# How to calculate the internal cranial volume (space occupied by the brain) in 3D Slicer

**URL:** <https://discourse.slicer.org/t/how-to-calculate-the-internal-cranial-volume-space-occupied-by-the-brain-in-3d-slicer/44955>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [November 3, 2025, 9:45pm UTC](https://discourse.slicer.org/t/how-to-calculate-the-internal-cranial-volume-space-occupied-by-the-brain-in-3d-slicer/44955 "2025-11-03T21:45:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Luz\_Velasco](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/luz_velasco/32/78226_2.png) [@Luz\_Velasco](https://discourse.slicer.org/u/Luz_Velasco)\
**Post date:** [November 3, 2025, 9:45pm UTC](https://discourse.slicer.org/t/how-to-calculate-the-internal-cranial-volume-space-occupied-by-the-brain-in-3d-slicer/44955/1 "2025-11-03T21:45:14Z")

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Hello everyone,

I have a 3D CT scan of a skull (without the brain visible), and I would like to calculate the _internal cranial volume_ — that is, the volume corresponding to the space where the brain would normally be located inside the skull.

Is there any tool or recommended workflow in 3D Slicer that allows me to compute this internal volume?  
For example, is it possible to segment the inner surface of the cranial cavity and then calculate the enclosed volume?

Any guidance or suggested modules (e.g., Segment Editor, Segment Statistics, or other approaches) would be greatly appreciated.

Thank you very much for your help!

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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 4, 2025, 6:12am UTC](https://discourse.slicer.org/t/how-to-calculate-the-internal-cranial-volume-space-occupied-by-the-brain-in-3d-slicer/44955/2 "2025-11-04T06:12:26Z")

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You can use **SurfaceWrapSolidify** extension to fill the cranial cavity, and extra an endocast. Then you can use the `SegmentStatistics` module to calculate the volume of the endocast.

There is also a SlicerMorph module called SegmentEndocranium, which under the hood uses the SurfaceWrapSolidify.

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**Author:** ![philippepellerin](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/philippepellerin/32/16062_2.png) [@philippepellerin](https://discourse.slicer.org/u/philippepellerin)\
**Post date:** [November 5, 2025, 11:03am UTC](https://discourse.slicer.org/t/how-to-calculate-the-internal-cranial-volume-space-occupied-by-the-brain-in-3d-slicer/44955/3 "2025-11-05T11:03:22Z")

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This is the right tool, indeed, but to have an accurate result, you must segment the skull itself, remove the spine, and have the setting like that.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/9/1934264d23bb3c65231e50d7ca623969ca1298f8.png)