C.8.27.6.3 Intravascular OCT Frame Content Macro

C.8.27.6.3 Intravascular OCT Frame Content Macro (Current)
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Table C.8.27.6.3-1 specifies the Attributes of the Intravascular OCT Frame Content Functional Group.

Table C.8.27.6.3-1. Intravascular OCT Frame Content Macro Attributes

Attribute Name	Tag	Type	Attribute Description
Intravascular OCT Frame Content Sequence	(0052,0029)	1	A Sequence that describes a general description of this image or frame. Only a single Item shall be included in this Sequence.
>OCT Z Offset Correction	(0052,0030)	1	The amount to shift the frame along the axial direction, in pixels, to correct for interferometer path-length mismatch. See Section C.8.27.6.3.1 for further explanation.
>Seam Line Index	(0052,0036)	1	The A-line number (zero index) that coincides with the seam line as indicated with the First A-line Location (0052,0034) Attribute.
>Number of Padded A-lines	(0052,0038)	1C	The number of padded A-lines contained in the FOR PROCESSING image frame. Required if the FOR PROCESSING image contains padded A-lines. See Section C.8.27.6.3.2 for further explanation.

C.8.27.6.3.1 OCT Z Offset Correction

OCT Z Offset Correction (0052,0030) specifies the number of pixels to shift the A-lines of the frame to correct for the path length difference between the OCT Sample arm and Reference arm (in air). A positive value of Z Offset correction means pixels are shifted further away from the catheter optics. A negative value of Z Offset correction means pixels are shifted closer to the catheter optics. See Figure C.8.27-2

Figure C.8.27-2. OCT Z Offset Correction Example

C.8.27.6.3.2 A-line Padding

Padded A-lines shall not be used in FOR PRESENTATION frames. Padded A-lines shall only be encoded in the high order rows of the FOR PROCESSING frame and shall be contiguous. Padded A-lines may contain arbitrary pixel values.

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C.8.27.6.2 Intravascular Frame Content Macro	Home	C.8.28 Ophthalmic Thickness Map Modules