# Volume rendering and multiplanar reconstruction

**URL:** <https://discourse.slicer.org/t/volume-rendering-and-multiplanar-reconstruction/20955>\
**Category:** Support\
**Tags:** segmentation, dicom\
**Created:** [December 7, 2021, 9:42pm UTC](https://discourse.slicer.org/t/volume-rendering-and-multiplanar-reconstruction/20955 "2021-12-07T21:42:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Luna](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/luna/32/11116_2.png) [@Luna](https://discourse.slicer.org/u/Luna)\
**Post date:** [December 7, 2021, 9:42pm UTC](https://discourse.slicer.org/t/volume-rendering-and-multiplanar-reconstruction/20955/1 "2021-12-07T21:42:48Z")

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I am viewing my dicom files in 3D slicer and I notice that the images are stretched out in yz and xz plane, so in all the planes except the original image plane which is xy plane. I tried fiji imageJ as well but my images weren’t stretched here.  
The values in the dicom header for slice thickness and pixel spacing are correct. I have a voxel size of 0.4x0.4x0.4 mm^3, so slice thickness is 0.4 and pixel spacing is [0.4 0.4] in my dicom header. What could have gone wrong? Are there any other attributes that I have to fill in?

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**Author:** ![mikebind](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@mikebind](https://discourse.slicer.org/u/mikebind)\
**Post date:** [December 8, 2021, 11:00pm UTC](https://discourse.slicer.org/t/volume-rendering-and-multiplanar-reconstruction/20955/2 "2021-12-08T23:00:54Z")

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Are you creating the DICOM headers yourself? Slicer does not use the “Slice Thickness” to set the slice spacing, see discussion here:

> [@Slicer loads wrong image spacing](https://discourse.slicer.org/t/slicer-loads-wrong-image-spacing/453/4):
>
> The out of plane spacing is defined by the distance between the ImagePositionPatient of adjacent slices, not by the SliceThickness, which can be different for a variety of reasons.

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**Author:** ![Luna](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/luna/32/11116_2.png) [@Luna](https://discourse.slicer.org/u/Luna)\
**Post date:** [December 9, 2021, 1:45pm UTC](https://discourse.slicer.org/t/volume-rendering-and-multiplanar-reconstruction/20955/4 "2021-12-09T13:45:29Z")

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I created the dicom headers myself.  
I see I defined my ImagePositionPatient incorrectly. Problem is fixed now, thanks a lot!