DICOM PS3.3 2024d - Information Object Definitions

C.8.17.7 Ophthalmic Tomography Image Module

Table C.8.17.7-1 specifies the Attributes of the Ophthalmic Tomography Image Module, which describe an Image produced by Ophthalmic Tomography imaging modalities.

Table C.8.17.7-1. Ophthalmic Tomography Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Ophthalmic Volumetric Properties Flag

(0022,1622)

1C

Whether this SOP Instance is suitable for OCT volumetric processing. See Section C.8.17.7.1 for further explanation.

Required if this SOP Instance is suitable for OCT volumetric processing. May be present otherwise.

Enumerated Values:

YES

NO

Image Type

(0008,0008)

1

Image identification characteristics. See Section C.7.6.1.1.2 for Enumerated Values and Defined Terms and further explanation.

Samples Per Pixel

(0028,0002)

1

Number of samples (planes) in this image. See Section C.7.6.3.1.1 for further explanation.

Enumerated Values:

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 Ophthalmic 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 that resulted in this image.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data.

Enumerated Values:

MONOCHROME2

Pixel Representation

(0028,0103)

1

Data representation of pixel samples.

Enumerated Values:

0

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated.

Enumerated Values:

8

16

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample. Each sample shall have the same number of bits stored.

Enumerated Values:

8

12

16

High Bit

(0028,0102)

1

Most significant bit for pixel sample data. Each sample shall have the same high bit.

High Bit (0028,0102) shall be one less than Bits Stored.

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.

Lossy Image Compression

(0028,2110)

1

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.

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".

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 Values:

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.

Concatenation Frame Offset Number

(0020,9228)

1

Offset of the first frame in a multi-frame image of a concatenation.

Enumerated Values:

0

In-concatenation Number

(0020,9162)

1

Identifier for one SOP Instance belonging to a concatenation.

Enumerated Values:

1

In-concatenation Total Number

(0020,9163)

1

The number of SOP Instances sharing the same Concatenation UID (0020,9161).

See Section C.8.17.16.3 for further explanation.

Enumerated Values:

1

Image Comments

(0020,4000)

3

User-defined comments about the image.


The value constraints on Concatenation Frame Offset Number (0020,9228), In-concatenation Number (0020,9162), and In-concatenation Total Number (0020,9163) have the effect of preventing the use of concatenations.

C.8.17.7.1 Ophthalmic Volumetric Properties and Frame of Reference

The Attribute Ophthalmic Volumetric Properties Flag (0022,1622) is YES when the Ophthalmic Tomography Image Storage SOP Instance encodes volumetric spatial information (e.g. Frame of Reference, Pixel Measures, Plane Orientation, Plane Position, etc.). For example, ophthalmic tomography volumetric information is required when implementations encode Surface Segmentation SOP Instance(s) (e.g., surface segmentation is applied to the structural OCT volume to delineate the anatomical boundaries) and/or an Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Storage SOP Instance (e.g., angiographic (blood flow) volume information) based upon the volumetric Ophthalmic Tomography Image Storage SOP Instance.

The coordinate system of the Ophthalmic Tomography Image is typically deformed from the nominal Patient-based Coordinate System. The Frame of Reference UID (0020,0052) identifies volumetric space as represented by the voxels of the SOP Instance, including any such deformations. The values of the Attributes of the Pixel Measures, Plane Position (Patient), and Plane Orientation (Patient) Functional Groups are nominal, and should not be assumed to be usable for computing real-world locations in the patient.

Note

The coordinate system used in an Ophthalmic Tomography Image Storage SOP Instance may treat the curved retinal surface as if it were a flat coronal plane, and the column, row, and slice spacing may vary across the imaged volume.

DICOM PS3.3 2024d - Information Object Definitions