# Surface/Edge Segmentation for White Matter

**URL:** <https://discourse.slicer.org/t/surface-edge-segmentation-for-white-matter/4339>\
**Category:** Support\
**Created:** [October 10, 2018, 2:11am UTC](https://discourse.slicer.org/t/surface-edge-segmentation-for-white-matter/4339 "2018-10-10T02:11:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Hassan\_Farhat](https://avatars.discourse-cdn.com/v4/letter/h/ccd318/32.png) [@Hassan\_Farhat](https://discourse.slicer.org/u/Hassan_Farhat)\
**Post date:** [October 10, 2018, 2:11am UTC](https://discourse.slicer.org/t/surface-edge-segmentation-for-white-matter/4339/1 "2018-10-10T02:11:08Z")

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Dear Community,

I’m working on segmented Brain MRI images (GM, WM, CSF), I would like to extract a continuous boundary for White matter to be able to test specific algorithms. Since WM maps are probability maps, I have difficulty to extract a linked continuous boundary. I have created as well some phantoms to help test my boundary extraction algorithms. Is there any tools in SLICER that can help in extracting a thin (1 voxel wide) 3D WM boundary?

Best Regards  
Hassan Farhat

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [October 10, 2018, 1:10pm UTC](https://discourse.slicer.org/t/surface-edge-segmentation-for-white-matter/4339/2 "2018-10-10T13:10:12Z")

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You can threshold the probability map to get a thick boundary and then thin it to a single-voxel surface using “Extract skeleton” module (Skeleton type: 2D; Do not prune branches: enabled).