C.8.15.2 Enhanced CT Image Module

C.8.15.2 Enhanced CT Image Module (Current)
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This section describes the Enhanced CT Image Module. Table C.8-114 specifies the Attributes of the Enhanced CT Image Module.

Table C.8-114. Enhanced CT Image Module Attributes

Attribute Name	Tag	Type	Attribute Description
Image Type	(0008,0008)	1	Image characteristics. See Section C.8.16.1 and Section C.8.15.2.1.1.
Multi-energy CT Acquisition	(0018,9361)	3	Indicates whether the image is created by means of Multi-energy technique. Enumerated Values: YES NO
Include Table C.8-131 “Common CT/MR and Photoacoustic Image Description Macro Attributes”
Acquisition Number	(0020,0012)	3	A number identifying the single continuous gathering of data over a period of time that resulted in this image. Note This number is not required to be unique across SOP Instances in a Series. See also the description of the Referenced Raw Data Sequence (0008,9121).
Acquisition DateTime	(0008,002A)	1C	The date and time that the acquisition of data started. Note The synchronization of this time with an external clock is specified in the Synchronization Module in Acquisition Time Synchronized (0018,1800). See Section C.7.6.16.2.2.1 for an overview of all acquisition related timing Attributes. Required if Image Type (0008,0008) Value 1 of this frame is ORIGINAL or MIXED and SOP Class UID is not "1.2.840.10008.5.1.4.1.1.2.2" (Legacy Converted), may be present otherwise.
Acquisition Duration	(0018,9073)	1C	The time in seconds needed to complete the acquisition of data. See Section C.7.6.16.2.2.1 for further explanation. Required if Image Type (0008,0008) Value 1 of this frame is ORIGINAL or MIXED and SOP Class UID is not "1.2.840.10008.5.1.4.1.1.2.2" (Legacy Converted), may be present otherwise.
Include Table 10.42-1 “Hierarchical Evidence Reference Macro Attributes”
Samples per Pixel	(0028,0002)	1	Number of samples (planes) in this image. This value shall be 1.
Photometric Interpretation	(0028,0004)	1	Specifies the intended interpretation of the pixel data. Enumerated Values: MONOCHROME2 See Section C.7.6.3.1.2 for definition of this term.
Bits Allocated	(0028,0100)	1	Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. This value shall be 16.
Bits Stored	(0028,0101)	1	Number of bits stored for each pixel sample. Each sample shall have the same number of bits stored. This value shall be 12 or16.
High Bit	(0028,0102)	1	Most significant bit for pixel sample data. Each sample shall have the same high bit. Shall be one less than the value in Bits Stored (0028,0101).
Content Qualification	(0018,9004)	1C	Content Qualification Indicator Enumerated Values: PRODUCT RESEARCH SERVICE See Section C.8.13.2.1.1 for further explanation. Required if SOP Class UID is not "1.2.840.10008.5.1.4.1.1.2.2" (Legacy Converted), may be present otherwise.
Image Comments	(0020,4000)	3	User-defined comments about the image.
Burned In Annotation	(0028,0301)	1C	Indicates whether or not the image contains sufficient burned in annotation to identify the patient and date the image was acquired. Enumerated Values: NO This means that images that contain this Module shall not contain such burned in annotations. Required if SOP Class UID is not "1.2.840.10008.5.1.4.1.1.2.2" (Legacy Converted), may be present otherwise.
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.
Lossy Image Compression	(0028,2110)	1C	Specifies whether an Image has undergone lossy compression (at a point in its lifetime). Enumerated Values: 00 Image has not been subjected to lossy compression. 01 Image has been subjected to lossy compression. Once this value has been set to "01" it shall not be reset. See Section C.7.6.1.1.5. Required if SOP Class UID is not "1.2.840.10008.5.1.4.1.1.2.2" (Legacy Converted). May be present otherwise.
Lossy Image Compression Ratio	(0028,2112)	1C	Describes the approximate lossy compression ratio(s) that have been applied to this image. See Section C.7.6.1.1.5.2. Required if Lossy Image Compression (0028,2110) is "01".
Lossy Image Compression Method	(0028,2114)	1C	A label for the lossy compression method(s) that have been applied to this image. See Section C.7.6.1.1.5.1. Required if Lossy Image Compression (0028,2110) is "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.
Icon Image Sequence	(0088,0200)	3	This icon image is representative of the Image. Only a single Item is permitted in this Sequence.
>Include Table C.7-11b “Image Pixel Macro Attributes”			See Section C.7.6.1.1.6.
Include Table 10-25 “Optional View and Slice Progression Direction Macro Attributes”
Include Table C.36.2.4.12-1 “RT Equipment Mapping and Plan Reference Macro Attributes”

Note

Section 10.23 RT Equipment Correlation Macro (Retired) was previously included in this Module but has been retired. See PS3.3-2024b.

