C.8.27.2 Intravascular OCT Image Module

Table C.8.27.2-1 specifies the Attributes that describe an Image produced by Intravascular OCT imaging modalities.

Table C.8.27.2-1INTRAVASCULAR OCT IMAGE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Image Type (0008,0008) 1 Image identification characteristics. See C.8.27.2.1 for specialization.
Volumetric Properties (0008,9206) 1 Indication if geometric manipulations are possible with frames in the SOP Instance. See C.8.27.2.2.
Pixel Presentation (0008,9205) 1 Indication of the presence or absence of color information that may be used during rendering. See C.8.27.2.3 for a description and Enumerated Values.
Samples Per Pixel (0028,0002) 1 Number of samples (planes) in this image. Enumerated value shall be 1.
Acquisition Datetime (0008,002A) 1 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) .
Acquisition Duration (0018,9073) 1C The scan time in seconds used to create all frames of an Intravascular Optical Coherence Tomography image. Required if Image Type (0008,0008) Value 1 is ORIGINAL. May be present otherwise.
Acquisition Number (0020,0012) 1 A number identifying the single continuous gathering of data over a period of time which resulted in this image.
Photometric Interpretation (0028,0004) 1 Specifies the intended interpretation of the pixel data. Enumerated Value shall be MONOCHROME2.
Pixel Representation (0028,0103) 1 Data representation of pixel samples. Enumerated Value shall be 0.
Bits Allocated (0028,0100) 1 Number of bits allocated for each pixel sample. See C.8.27.2.4 for specialization.
Bits Stored (0028,0101) 1 Number of bits stored for each pixel sample. See C.8.27.2.4 for specialization.
High Bit (0028,0102) 1 Most significant bit for pixel sample data. High Bit (0028,0102) shall be one less than Bits Stored (0028,0101).
Presentation LUT Shape (2050,0020) 1C 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 Value: IDENTITY = output is in P-Values. Required if Presentation Intent Type (0008,0068) equals FOR PRESENTATION.
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 tag has been set to 01 it shall not be reset. See C.7.6.1.1.5 Required if Lossy Compression has been performed on the Image.
Lossy Image Compression Ratio (0028,2112) 1C Describes the approximate lossy compression ratio(s) that have been applied to this image. Required if Lossy Image Compression (0028,2110) has a value of “01”. See C.7.6.1.1.5 for further explanation. May be multi-valued if successive lossy compression steps have been applied. Notes: 1. For example, a compression ratio of 30:1 would be described in this Attribute with a single value of 30. 2. For historical reasons, the lossy compression ratio should also be described in Derivation Description (0008,2111).
Lossy Image Compression Method (0028,2144) 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). Required if Lossy Image Compression (0028,2110) has a value of “01”. Note: For historical reasons, the lossy compression method should also be described in Derivation Description (0008,2111).
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) 1 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: NO
Referenced Instance Sequence (0008,114A) 3 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 are permitted in this sequence.
>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 SOP Instances. Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1 Defined Context ID is CID 7004 for referenced waveforms.
Image Comments (0020,4000) 3 User-defined comments about the image.
Recommended Display Frame Rate (0008,2144) 3 Recommended rate at which the frames of an Intravascular OCT image should be displayed in frames/second.
Interpolation Type (0052,0039) 1C The type of interpolation used for the Polar to Cartesian scan-conversion. Defined Terms: REPLICATE BILINEAR CUBIC Required if Presentation Intent Type (0008,0068) equals FOR PRESENTATION.
Referenced Color Palette Instance UID (0028,0304) 1C The identifier of a color palette (i.e., an instance of the Color Palette Storage SOP Class “1.2.840.10008.5.1.4.39.1”) that may be used during rendering. See PS 3.4 Color Palette Storage Service Class and PS 3.6 Well-Known Color Palettes. Required if Pixel Presentation (0008,9205) is COLOR_REF.

C.8.27.2.1 Image Type and Frame Type

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

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.

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.

Value 3 of Image Type (0008,0008) and Frame Type (0008,9007) is discussed in C.8.16.1.3. .

Table C.8.27.2-2 specifies the Defined Terms for IVOCT for Value 3 for Image Type (0008,0008) and Frame Type (0008,9007).

Table C.8.27.2-2 IVOCT IMAGE TYPE AND FRAME TYPE VALUE 3

Defined Term Name Defined Term Description
AXIAL An image that has an orientation that is perpendicular to the long axis of the vessel. (I.e. cross-sectional).
LONGITUDINAL An image that has an orientation that is parallel to the long axis of the vessel.

Value 4 of Image Type (0008,0008) and Frame Type (0008,9007) is discussed in C.8.16.1.4. No additional requirements or Defined Terms.

C.8.27.2.2 Volumetric Properties

The value of the Volumetric Properties attribute (0008,9206) allows applications doing geometric manipulations to determine if the image is an appropriate candidate for an operation without having to know all the details of the generating application.

Table C.8.27.2-3 specifies the Enumerated Values for the Volumetric Properties (0008,9206) attribute.

Table C.8.27.2-3VOLUMETRIC PROPERTIES ATTRIBUTE VALUES

Enumerated Value Name Enumerated Value Description
DISTORTED Frames do not represent the true geometry of the vessel.

C.8.27.2.3 Pixel Presentation

Pixel Presentation (0008,9205) is used to indicate whether a color tint is intended to be applied to the IVOCT image. See Table C.8.27.2-4.

Table C.8.27.2-4PIXEL PRESENTATION ATTRIBUTE VALUES

Enumerated Value Name Enumerated Value Description
COLOR Image is intended to be displayed in color using Supplemental Palette Color LUTs, but can be displayed in grayscale if current display does not support color or with a user selected LUT. See section C.8.13.3.1.2.1.
COLOR_REF Image is intended to be displayed in color using an externally defined Palette Color LUTs, but can be displayed in grayscale if current display does not support color, or with a user selected LUT. I.e., the encoded pixel values are still continuous grayscale values (and not arbitrarily order indices into a lookup table).
MONOCHROME Image is intended to be displayed in grayscale only.

C.8.27.2.4 Bits Allocated, Bits Stored and Samples Per Pixel

For IVOCT images, Bits Allocated (0028,0100), Bits Stored (0028,0101) Samples Per Pixel (0028,0002) are specified to use the following values for Presentation Intent Type (0008,0068) attribute:

Table C.8.27.2-5BITS ALLOCATED/STORED

Presentation Intent Type Bits Allocated / Bits Stored Samples Per Pixel
FOR PRESENTATION 8/8, 16/12 or 16/16 1
FOR PROCESSING 8/8, 16/12 or 16/16 1