# How to change segmentation sizes?

**URL:** <https://discourse.slicer.org/t/how-to-change-segmentation-sizes/27920>\
**Category:** Support\
**Tags:** segmentation, dicom, image-dimensions\
**Created:** [February 20, 2023, 6:47am UTC](https://discourse.slicer.org/t/how-to-change-segmentation-sizes/27920 "2023-02-20T06:47:28Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![radiodid](https://avatars.discourse-cdn.com/v4/letter/r/9e8a1a/32.png) [@radiodid](https://discourse.slicer.org/u/radiodid)\
**Post date:** [February 20, 2023, 6:47am UTC](https://discourse.slicer.org/t/how-to-change-segmentation-sizes/27920/1 "2023-02-20T06:47:29Z")

</div>

I’m having trouble with the segmentation size in Slicer. The size of the CT I am working on is 400x400x296, but the segmentation is 252x351x270. I tried to create other segmentations and each time the size is different and does not correspond to the original CT size.  
Visually, segmentation overlaps perfectly with CT, but I also need the segmentation sizes to match the size of the CT.  
Slicer version 5.2.1

Is it possible to change the segmentation size and if so, how?

I will be very grateful for your help.

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/d/9dea616d4d2508d5df54157faf70b9b3dcf51a68.png)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/9/393ba5c93be6f5b1d8f38aff8469309fec172f71.png)