C.8.15.2.1 CT Image Description Attribute Description

C.8.15.2.1.1 Image Type and Frame Type

In addition to the requirements specified in Section C.8.16.1 Image Type and Frame Type, the following additional requirements and Defined Terms are specified.

These requirements and Defined Terms are also applicable to Frame Type (0008,9007).

C.8.15.2.1.1.1 Pixel Data Characteristics

Value 1 of Image Type (0008,0008) and Frame Type (0008,9007) is discussed in Section C.8.16.1.1. No additional requirements or Defined Terms.

C.8.15.2.1.1.2 Patient Examination Characteristics

Value 2 of Image Type (0008,0008) and Frame Type (0008,9007) is discussed in Section C.8.16.1.2. No additional requirements or Defined Terms.

C.8.15.2.1.1.3 Image Flavor

Table C.8-115 specifies the Defined Terms for CT additional to those defined in Section C.8.16.1.3 for Value 3 for Image Type (0008,0008) and Frame Type (0008,9007).

Table C.8-115. Image Type and Frame Type Value 3 for CT

Defined Term Name	Defined Term Description
ATTENUATION	Collected for the purpose of performing attenuation corrections (e.g., PET attenuation correction).
CARDIAC_CTA	Images of the heart collected for the purpose of CT Coronary Angiography (CTA).
CARDIAC_CASCORE	Images of the heart collected for the purpose of CT Coronary Calcium Scoring.
REFERENCE	Collected for anatomical reference for PET or SPECT.

C.8.15.2.1.1.4 Derived Pixel Contrast

Table C.8-116 specifies the Defined Terms for CT additional to those defined in Section C.8.16.1.4 for Value 4 for Image Type (0008,0008) and Frame Type (0008,9007).

Table C.8-116. Image Type and Frame Type Value 4 for CT

Defined Term Name	Defined Term Description
FILTERED	An image filter has been applied.
MEDIAN	Pixel by pixel median.
ENERGY_PROP_WT	Image pixels created through proportional weighting of multiple acquisitions at distinct X-Ray energies.

C.8.15.2.1.1.5 Multi-energy CT Images

Table C.8-116b specifies the Defined Terms for CT for Value 5 for Image Type (0008,0008) and Frame Type (0008,9007). Image Type (0008,0008) Value 5 shall be present if Multi-energy CT Acquisition (0018,9361) has a value of YES.

Table C.8-116b. Image Type and Frame Type Value 5 for CT

Defined Term Name	Defined Term Description
VMI	Virtual Monoenergetic Image. Each real-world value mapped pixel represents CT Hounsfield units and is analogous to a CT image created by a monoenergetic (of a specific keV value) X-Ray beam.
MAT_SPECIFIC	Material-Specific Image. Each real-world value mapped pixel value represents a property of a material such as attenuation, concentration or density.
MAT_REMOVED	An image with the attenuation contribution of one or more materials removed. For pixels that did not contain any of the removed material(s), the pixel values are unchanged.
MAT_FRACTIONAL	Material-Fractional Image. Each real-world value mapped pixel represents the fraction of a voxel occupied by a material.
EFF_ATOMIC_NUM	Effective Atomic Number Image. Each real-world value mapped pixel represents Effective Atomic Number of the materials in the voxel.
ELECTRON_DENSITY	Electron Density Image. Each real-world value mapped pixel represents the number of electrons per unit volume or the electron density relative to water.
MAT_MODIFIED	Material-Modified Image. CT Image where real-world value mapped pixels have been modified to highlight a certain target material (either by partially suppressing the background or by enhancing the target material), or to partially suppress the target material.
MAT_VALUE_BASED	Value-Based Image. CT Image where real-world value mapped pixels represent a certain value for a specified material
MIXED	Used only as a value in Image Type (0008,0008) if frames within the image SOP Instance contain different values for Value 5 in their Frame Type (0008,9007).

Note

The Defined Terms in Table C.8-116b are also used as Defined Terms for Value 4 of the CT Image IOD multi-energy Image Type (see Section C.8.2.1.1.1).