DICOM PS3.3 2024e - Information Object Definitions |
---|
Table C.8.28.2-1 specifies the Attributes of the Ophthalmic Thickness Map Module, which describe an Image produced by ophthalmic thickness mapping devices.
Table C.8.28.2-1. Ophthalmic Thickness Map Module Attributes
Describes the type of ophthalmic mapping acquisition device. See Section C.8.28.2.1.3 for further explanation. |
|||
The acquisition method used for obtaining ophthalmic thickness mapping. |
|||
Software algorithm used to provide acquisition method. Required if Acquisition Method Code Sequence (0022,1420) contains an Item with the value of (111923, DCM, "Corneal birefringence compensation") |
|||
>Include Table 10-19 “Algorithm Identification Macro Attributes” |
|||
The date and time that the acquisition of data that resulted in this image started. NoteThe synchronization of this time with an external clock is specified in the Synchronization Module in Acquisition Time Synchronized (0018,1800). |
|||
Image identification characteristics. See Section C.8.28.2.1.1 for specialization. |
|||
Number of samples (planes) in this image. See Section C.7.6.3.1.1 for further explanation. |
|||
Specified the intended interpretation of the pixel data. See Section C.7.6.3.1.2 for further explanation. |
|||
Physical distance in the patient between the center of each pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing in mm. NoteSince a patient's retina is curved, there can be a small error in using Pixel Spacing (0028,0030) for distance measurements in the periphery of the image. See Section 10.7.1.3 for further explanation. |
|||
Ratio of the vertical size and horizontal size of the pixels in the image specified by a pair of integer values where the first value is the vertical pixel size, and the second value is the horizontal pixel size. |
|||
Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See PS3.5 for further explanation. |
|||
Number of bits stored for each pixel sample. Shall be equal to Bits Allocated (0028,0100). |
|||
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 (0028,0101). |
|||
The source of the color information for use during rendering. Enumerated Values:
|
|||
The identifier of the color palette (i.e., an Instance of the Color Palette Storage SOP Class "1.2.840.10008.5.1.4.39.1") for use during rendering. |
|||
Specifies whether an Image has undergone lossy compression (at a point in its lifetime). Enumerated Values: Once this value has been set to "01" it shall not be reset. See Section C.7.6.1.1.5. |
|||
Describes the approximate lossy compression ratio(s) that have been applied to this image. |
|||
A label for the lossy compression method(s) that have been applied to this image. |
|||
Indicates that the image does not contain burned in annotation to identify the patient and date the image was acquired. |
|||
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. |
|||
Laterality of object imaged (as described in Anatomic Region Sequence (0008,2218)) examined. NoteThis Attribute is mandatory, in order to ensure that images may be positioned correctly relative to one another for display. Shall be consistent with any laterality information contained in Primary Anatomic Structure Modifier Sequence (0008,2230), if present. |
|||
The type of ophthalmic thickness map encoded in this SOP Instance. It specifies the meaning of the pixel values. |
|||
Include Table C.7.6.16-12 “Real World Value Mapping Macro Attributes” |
Include if Ophthalmic Thickness Map Type Code Sequence (0022,1436) contains an Item with the value (111930, DCM, "Absolute ophthalmic thickness") or (111932, DCM, "Thickness deviation from normative data"). DCID 4260 “Ophthalmic Mapping Unit for Real World Value Mapping” |
||
Provides a pixel value and the mapping of that pixel value to an associated Coded Concept. Required if Ophthalmic Thickness Map Type Code Sequence (0022,1436) contains an Item with the value (111931, DCM, "Thickness deviation category from normative data"). |
|||
The mapping from Mapped Pixel Value (0022,1452) to an associated Coded Concept. |
|||
Identifies the Externally Sourced Data Set used for mapping values from a normative data base. Required if Ophthalmic Thickness Map Type Code Sequence (0022,1436) contains an Item with the value or (111931, DCM, "Thickness deviation category from normative data") or (111932, DCM, "Thickness deviation from normative data"). May be present otherwise. |
|||
>Include Table 10-22 “Externally-Sourced Data Set Identification Macro Attributes” |
|||
Attributes from the OPT image that provide critical context for the interpretation of this ophthalmic map SOP Instance. Required if Ophthalmic Mapping Device Type (0022,1415) is OCT. |
|||
The inherent limiting resolution in µm for depth of the acquisition equipment for high contrast objects for the data gathering and reconstruction technique chosen. If variable, the value at the center of the scanning volume. |
|||
Maximum distortion in depth direction in % of Depth Spatial Resolution. |
|||
The Image SOP Class/Instance pair of the Image that was used to generate this Image. Required if Ophthalmic Mapping Device Type (0022,1415) is OCT. May be present otherwise. |
|||
>Include Table 10-3 “Image SOP Instance Reference Macro Attributes” |
