Imager Pixel Spacing Attribute
| Tag | (0018,1164) |
|---|---|
| Type | Conditionally Required (1C) |
| Keyword | ImagerPixelSpacing |
| Value Multiplicity | 2 |
| Value Representation | Decimal String (DS) |
| Example Values |
|
Physical distance measured at the receptor plane of the detector between the centers of each pixel specified by a numeric pair - row spacing value (delimiter) column spacing value in mm. See Section 10.7.1.3 for further explanation of the value order.
The value of this Attribute shall never be adjusted to account for calibration against an object of known size; Pixel Spacing (0028,0030) is specified for that purpose.
It is only allowed to be adjusted to compensate for the change of the Field of View Dimension(s) in Float (0018,9461) Attribute. See Section C.8.19.6.4.1.2
Required if Image Type (0008,0008) Value 1 equals ORIGINAL. May be present otherwise.
Note
These values are the actual pixel spacing distances of the stored pixel values of an image.
Note
Part of the X-Ray Frame Pixel Data Properties Functional Group Macro with usage: M
Section 10.7.1.3
10.7.1.3 Pixel Spacing Value Order and Valid Values
All pixel spacing related Attributes are encoded as the physical distance between the centers of each two-dimensional pixel, specified by two numeric values.
The first value is the row spacing in mm, that is the spacing between the centers of adjacent rows, or vertical spacing.
The second value is the column spacing in mm, that is the spacing between the centers of adjacent columns, or horizontal spacing.
To illustrate, consider the example shown in Figure 10.7.1.3-1.
Figure 10.7.1.3-1. Example of Pixel Spacing Value Order
Pixel Spacing = Row Spacing \ Column Spacing = 0.30\0.25.
All pixel spacing related Attributes shall have positive non-zero values, except when there is only a single row or column or pixel of data present, in which case the corresponding value may be zero.
Note
A single row or column or "pixel" may occur in MR Spectroscopy Instances.
This description applies to:
-
Pixel Spacing (0028,0030)
-
Imager Pixel Spacing (0018,1164)
-
Nominal Scanned Pixel Spacing (0018,2010)
-
Image Plane Pixel Spacing (3002,0011)
-
Compensator Pixel Spacing (300A,00E9)
-
Detector Element Spacing (0018,7022)
-
Presentation Pixel Spacing (0070,0101)
-
Printer Pixel Spacing (2010,0376)
-
Object Pixel Spacing in Center of Beam (0018,9404)
Section C.8.19.6.4.1.2
C.8.19.6.4.1.2 Imager Pixel Spacing
The two values of the Imager Pixel Spacing (0018,1164) Attribute are related to the value(s) of the Field of View Dimension(s) in Float (0018,9461) Attribute in the X-Ray Field of View Functional Group of this frame and the values of the Rows (0028,0010) and Columns (0028,0011) Attributes.
The value(s) of Field of View Dimension(s) in Float (0018,9461) may change on a frame by frame base. The values of the Rows and Columns Attributes are equal for all frames. The relationship between the Attributes depends on the Field of View Shape (0018,1147) Attribute:
If the Field of View Shape (0018,1147) Attribute equals RECTANGLE:
Imager Pixel Spacingrow spacing = FOV Dimensionrow dimension / Rows
Imager Pixel Spacingcolumn spacing = FOV Dimensioncolumn dimension / Columns
If the Field of View Shape (0018,1147) Attribute equals ROUND or HEXAGONAL:
Imager Pixel Spacingrow spacing = FOV Dimensiondiameter / Rows
Imager Pixel Spacingcolumn spacing = FOV Dimensiondiameter / Columns