#  Registration MR and CT images

**URL:** <https://discourse.slicer.org/t/registration-mr-and-ct-images/17066>\
**Category:** Support\
**Tags:** registration, mri\
**Created:** [April 13, 2021, 3:36pm UTC](https://discourse.slicer.org/t/registration-mr-and-ct-images/17066 "2021-04-13T15:36:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![berileker](https://avatars.discourse-cdn.com/v4/letter/b/cc9497/32.png) [@berileker](https://discourse.slicer.org/u/berileker)\
**Post date:** [April 13, 2021, 3:36pm UTC](https://discourse.slicer.org/t/registration-mr-and-ct-images/17066/1 "2021-04-13T15:36:41Z")

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Operating system:registraiton  
Slicer version:4.11.20200930  
Expected behavior:Registration MRI and CT images without any trouble  
Actual behavior:Since the CT image I have is cut from the lower part of the noise,many structures in the MR image do not correspond to the CT,so the registration process cannot be performed completely. What I should do? What do you suggest?

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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:** [April 14, 2021, 4:44am UTC](https://discourse.slicer.org/t/registration-mr-and-ct-images/17066/2 "2021-04-14T04:44:25Z")

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In general, you need to crop the two input volumes to approximately the same region before attempting to register. The computed transform can then be applied to the entire non-cropped volume.

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**Author:** ![berileker](https://avatars.discourse-cdn.com/v4/letter/b/cc9497/32.png) [@berileker](https://discourse.slicer.org/u/berileker)\
**Post date:** [May 11, 2021, 10:37pm UTC](https://discourse.slicer.org/t/registration-mr-and-ct-images/17066/3 "2021-05-11T22:37:48Z")

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So how can I make this clipping process the most simple and convenient?

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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:** [May 12, 2021, 12:07am UTC](https://discourse.slicer.org/t/registration-mr-and-ct-images/17066/4 "2021-05-12T00:07:24Z")

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For cropping volumes, the easiest is to use Crop volume module.