|||
Describes the purpose for which the reference is made, (i.e., the role the source image or frame(s) played in the generation of this image). Only a single Item shall be included in this Sequence. |
|||
A Sequence that provides reference to a set of SOP Class/Instance pairs identifying images or other composite SOP Instances to plan the acquisition or significant related information. Required if Ophthalmic Photography Reference Image available. May be present otherwise. See Section C.7.6.16.2.5.1 for further explanation. |
|||
>Include Table 10-11 “SOP Instance Reference Macro Attributes” |
|||
Code describing the purpose of the reference to the Instance(s). |
|||
Registration of current Instance to a localizer SOP Instance referenced in Attribute Referenced Instance Sequence (0008,114A). See Section C.8.28.2.1.2 for an example. |
|||
Units of measure for the axes of the registered localizer image. |
|||
Location of the Top Left Hand Corner (TLHC) of the registered localizer in Registered Localizer Units (0022,1466), given as column\row. Column is the horizontal offset and row is the vertical offset. |
|||
Location of the Bottom Right Hand Corner (BRHC) of the registered localizer in which Registered Localizer Units (0022,1466), given as column\row. Column is the horizontal offset and row is the vertical offset. |
|||
Include Table 10-5 “General Anatomy Mandatory Macro Attributes” |
Anatomic Region Sequence (0008,2218) shall be (81745001, SCT, "Eye"). Anatomic Region Modifier Sequence (0008,2220) DCID 244 “Laterality”. Primary Anatomic Structure Sequence (0008,2228) DCID 4266 “Ophthalmic Anatomic Structure Reference Point”. Only a single Item shall be included in this Sequence. |
||
The position of this image on the retina (as defined by a specified nomenclature; the nomenclature is implicit in the code used). Only a single Item is permitted in this Sequence. |
|||
Location of a point in the image identified by an anatomic structure. This is used in ophthalmology for a landmark within a patient's eye. Given as column\row. Column is the horizontal offset and row is the vertical offset. Image relative position specified with sub-pixel resolution such that the origin at the Top Left Hand Corner (TLHC) of the TLHC pixel is 0.0\0.0, the Bottom Right Hand Corner (BRHC) of the TLHC pixel is 1.0\1.0, and the BRHC of the BRHC pixel is Columns\Rows (see Figure C.10.5-1). The values must be within the range 0\0 to Columns\Rows. Required if Primary Anatomic Structure Sequence (0008,2228) contains an Item with the value (67046006, SCT, "Fovea centralis") or (81016008, SCT, "Optic nerve head") or (49755003, SCT, "Lesion") or (111934, DCM, "Disc-Fovea"). |
|||
The definition of the retinal thickness for this image. Required if Attribute Image Type (0008,0008) value 3 is RETINAL_THICK. |
|||
For Ophthalmic Thickness Maps, Image Type (0008,0008) is specified to be Type 1 and uses one of the following Defined Terms for Value 3:
Defined Terms:
Equipment generating an ophthalmic map (OPM) image, may also obtain an accompanying "reference/localizer" image. This "reference/localizer" image serves the purpose of orienting and registering the OPM image to the actual retinal location. For example, a fundus photo may be obtained with ophthalmic tomography (OPT). When the retinal thickness map is generated based on OPT data, the OPM is registered with pixel precision to the fundus photo. This "reference/localizer" image is referenced in the OPM SOP Instance using the Attribute Referenced Instance Sequence (0008,114A).
An example of a "reference/localizer" image and its relationship to an OPM image is shown in Figure C.8.28.2.1-1. Legend: ( A ) a fundus photo is taken as the "reference/localizer" image. The green box indicates the area the OPT scans are obtained. ( B ) The retinal thickness map (OPM object) is overlaid on the "reference/localizer" fundus photo to show the correspondence. These examples could be referenced from different types of SOP Classes, such as Color Softcopy Presentation State Storage (referencing the OP SOP Instance of a fundus photo), True Color Secondary Capture Image Storage, Encapsulated PDF, etc. The Purpose of Reference Code Sequence (0040,A170) code is set to (121311, DCM, "Localizer") for example A. Registration to Localizer Sequence (0022,1465) would be used for example B.
For Ophthalmic Mapping Device Type (0022,1415), Scanning Laser Ophthalmoscopy Tomography (SLO_TOMO) produces a topographical representation of the optic nerve head (ONH) rather than a thickness depiction. However, the topographical depiction can be considered as "thickness" measurements of multiple points of the ONH surface relative to an assigned datum plane. For this reason, the topographical image is included in the Ophthalmic Thickness Map Module.
For Ophthalmic Mapping Device Type (0022,1415), Polarimetric Tomography (POLARIMETRY) produces a thickness depiction based on birefringent phase shifts. This is a thickness measure but does not use typical international system of units such as micrometer, etc. Due to this, the unit of measurement is defined by the implementation, such as 'p-um'.
DICOM PS3.3 2024e - Information Object Definitions |
---|