Segment Editor help please (thresholds)

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!

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

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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