy Image Compression (0028,2110) equals 01.
Lossy Image Compression Method (0028,2114) 1C A label for the lossy compression method(s) that have been applied to this image. See C.7.6.1.1.5 for further explanation. May be multi valued if successive lossy compression steps have been applied; the value order shall correspond to the values of Lossy Image Compression Ratio (0028,2112). Note: For historical reasons, the lossy compression method may also be described in Derivation Description (0008,2111). Required if Lossy Image Compression (0028,2110) equals 01.
Presentation LUT Shape (2050,0020) 1 Specifies an identity transformation for the Presentation LUT, such that the output of all grayscale transformations defined in the IOD containing this Module are defined to be P-Values. Enumerated Values: IDENTITY - output is in P-Values.
Rescale Intercept (0028,1052) 1 The value b in relationship between stored values (SV) and the output units. Output units = m*SV + b. Enumerated value 0
Rescale Slope (0028,1053) 1 m in the equation specified by Rescale Intercept (0028,1052). Enumerated value 1
Source Image Sequence (0008,2112) 1C A Sequence that identifies the set of Image SOP Class/Instance pairs of the Images that were used to derive this Image. One or more Items shall be included in this Sequence. See C.7.6.1.1.4 for further explanation. Required if Image Type (0008,0008) Value 1 is DERIVED.
>Include ‘Image SOP Instance Reference Macro’ Table 10-3
>Purpose of Reference Code Sequence (0040,A170) 1 Describes the purpose for which the reference is made. Only a single item shall be included in this sequence.
>>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 7202
Referenced Image Sequence (0008,1140) 3 A sequence that references other images significantly related to this image. (e.g., an image containing spatially related frames) One or more Items are permitted in this sequence.
>Include ‘Image SOP Instance Reference Macro’ Table 10-3
>Purpose of Reference Code Sequence (0040,A170) 1 Describes the purpose for which the reference is made. Only a single item shall be included in this sequence.
>>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 7201
Referenced Raw Data Sequence (0008,9121) 3 A sequence that identifies the set of Raw Data SOP Class/Instance pairs of the raw data that were used to derive this Image. One or more Items are permitted in this Sequence.
>Include ‘'Hierarchical SOP Instance Reference Macro’ Table C.17-3
Referenced Instance Sequence (0008,114A) 1C A sequence which provides reference to a set of non-image SOP Class/Instance pairs significantly related to this Image, including waveforms that may or may not be temporally synchronized with this image. One or more Items shall be included in this sequence. Required if waveforms are acquired in conjunction with image acquisition. May be present otherwise.
>Include ‘SOP Instance Reference Macro’ Table 10-11
>Purpose of Reference Code Sequence (0040,A170) 1 Code describing the purpose of the reference to the Instance(s). Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1 Defined CID 7004 for referenced waveforms.
Number of Stages (0008,2124) 1C Number of stages in this protocol. Required if Performed Protocol Type (0040,0261) is present with value STAGED.
Stage Number (0008,2122) 1C A number that identifies the Stage. Stage Number starts at one. Required if Performed Protocol Type (0040,0261) is present with value STAGED.
Stage Code Sequence (0040,000A) 1C Sequence describing the performed Ultrasound Protocol Stage. Only a single item shall be included in this sequence. Required if Performed Protocol Type (0040,0261) is present with value STAGED.
>Include ‘Code Sequence Macro’ Table 8.8-1 Baseline CID 12002
View Code Sequence (0054,0220) 1 Sequence that describes the view of the patient anatomy in this image. Only a single Item shall be included in this Sequence. See Section C.8.5.6.1.19.
>Include ‘Code Sequence Macro’ Table 8.8-1 See Section C.8.5.6.1.19 for Context Group ID’s
