# Problems when segmenting blood vessels using VMTK (threshold)

**URL:** https://discourse.slicer.org/t/problems-when-segmenting-blood-vessels-using-vmtk-threshold/8536
**Category:** Support
**Tags:** segmentation
**Created:** [September 23, 2019, 2:35pm UTC](https://discourse.slicer.org/t/problems-when-segmenting-blood-vessels-using-vmtk-threshold/8536 "2019-09-23T14:35:35Z")
**Posts on this page:** 1
**Showing post:** 9

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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 2, 2019, 1:21am UTC](https://discourse.slicer.org/t/problems-when-segmenting-blood-vessels-using-vmtk-threshold/8536/9 "2019-10-02T01:21:28Z")

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This looks good! The only thing you missed is setting sufficiently fine resolution for your segmentation. Spacing of the segmentation’s binary labelmap representation should be at least 1/5th but preferably 1/10th of the smallest vessel diameter. See [here](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269/2) how to change the resolution of a segmentation node.

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