# Bias estimation of Volume changes

**URL:** <https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111>\
**Category:** Development\
**Tags:** segmentation\
**Created:** [December 17, 2020, 1:18pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111 "2020-12-17T13:18:17Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ash\_Alarfaj](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ash_alarfaj/32/3327_2.png) [@Ash\_Alarfaj](https://discourse.slicer.org/u/Ash_Alarfaj)\
**Post date:** [December 17, 2020, 1:18pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111/1 "2020-12-17T13:18:17Z")

</div>

Hello  
I’ve used slicer for measuring muscle volume change offer 4-time points threshold effect. I’ve compared two different MRI sequences but covered a quite similar area. The volume changes are different between the two sequences. Do you have any explanation or studies discuss this issue?

---

<div class="post-metadata">

**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:** [December 17, 2020, 10:16pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111/2 "2020-12-17T22:16:45Z")

</div>

What is the percentage difference?  
Can you attach a few screenshots that show the different segmentations?

---

<div class="post-metadata">

**Author:** ![Ash\_Alarfaj](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ash_alarfaj/32/3327_2.png) [@Ash\_Alarfaj](https://discourse.slicer.org/u/Ash_Alarfaj)\
**Post date:** [December 23, 2020, 3:43pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111/3 "2020-12-23T15:43:53Z")

</div>

![Screenshot.C4.V1.R](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/0/5082c302142ade3dcc41650841e22ec9e1da33eb.png)  
These are from the same subject. actually, I’ve run measurements for 8 subjects two thighs the results not consistent. even the percentage change between visits, as the scan repeated 3 times after specific intervention.  
the 2nd issue I’ve found slicer 10.2 the best. the others 10.0 and 11 versions have not worked perfectly.

thanks

---

<div class="post-metadata">

**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:** [December 23, 2020, 3:47pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111/4 "2020-12-23T15:47:09Z")

</div>

> [@Ash\_Alarfaj](#):
>
> I’ve run measurements for 8 subjects two thighs the results not consistent.

What are the the total volumes that you measure on the different images? What is the voxel spacing of your volumes (you can see that in Volumes module / Volume information section)?

> [@Ash\_Alarfaj](#):
>
> the 2nd issue I’ve found slicer 10.2 the best. the others 10.0 and 11 versions have not worked perfectly

In general, newer Slicer versions work better. If you encounter any specific issues then let us know.

---

<div class="post-metadata">

**Author:** ![Ash\_Alarfaj](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ash_alarfaj/32/3327_2.png) [@Ash\_Alarfaj](https://discourse.slicer.org/u/Ash_Alarfaj)\
**Post date:** [December 23, 2020, 9:32pm UTC](https://discourse.slicer.org/t/bias-estimation-of-volume-changes/15111/5 "2020-12-23T21:32:17Z")

</div>

Hello  
the total volume I’ve used is the last column (O) volume(3) as I’ve run a test on phantom and it was the most correct one.

please find the dimensions of the images as screenshots. They are different but I thought the change of muscle volume in both sequences would be similar but it is not.

- yes I’ve found the contrast adjust effect it is changed in the new slicer. perfect

Thanks a lot, Mr Andras for your support

 ![Screenshot.volum dimension.T1.png](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/3/f3ba1296a1a236ec41f44de56b6cc974b3fd3b80.png)

 ![Screenshot.volum dimensions.wats.png](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/b/a/baf06faccb0d5d5e1d7cf26bf90e9505af6ab731.png)