>View Modifier Code Sequence (0054,0222) 3 Sequence that provides modifiers for the view of the patient anatomy. One or more Items are permitted in this Sequence. See Section C.8.5.6.1.19.
>>Include ‘Code Sequence Macro’ Table 8.8-1 See Section C.8.5.6.1.19 for Context Group ID’s
Event Timer Sequence (0008,2133) 3 Sequence of time intervals of significance to this image. Each item describes one time interval either beginning or ending at Acquisition Datetime (0008,002A). One or more Items are permitted in this Sequence.
>Event Time Offset (0008,2134) 1 Signed value of the time between Acquisition Datetime (0008,002A) and the event, in milliseconds. Positive values indicate the event occurs after Acquisition Datetime (0008,002A).
>Event Code Sequence (0008,2135) 1 Type of event. Only a single item shall be included in this sequence.
>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 12031
>Event Timer Name(s) (0008,2132) 3 Name that identifies the event timer. May be used in addition to Event Time Code Sequence to offer site-specific user-readable event time names. Only a single value shall be included.
Include 'General Anatomy Mandatory Macro' Table 10-5 No Context IDs are specified.
Burned In Annotation (0028,0301) 1 Indicates whether or not image contains sufficient burned in annotation to identify the patient and date the image was acquired. Enumerated Value: NO
Recognizable Visual Features (0028,0302) 3 Indicates whether or not the image contains sufficiently recognizable visual features to allow the image or a reconstruction from a set of images to identify the patient. Enumerated Values: YES NO If this Attribute is absent, then the image may or may not contain recognizable visual features.
Icon Image Sequence (0088,0200) 3 This icon image is representative of the image. Only a single item is permitted in this sequence.
>Include ‘Image Pixel Macro’ Table C.7-11b See C.7.6.1.1.6 for further explanation.
Transducer Data (0018,5010) 3 Manufacturer defined code or description
Transducer Scan Pattern Code Sequence (0018,9809) 1 The scan pattern the transducer is capable of. Only a single item shall be included in this sequence. See C.8.24.3.4 for further explanation.
>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 12032.
Transducer Geometry Code Sequence (0018,980D) 1 Geometric structure of the transducer. Only a single item shall be included in this sequence. See C.8.24.3.4 for further explanation.
>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 12033.
Transducer Beam Steering Code Sequence (0018,980E) 1 Technique used by the transducer for beam steering. One or more items shall be included in this sequence. If more than one item is present, the order is significant from plane-forming technique to volume-forming technique. See C.8.24.3.4 for further explanation.
>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 12034.
Transducer Application Code Sequence (0018,980F) 1 The primary clinical application of the transducer. Only a single Item shall be included in this sequence. See C.8.24.3.4 for further explanation.
>Include ‘Code Sequence Macro’ Table 8.8-1 Defined CID 12035.
Preprocessing Function (0018,5020) 3 Manufacturer defined description of processing of echo information. Data may include code or description of gain (initial, overall, TGC, dynamic range, etc.), pre-processing, post-processing, Doppler processing parameters, e.g. cutoff filters, etc., as used in generating a given image.
Mechanical Index (0018,5022) 1 See C.8.5.6.1.8 for Description.
Bone Thermal Index (0018,5024) 1 See C.8.5.6.1.8 for Description.
Cranial Thermal Index (0018,5026) 1 See C.8.5.6.1.8 for Description.
Soft Tissue Thermal Index (0018,5027) 1 See C.8.5.6.1.8 for Description.
Depth(s) of Focus (0018,9801) 1 The depth or depths from the transducer face, of the manufacturer defined beam focus points used for the image, in mm.
Depth of Scan Field (0018,5050) 1 The depth, in mm, from the transducer face to the deepest point included in the image- the field of view.

