# Quantification based on centerline curve or centerline model?

**URL:** <https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676>\
**Category:** Support\
**Tags:** quantitative, vmtk, vmtk-centerline\
**Created:** [October 13, 2022, 11:43am UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676 "2022-10-13T11:43:58Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![JBierens](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jbierens/32/16926_2.png) [@JBierens](https://discourse.slicer.org/u/JBierens)\
**Post date:** [October 13, 2022, 11:43am UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676/1 "2022-10-13T11:43:59Z")

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I am wondering if the Centerline quantification table is based on the properties of the centerline model or centerline curves. Sometimes when I extract the centerline, I only get one centerline curve, that is only covering a small part of the model. Other times I get multiple centerline curves that cover the full centerline model. Also, what could be a reason I only get one centerline curve sometimes?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/c/a/ca090cd418a6f023e0b2f2e1f78ebbe435e33d59.png)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/1/7128d7082658d2e406f6b44821bb9c225e92a42f.png)

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**Author:** ![JBierens](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jbierens/32/16926_2.png) [@JBierens](https://discourse.slicer.org/u/JBierens)\
**Post date:** [October 18, 2022, 11:18am UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676/2 "2022-10-18T11:18:24Z")

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Could someone please help me?

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**Author:** ![JBierens](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jbierens/32/16926_2.png) [@JBierens](https://discourse.slicer.org/u/JBierens)\
**Post date:** [October 18, 2022, 11:41am UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676/3 "2022-10-18T11:41:31Z")

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Ive understood by now that the geometrical properties are computed for each branch, so I think that means that the CellIDs in the table represent every centerline curve (can someone please confirm this?).

Still I am wondering why I get a table with multiple CellID lines while I only get one centerline curve sometimes. Does someone know why?

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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 18, 2022, 4:32pm UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676/4 "2022-10-18T16:32:48Z")

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To create curves, we need to interpret the list of branches in the centerline tree. This is implemented by using vtkvmtkCenterlineBranchExtractor followed by vtkvmtkMergeCenterlines - see details [here](https://github.com/vmtk/SlicerExtension-VMTK/blob/913e0f9a7a4a085b80d877ff3730e98374b9ee98/ExtractCenterline/ExtractCenterline.py#L834-L856). During this process, cells of the model are split and merged so that in the end one curve always corresponds to one branch.

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**Author:** ![JBierens](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jbierens/32/16926_2.png) [@JBierens](https://discourse.slicer.org/u/JBierens)\
**Post date:** [October 19, 2022, 7:59am UTC](https://discourse.slicer.org/t/quantification-based-on-centerline-curve-or-centerline-model/25676/5 "2022-10-19T07:59:53Z")

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Thank you for your answer. Still, it is not clear to me why 3D slicer sometimes shows me only one curve, that does not cover my model (see the second image in the original post). Do you know why or how I can solve this?