# Segment statistics

**URL:** <https://discourse.slicer.org/t/segment-statistics/7303>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [June 25, 2019, 12:08pm UTC](https://discourse.slicer.org/t/segment-statistics/7303 "2019-06-25T12:08:36Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![persst](https://avatars.discourse-cdn.com/v4/letter/p/46a35a/32.png) [@persst](https://discourse.slicer.org/u/persst)\
**Post date:** [June 25, 2019, 12:08pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/1 "2019-06-25T12:08:36Z")

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Hi!

I have a question regarding the module Segment Statistics. After applying Segement Statistics in 3DSlicer 4.9, 3DSlicer displays two different volumes, volume (1) and (2).

Please find the attached table here:

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/0/5/05652fc5faf9880b496789931708c7ece1cf41f8.png)

What is the difference between these volumes?

Thanks!

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**Author:** ![jamesobutler](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jamesobutler/32/7511_2.png) [@jamesobutler](https://discourse.slicer.org/u/jamesobutler)\
**Post date:** [June 25, 2019, 2:02pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/2 "2019-06-25T14:02:53Z")

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See some information from the following thread:

> [@How to measure 3D volume's dimensions?](https://discourse.slicer.org/t/how-to-measure-3d-volumes-dimensions/1170/8):
>
> There are several ways of computing these metrics. The main difference is what is the representation used (surface or volumetric) and if the entire segment is used or only the part that overlaps with the selected scalar volume. Also, is there a way to compute maximum/minimum 3D diameter with any of the statistics modules? Currently diameter computation is not offered by any of the Segment Statistics plugins. SimpleITK’s LabelShapeStatisticsImageFilter can compute many kind of diameters and…

> It does not matter which method you use (the difference is less than 1%), just choose one and use always that. If you primarily work with labelmaps (and use 3D surface for visualization only) then you may prefer labelmap based method; if you mainly work with surfaces then you may choose the volume computed from the generated surface.

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**Author:** ![doc-xie](https://avatars.discourse-cdn.com/v4/letter/d/c77e96/32.png) [@doc-xie](https://discourse.slicer.org/u/doc-xie)\
**Post date:** [June 26, 2019, 1:49pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/3 "2019-06-26T13:49:11Z")

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Hi James Butler,  
The difference between the two volumes is 30% and more than 1%. So which one is the actual volume of the infarction?  
Thanks,  
Xie

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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:** [June 26, 2019, 2:44pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/4 "2019-06-26T14:44:42Z")

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There is also a difference in what volume the statistics is computed on. For example, closed surface statistics plugin reports the entire segment volume; Scalar volume statistics reports only the part that overlaps with the selected “Scalar volume”.

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**Author:** ![manjula](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/manjula/32/80981_2.png) [@manjula](https://discourse.slicer.org/u/manjula)\
**Post date:** [January 23, 2020, 6:53pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/5 "2020-01-23T18:53:41Z")

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> [@lassoan](#):
>
> atistics plugin reports the entire segment volu

Dear Prof Lasso,

To calculate the volume of bone and lacuna space percentage,

for example if segment 1st segment with 700 - 1000 HU and the next segment on the exact same region with 300-500 HU and if i want to measure the volume of 1st and 2nd segment in a CT which volume should i use ?

Label map or the closed surface statistics volume would be better ?

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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:** [January 30, 2020, 3:54pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/6 "2020-01-30T15:54:20Z")

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It should not matter much as long as you consistently use the same method. If your workflow is primarily uses labelmaps then use labelmap-based metrics, if you mainly work with surface meshes then it may make more sense to use metrics computed from closed surface representation.

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**Author:** ![manjula](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/manjula/32/80981_2.png) [@manjula](https://discourse.slicer.org/u/manjula)\
**Post date:** [January 30, 2020, 9:17pm UTC](https://discourse.slicer.org/t/segment-statistics/7303/7 "2020-01-30T21:17:25Z")

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Thank you much appreciated !