C.8.24.3.1 Pixel Representation

Pixel Representation (0028,0103) is specified to be Type 1 with the constraint that VR for all the pixel data will always be unsigned (US) and not signed (SS).

Enumerated Value: 0000H = unsigned integer

Note: The real-world values that are inherently signed (example: Flow Velocity, Tissue Velocity, Variance …) are represented as unsigned, unitless pixel values and may be mapped to signed real-world quantities via the Real World Value Mapping Macro.

C.8.24.3.2 Image Type

Image Type (0008,0008) is specified to be Type 1 with the following constraints:

Value 1 shall have a value of ORIGINAL or DERIVED

Value 2 shall have a value of PRIMARY

Value 3 (Image Flavor) and Value 4 are not used

C.8.24.3.3 Dimension Organization Type

Dimension Organization Type (0020,9311) specifies the general structure of the image. The concept of “multi-frame dimensions” as specified by the Dimension Index Sequence (0020,9222) and per-frame Dimension Index Values (0020,9157) shall be used to specify the relationships of frames within that general structure.

If Dimension Organization Type (0020,9311) has values of 3D or 3D_TEMPORAL, then the Dimension Index Sequence (0020,9222) shall have exactly three items, with the dimension values described in Table C.8.24.3.3-1.

Table C.8.24.3.3-1DIMENSION DEFINITION FOR US ACQUISITION 3D IMAGES

Item Attribute Tag Value
Dimension Index Sequence (0020,9222)
1st >Dimension Index Pointer (0020,9165) Tag of attribute specifying temporal position of frames
>Functional Group Pointer (0020,9167) Tag of sequence containing above attribute
2nd >Dimension Index Pointer (0020,9165) (0020,9301) Image Position (Volume)
>Functional Group Pointer (0020,9167) (0020,930E) Plane Position (Volume) Sequence
3rd >Dimension Index Pointer (0020,9165) (0018,9808) Data Type
>Functional Group Pointer (0020,9167) (0018,9807) Image Data Type Sequence

The Dimension Index Values (0020,9157) corresponding to these dimension variables positively associate frames with different Data Type values at the same spatial and temporal position. Figure C.8.24.3.3-1 illustrates the use of Dimensions to associate frames with temporal, spatial, and Data Type dimensions.

These Dimension values shall be used even if there is only one possible value for a Dimension.

Note: For example, if Dimension Organization Type (0020,9311) has the value 3D, the temporal position dimension is present and the dimension index of the temporal attribute is the same in every frame of the image. Similarly, if the Data Type attribute is in the Shared Functional Group and all frames in the object are of Data Type TISSUE_INTENSITY, the Data Type dimension is present and the dimension index of the Data Type dimension is the same in every frame of the image.

Each plane in the volume consists of one or more frames each with a distinct value of Data Type (0018,9808). The planes in the cartesian volume shall have equal inter-plane spacing, accomplished through values of Image Position (Volume) (0020,9301).

Each frame comprising a volume shall have the same value of the temporal dimension attribute. Any appropriate physiological event temporal attribute may be used to specify the temporal position. If there is no specific physiological event to which the temporal position of frames is referenced, then Temporal Position Time Offset (0020,930D) in the Temporal Position Sequence (0020,9310) may be used as the temporal dimension attribute. If all frames are at the same temporal position, any temporal attribute may be referenced.

Note: For example, the attribute specifying temporal position of frames may be any appropriate temporal attribute, such as Nominal Cardiac Trigger Delay Time (0020,9153) or Nominal Percentage of Cardiac Phase (0020,9241) in the Cardiac Synchronization Sequence (0018,9118) if the temporal position of frames is referenced to the cardiac R-wave, or Nominal Respiratory Trigger Delay Time (0020,9255) or Nominal Percentage of Respiratory Phase (0020,9245) in the Respiratory Synchonization Sequence (0020,9253) if the temporal position of frames is referenced to the latest inspiration maximum.

[pic]

Figure C.8.24.3.3-1 Dimension Organization Type Frame Relationships

C.8.24.3.4 Transducer Description

The following elements together describe the type of transducer used to acquire the image. These are characteristics of the transducer itself rather than its specific use in the acquisition of this image. In other words, these attribute values are determined from the construction and design of the transducer and a given transducer generally has the same values of these attributes in every image it is used to create.

The shape of the acoustic scan field the transducer is capable of.

The physical scan aperture from which acoustic pulses are emitted and received.

The method used to steer acoustic beam.

The placement on the subject for which the transducer is designed.

Each probe model has a unique set of values of these attributes. For example, these sample probes have the following characteristics which are encoded in the attributes above:

Table C.8.24.3.4-1 SAMPLE TRANSDUCER CHARACTERISTICS

Model Scan Pattern Geometry Beam Steering Application
Pedoff CW Line NonImaging Fixed direction External
Phased array sector probe Plane Sector Phased External
Steerable TEE Plane Sector Phased, Mechanical Transesophogeal
Curved Linear Abdominal Plane Curved Linear Phased External
Endovaginal Plane Curved Linear Phased Endovaginal
Mechanical 3D Volume Sector Phased, Mechanical External
Phased 3D Volume Sector Phased External
Endovaginal 3D Volume Curved Linear Phased, Mechanical Endovaginal

C.8.24.4 IVUS Image Module

Table C.8.24.4-1 specifies the Attributes of an IVUS Module.

