DICOM PS3.3 2024b - Information Object Definitions

C.8.15.2 Enhanced CT Image Module

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

  1. The synchronization of this time with an external clock is specified in the Synchronization Module in Acquisition Time Synchronized (0018,1800).

  2. 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”

Isocenter Position

(300A,012C)

3

Isocenter coordinates (x,y,z), in mm. Specifies the location of the machine isocenter in the Patient-Based Coordinate System associated with the Frame of Reference. It allows transformation from the Equipment-Based Coordinate System to the Patient-Based Coordinate System.

Include Table 10-27 “RT Equipment Correlation Macro Attributes”


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).

DICOM PS3.3 2024b - Information Object Definitions