Reconstruction Diameter Attribute
| Tag | (0018,1100) |
|---|---|
| Type | Conditionally Required (1C) |
| Keyword | ReconstructionDiameter |
| Value Multiplicity | 1 |
| Value Representation | Decimal String (DS) |
| Example Values |
|
The diameter in mm of the region from which data were used in creating the reconstruction of the image. Data may exist outside this region and portions of the patient may exist outside this region. See Section C.8.15.3.6.1.
The diameter defines a circular region that is entirely contained within the encoded Pixel Data (7FE0,0010), unless the encoded image has been cropped after reconstruction.
Note
If not cropped or padded, for square images with square pixels, both values of Pixel Spacing (0028,0030) will be equal and equal to Reconstruction Diameter (0018,1100) / Rows (0028,0010) and Reconstruction Diameter (0018,1100) / Columns (0028,0011).
Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Reconstruction Field of View (0018,9317) is not present.
Otherwise may be present if Frame Type (0008,9007) Value 1 of this frame is DERIVED and Reconstruction Field of View (0018,9317) is not present.
Note
Part of the CT Reconstruction Functional Group Macro with usage: C
Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Acquisition Type (0018,9302) is other than CONSTANT_ANGLE, may be present otherwise.
Section C.8.15.3.6.1
C.8.15.3.6.1 Relationships Between CT Geometric Attributes (Informative)
In Figure C.8-19 the relationship of the Geometric Attributes within the CT Geometry and CT Reconstruction Functional Groups is shown. In this example, the Pixel Data is shown encoding the entire reconstructed region with no outside padding or clipping, and the reconstructed region is illustrated as being square, i.e., the value of Reconstruction Diameter would be the same as both values of Reconstruction Field of View, whichever Attribute is present. Figure C.8-19, viewed from the front of the gantry (where the table enters the gantry), is informative only and is not meant to represent a standardization of an equipment-based Frame of Reference.
Figure C.8-19. Geometry of CT Acquisition System