# Calculating Relative CT Perfusion

**URL:** <https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633>\
**Category:** Support\
**Created:** [July 5, 2017, 8:00pm UTC](https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633 "2017-07-05T20:00:11Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![hph10128](https://avatars.discourse-cdn.com/v4/letter/h/6de8d8/32.png) [@hph10128](https://discourse.slicer.org/u/hph10128)\
**Post date:** [July 5, 2017, 8:00pm UTC](https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633/1 "2017-07-05T20:00:11Z")

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Hi!

I was wondering if there were any modules or extensions that could do a relative perfusion CT calculation. I have an absolute perfusion CBF and CBV and want to calculate relative CBF and CBVs. If not, if any one has any suggestions on how to tackle this in python, it would be greatly appreciated.

Thanks!

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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:** [July 5, 2017, 8:41pm UTC](https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633/2 "2017-07-05T20:41:51Z")

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You can perform computation on voxels by numpy array operations - see [https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Modify\_voxels\_in\_a\_volume](https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Modify_voxels_in_a_volume).

You may also use SimpleFilters module for basic arithmetic operations on volumes (add, subtract, multiply, divide, invert, min, max, …).

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**Author:** ![habril](https://avatars.discourse-cdn.com/v4/letter/h/8797f3/32.png) [@habril](https://discourse.slicer.org/u/habril)\
**Post date:** [September 18, 2018, 10:35am UTC](https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633/3 "2018-09-18T10:35:40Z")

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Hi! Is there a slicer module to calculate perfusion maps on CT images?

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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:** [September 18, 2018, 7:15pm UTC](https://discourse.slicer.org/t/calculating-relative-ct-perfusion/633/4 "2018-09-18T19:15:05Z")

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There are some related modules that you might find usable:

- [https://www.slicer.org/wiki/Documentation/Nightly/Modules/MultiVolumeExplorer](https://www.slicer.org/wiki/Documentation/Nightly/Modules/MultiVolumeExplorer)
- [https://www.slicer.org/wiki/Documentation/Nightly/Modules/DSC\_MRI\_Analysis](https://www.slicer.org/wiki/Documentation/Nightly/Modules/DSC_MRI_Analysis)
- [https://github.com/millerjv/PkModeling](https://github.com/millerjv/PkModeling)