# Transform CT mask to MR

**URL:** https://discourse.slicer.org/t/transform-ct-mask-to-mr/33063
**Category:** Support
**Tags:** registration
**Created:** [November 27, 2023, 3:46pm UTC](https://discourse.slicer.org/t/transform-ct-mask-to-mr/33063 "2023-11-27T15:46:16Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Walid\_D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/walid_d/32/68477_2.png) [@Walid\_D](https://discourse.slicer.org/u/Walid_D)
#### Post date: [November 27, 2023, 3:46pm UTC](https://discourse.slicer.org/t/transform-ct-mask-to-mr/33063/1 "2023-11-27T15:46:16Z")

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Hey,

I am new to the 3D Slicer, I have CT and MR images of the same patient, the segmentation for the tumor mask is only done on the CT, how can I transform the mask to be used on MR images?

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### Author: ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)
#### Post date: [November 27, 2023, 5:10pm UTC](https://discourse.slicer.org/t/transform-ct-mask-to-mr/33063/2 "2023-11-27T17:10:01Z")

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You have to register the MR to CT rigidly so that it is in the same space as CT. Then you can apply the mask to MR.

You can use Brain Registration or Elastix (separate extension) to do this.

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### Author: ![Walid\_D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/walid_d/32/68477_2.png) [@Walid\_D](https://discourse.slicer.org/u/Walid_D)
#### Post date: [November 29, 2023, 12:45pm UTC](https://discourse.slicer.org/t/transform-ct-mask-to-mr/33063/3 "2023-11-29T12:45:40Z")

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Okay, thank you very much.