DICOM PS3.3 2017b - Information Object Definitions

C.8.17.16 Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Image Module
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#### C.8.17.16 Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Image Module

Table C.8.17.16-1 specifies the Attributes that describe the Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Image Module.

Table C.8.17.16-1. Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Image Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Image Type | (0008,0008) | 1 | Image identification characteristics. Enumerated Values for Value 1: ORIGINAL Enumerated Values for Value 2: PRIMARY
Instance Number | (0020,0013) | 1 | A number that identifies this SOP Instance.
Content Time | (0008,0033) | 1 | The time the image pixel data creation started.
Content Date | (0008,0023) | 1 | The date the image pixel data creation started.
Bits Allocated | (0028,0100) | 1 | Number of bits allocated for each pixel sample. Enumerated Values: 8 16
Bits Stored | (0028,0101) | 1 | Number of bits stored for each pixel sample.
High Bit | (0028,0102) | 1 | Most significant bit for pixel sample data. Shall be one less than the value in Bits Stored (0028,0101).
Samples per Pixel | (0028,0002) | 1 | Number of samples (planes) in this image. Enumerated Values: 1
Photometric Interpretation | (0028,0004) | 1 | Specifies the intended interpretation of the pixel data. Enumerated Value: MONOCHOME2
Pixel Representation | (0028,0103) | 1 | Data representation of pixel samples. Enumerated Values: 1
Presentation LUT Shape | (2050,0020) | 1 | Specifies an identity transformation for the Presentation LUT such that the output of all grayscale transformations are defined to be in 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) , or is derived from lossy compressed images. 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.8.32.2.1 and 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 present in the source images or this IOD instance has been compressed.
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 present in the source images or this IOD instance has been compressed. See Section C.8.32.2.1.
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) | 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: YES NO
Acquisition Method Algorithm Sequence | (0022,1423) | 1 | Software algorithm used by the acquisition method. Only a single Item shall be included in this Sequence.
>Include Table 10-19 “Algorithm Identification Macro Attributes” | For Algorithm Family Code Sequence (0066,002F) Baseline CID 4270 “OCT-A Processing Algorithm Families”.
OCT B-scan Analysis Acquisition Parameters Sequence | (0022,1640) | 1 | Conveys raw data parameters captured during the B-scan acquisition process. One or more Items are permitted in this Sequence. More than one Item indicates that multiple scan patterns have been used to acquire the raw data. See Section C.8.17.16.2 for further explanation.
>Scan Pattern Type Code Sequence | (0022,1618) | 1 | The scan pattern type used to generate this SOP Instance. Only a single Item shall be included in this Sequence.
>>Include Table 8.8-1 “Code Sequence Macro Attributes” | Defined CID CID 4272 “Opt Scan Pattern Types”
>Number Of B-scans Per Frame | (0022,1642) | 1 | The number of B-scans performed at the same spatial location (B-scan slab). See Section C.8.17.16.2 for further explanation.
>B-scan Slab Thickness | (0022,1643) | 1 | Nominal thickness of each B-scan slab, in mm. See Section C.8.17.16.2 for further explanation.
>Distance Between B-scan Slabs | (0022,1644) | 1 | Nominal distance between adjacent B-scan slabs, in mm. See Section C.8.17.16.2 for further explanation.
>B-scan Cycle Time | (0022,1645) | 1C | Nominal time (in msec) between individual B-scans. See Section C.8.17.16.1.1 for further explanation. Required if B-scan Cycle Time Vector (0022,1646) is absent.
>B-scan Cycle Time Vector | (0022,1646) | 1C | An array that contains the real time increments (in msec) between B-scans. See Section C.8.17.16.1.1 for further explanation. Required if B-scan Cycle Time (0022,1645) is absent. ### Note scan time + latency between B-scans
>A-scan Rate | (0022,1649) | 3 | Frequency, in kHz, of the A-scan used to acquire the raw image data.
>B-scan Rate | (0022,1650) | 3 | Frequency, in Hz, of the B-scan used to acquire the raw image data.
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

##### C.8.17.16.1 Ophthalmic Optical Coherence Tomography B-scan Volume Analysis Image Module Attribute Descriptions

###### C.8.17.16.1.1 B-scan Cycle Time and B-scan Cycle Time Vector

The B-scan Cycle Time (0022,1645) is the nominal scan time (in milliseconds) plus the latency between the individual repeats of the B-scan at the same location. The B-scan Cycle Time Vector can be used if the time for the repeats are not uniform. Either the B-scan Cycle Time (0022,1645) or the B-scan Cycle Time Vector (0022,1646) are required.

B-scan Cycle Time shall be used in the following manner to calculate 'the relative time' for each B-scan:

- B-scan Cycle 'Relative Time' (n) = B-scan Cycle Delay + B-scan Cycle Time * (n-1)

where:

- n = number of B-scan cycles within the frame and the first B-scan number is one

### Note

When there is only one B-scan present, B-scan Cycle Time (0022,1645) may have either a value of 0, or a nominal value that would apply if there were multiple B-scans.

B-scan Cycle Time Vector (0022,1646) is an array that contains the time increments (in milliseconds) between the nth B-scan cycle and the previous B-scan cycle for a frame. The first B-scan cycle always has a time increment of 0. The B-scan Cycle Time Vector shall be used in the following manner to calculate 'relative time' T(n)for B-scan Cycle n:

where Δti is the ith B-scan Cycle Time Vector component.

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DICOM PS3.3 2017b - Information Object Definitions