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.8-114ENHANCED CT IMAGE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Image Type (0008,0008) 1 Image characteristics. See sections C.8.16.1 and C.8.15.2.1.1.
Include Common CT/MR Image Description Macro' Table C.8-131
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. Notes: 1. The synchronization of this time with an external clock is specified in the synchronization Module in Acquisition Time synchronized (0018,1800) . 2. See 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, may be present otherwise.
Acquisition Duration (0018,9073) 1C The time in seconds needed to complete the acquisition of data. See 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, may be present otherwise.
Referenced Raw Data Sequence (0008,9121) 3 The Raw data that was used to derive this Image. One or more Items are permitted in this Sequence. Note: The items of in this sequence may identify raw data that has not been stored or encoded as a DICOM object. This allows recognition that images in different instances have been reconstructed from the same raw data.
>Include ‘’Hierarchical SOP Instance Reference Macro’ Table C.17-3
Referenced Waveform Sequence (0008,113A) 3 References to waveforms acquired in conjunction with this image. These Waveforms may or may not be temporally synchronized with this image. One or more Items are permitted in this sequence.
>Include ‘’Hierarchical SOP Instance Reference Macro’ Table C.17-3
Referenced Image Evidence Sequence (0008,9092) 1C Full set of Composite SOP Instances referring to image SOP Instances inside the frames of this Enhanced CT Image SOP Instance. See C.8.13.2.1.2 for further explanation. One or more Items shall be included in this sequence. Required if the Referenced Image Sequence (0008,1140) is present.
>Include ‘’Hierarchical SOP Instance Reference Macro’ Table C.17-3
Source Image Evidence Sequence (0008,9154) 1C Full set of Composite SOP Instances used as source image SOP Instances inside the frames of this Enhanced CT Image SOP Instance. See C.8.13.2.1.2 for further explanation. One or more Items shall be included in this sequence. Required if the Source Image Sequence (0008,2112) is present.
>Include ‘’Hierarchical SOP Instance Reference Macro’ Table C.17-3
Referenced Presentation State Sequence (0008,9237) 1C References to Presentation State instances acquired in conjunction with this instance. Note: May only be used to reference Presentation States belonging to the acquired data and not to reference Presentation States generated subsequently such as during interpretation. One or more Items shall be included in this sequence. Required if Presentation State is generated during acquisition, shall not be present otherwise.
>Include '’Hierarchical SOP Instance Reference Macro' Table C.17-3
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 Value: MONOCHROME2. See 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) 1 Content Qualification Indicator Enumerated Values: PRODUCT RESEARCH SERVICE See C.8.13.2.1.1 for further explanation.
Image Comments (0020,4000) 3 User-defined comments about the image
Burned In Annotation (0028,0301) 1 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.
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) 1 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 for further explanation.
Lossy Image Compression Ratio (0028,2112) 1C Describes the approximate lossy compression ratio(s) that have been applied to this image. See C.7.6.1.1.5 for further explanation. May be multivalued if successive lossy compression steps have been applied. Note: For example, a compression ratio of 30:1 would be described in this Attribute with a single value of 30. Required if Lossy Images 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 C.7.6.1.1.5 for further explanation. May be multivalued if successive lossy compression steps have been applied; the value order shall correspond to the values of Lossy Image Compression Ratio (0028,2112). 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 ‘Image Pixel Macro’ Table C.7-11b See Section F.7.

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 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 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 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 C.8.16.1.3 for Value 3 for Image Type (0008,0008) and Frame Type (0008,9007).

Table C.8-115IMAGE 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)
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 C.8.16.1.4 for Value 4 for Image Type (0008,0008) and Frame Type (0008,9007).

Table C.8-116IMAGE 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.