# Circular ROI in MRI image

**URL:** <https://discourse.slicer.org/t/circular-roi-in-mri-image/26582>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [December 5, 2022, 5:35pm UTC](https://discourse.slicer.org/t/circular-roi-in-mri-image/26582 "2022-12-05T17:35:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![hanan](https://avatars.discourse-cdn.com/v4/letter/h/b77776/32.png) [@hanan](https://discourse.slicer.org/u/hanan)\
**Post date:** [December 5, 2022, 5:35pm UTC](https://discourse.slicer.org/t/circular-roi-in-mri-image/26582/1 "2022-12-05T17:35:33Z")

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![Capture.PNG](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/2/12f6293fcbc6828f6ff373615784d1adf1e69e40.jpeg)  
Hello,  
I do the segmentations on the MRI image but as shown in the figure I can’t get circular ROI. I use Segment Editor to segment. Is there any other method that gives circular shaped ROI?  
Thanks in advance

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [December 5, 2022, 7:38pm UTC](https://discourse.slicer.org/t/circular-roi-in-mri-image/26582/2 "2022-12-05T19:38:18Z")

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Binary labelmaps approximate the shape at a given resolution. When you build a 3D representation it will look more spherical. If it’s not high enough resolution you can increase the resolution of the segmentation ([Segment editor — 3D Slicer documentation](https://slicer.readthedocs.io/en/latest/user_guide/modules/segmenteditor.html#segmentation-is-not-accurate-enough)). If you really want precise spheres or circles you could try some kind of parametric technique but usually that isn’t the best approach.

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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:** [December 5, 2022, 8:42pm UTC](https://discourse.slicer.org/t/circular-roi-in-mri-image/26582/3 "2022-12-05T20:42:59Z")

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Also note that you can segment these spheres or tubes fully automatically by using

- Threshold effect, followed by
- Islands effect → Split islands to segments

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**Author:** ![hanan](https://avatars.discourse-cdn.com/v4/letter/h/b77776/32.png) [@hanan](https://discourse.slicer.org/u/hanan)\
**Post date:** [December 6, 2022, 4:52pm UTC](https://discourse.slicer.org/t/circular-roi-in-mri-image/26582/4 "2022-12-06T16:52:24Z")

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Thanks for your help!