The Image Subtraction mode is designed to subtract one volume from another
Applicable only for CT, MRI, and PET studies
Entering the Mode
Click on the tool panel or
Hover the mouse over the series/image thumbnail in the Preview Bar that you want to subtract
Left-click the "More" button
A menu will appear
Left-click on the "Subtraction" item:
In both cases, a window will appear
The further steps are similar to those described in the "Fusion Mode" chapter
If the button on the tool panel was selected
Hold the left mouse button over the series in the Ribbon you want to "subtract" and drag it to the empty field
When adding a series from the Preview Bar by selecting the Subtraction item, the series is added automatically
Editing Source Data Before Processing
The double arrow changes the layer order
Color palette selection applies only to the overlaid layer
For subtraction mode, the grayscale palette is preferred
Click the OK button to enter Subtraction mode:
Editing Source Data After Processing
Left-click the Subtraction button in the upper left corner of the series header
In the menu that appears, left-clicking the "Settings" item brings up the same window as when entering the mode
Change the layer order and palette if necessary
Left-click the white rectangle in the upper left corner of the series header, to the right of the Subtraction button, to edit only the top layer
Hold the left mouse button to change brightness/contrast, right button to shift the top layer relative to the bottom one
Left-click the white rectangle again to lock the layers
Note: Layer alignment by size is performed automatically by the program and cannot be edited
Saving Subtraction Mode Results
To save all images:
Click the button in the upper left corner of the series
In the menu that appears, select the bottom item - "Save resulting series", and click it
The entire resulting series will be saved and placed at the end of the study in the Preview Bar
To save a single image from the mode:
Scroll through the frames to the required one
Click on the tool panel
- will save only the active projection or
- will save the entire screen image to a user series
Exiting Subtraction Mode
Click the "Exit mode" item in the Subtraction menu
See also
- will save only the active projection or
- will save the entire screen image to a user series