Table C.8.24.4-1 IVUS IMAGE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
IVUS Acquisition (0018,3100) 1 Defined Terms: MOTOR_PULLBACK MANUAL_PULLBACK SELECTIVE GATED_PULLBACK See C.8.5.6.1.21
IVUS Pullback Rate (0018,3101) 1C Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK. Specified in units of mm/sec. See C.8.5.6.1.22
IVUS Gated Rate (0018,3102) 1C Required if IVUS Acquisition (0018,3100) value is GATED_PULLBACK. Specified in units of mm/beat. See C.8.5.6.1.23
IVUS Pullback Start Frame Number (0018,3103) 1C Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK or GATED_PULLBACK. See C.8.5.6.1.24
IVUS Pullback Stop Frame Number (0018,3104) 1C Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK or GATED_PULLBACK. See C.8.5.6.1.25

C.8.24.5 Excluded Intervals Module

The Excluded Intervals Module indicates those periods within the Acquisition Duration (0018,9073) during which no volume acquisition takes place. It provides information not available at the frame level or image level, since individual frames of the volume may have been built-up over a time period within which some intervals were excluded from acquisition. Further, it provides information that is not specific to associated waveform objects since the fact that volume acquisition was excluded during these intervals is a characteristic of the volume, not the associated waveform(s). Table C.8.24.5-1 specifies the attributes of the Excluded Intervals Module.

Note: For example, if the imaging device performing a gated volume acquisition excludes volume data acquired during an ectopic beat, the Excluded Intervals attributes would be used to mark this interval in an associated physio waveform display.

Table C.8.24.5-1EXCLUDED INTERVALS MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Excluded Intervals Sequence (0018,9803) 1C List of excluded intervals. One or more items shall be included in this sequence. Required if one or more intervals was excluded.
>Exclusion Start Datetime (0018,9804) 1 Time-point of the exclusion start in the same Synchronization Frame of Reference as Acquisition Datetime (0008,002A).
>Exclusion Duration (0018,9805) 1 Duration of the exclusion in ms.

[pic]

Figure C.7.6.16-2: Relationship of Timing Related Attributes

C.8.24.6 Enhanced US Volume Functional Group Macros

The following sections contain Functional Group macros specific to the Enhanced US Volume IOD.

Note: The attribute descriptions in the Functional Group Macros are written as if they were applicable to a single frame (i.e., the macro is part of the Per-frame Functional Groups Sequence). If an attribute is applicable to all frames (i.e. the macro is part of the Shared Functional Groups Sequence) the phrase “this frame” in the attribute description shall be interpreted to mean “ for all frames”.

C.8.24.6.1 US Image Description Macro

Table C.8.24.6.1-1 specifies the attributes of the US Image Description Functional Group Macro.

Table C.8.24.6.1-1US IMAGE DESCRIPTION MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
US Image Description Sequence (0018,9806) 1 A sequence that describes a general description of this image or frame. Only a single Item shall be included in this sequence.
>Frame Type (0008,9007) 1 Type of Frame. A multi-valued attribute analogous to the Image Type (0008,0008). Enumerated Values and Defined Terms are the same as those for the four values of the Image Type (0008,0008) attribute, except that the value MIXED is not allowed. See section C.8.24.3.2.
>Volumetric Properties (0008,9206) 1 Indication if geometric manipulations are possible with frames in the SOP Instance. See C.8.16.2.1.2 for a description and Enumerated Values.
>Volume Based Calculation Technique (0008,9207) 1 Method used for volume calculations with frames in the SOP Instance. See C.8.16.2.1.3 for a description and Defined Terms.

If Volumetric Properties (0008,9206) is VOLUME and Volume Based Calculation Technique (0008,9207) is NONE, all frames in the frame set shall be spaced the same Z-distance from adjacent frames (i.e., spacing between slices is constant).