Segment Editor help please (thresholds)

Support
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1

Operating system: Windows 8.1
Slicer version: 4.10.1
Expected behavior: Hello all. I am trying to segment CT slices. On the same slice I need to highlight both muscle and fat, which have different thresholds.
Actual behavior: It seems that the “Threshold Range” settings are linked. For example, if I “Add new empty segment” and change the threshold, it changes it for all segments. Likewise, if I “Create new segmentation” and then select the thresholds for each different segmentation, it is still linked (i.e. same threshold). I want to be able to define different thresholds for muscle and fat, and then switch between measuring them. Is this possible?

Thank you, and have a good day!

2

You’re right, currently the threshold setting is global. However if you can use threshold to segment your multiple structures, then there is a good chance that the Grow from seeds can do it too. I strongly suggest trying it.

Please check out this video: https://www.youtube.com/watch?v=8Nbi1Co2rhY

3

If you just want approximate segmentation purely based on Hounsfield units, you can use this short Python script, which creates fat, muscle, bone segments using thresholding and then reports their volumes:

You can find more segmentation scripting examples here: https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#How_to_run_segment_editor_effects_from_a_script

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