Te Usage - GE Definium 5000 Operator's Manual

TE Usage

Over-penetrated Regions
An over-penetrated region in an image results from x-rays passing through a relatively less dense region
of the anatomy such as soft tissue (skin edge).
Over-penetrated regions of an image appear darker with reduced contrast. Using TE, the contrast in such
regions can be enhanced to improve visualization of soft-tissue. TE can also be used to enhance vessel
contrast in lungs. In Figure 10-26, the skin edge around the neck is more clearly defined with TE.
Under-penetrated Regions
An under-penetrated region in an image results from insufficient x-rays passing through relatively dense
anatomical regions. For example, anatomy containing dense tissue (abdomen) and bone (ankles/wrists/
shoulders) result in under-penetrated images.
Under-penetrated regions of an image such as the cervical and thoracic spine appear white- white spine
obscured by the overlaying anatomy like the white shoulders. Using TE, the overlaying anatomy can be
made grayer making the underlying spine more visible (Figure 10-26). A hand image can similarly be
displayed with improved bone contrast. This makes TE an invaluable tool in visualizing the entire bone
field.
Figure 10-26 Comparison with and without Tissue Equalization
TE Parameters
TE uses the information in the image to improve visualization. Two user-defined parameters; AREA and
STRENGTH; control the extent and amount of TE that is applied to the image. There is an AREA and
STRENGTH parameter for over-penetrated regions and an AREA and STRENGTH parameter for under-
penetrated regions.
Area
The AREA parameter defines the extent of application of the TE algorithm to the image. Increasing AREA
increases the number of image pixels to which TE is applied. For example, in Figure 10-27, setting the
AREA to 30% for under-penetrated region uses the pixels within the dotted ROI. Increasing AREA to 60%
increases the number of pixels where TE is applied, as indicated by the solid ROI.
Definium 5000 X-Ray System
Operator Manual
5197809-1EN Rev. 4 (13 February 2008)
© 2008 General Electric Company. All rights reserved.
Chapter 10: Set Preferences
10-38