# Question regarding converting a model back to a segmentation node

**URL:** <https://discourse.slicer.org/t/question-regarding-converting-a-model-back-to-a-segmentation-node/24974>\
**Category:** Support\
**Created:** [August 29, 2022, 9:38am UTC](https://discourse.slicer.org/t/question-regarding-converting-a-model-back-to-a-segmentation-node/24974 "2022-08-29T09:38:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jegberink](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jegberink/32/16031_2.png) [@jegberink](https://discourse.slicer.org/u/jegberink)\
**Post date:** [August 29, 2022, 9:38am UTC](https://discourse.slicer.org/t/question-regarding-converting-a-model-back-to-a-segmentation-node/24974/1 "2022-08-29T09:38:57Z")

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Hello,

My question pertains to the conversion of a model back to a segmentation.

Currently i want to overlay 2 CT scans to calculate the dice score between 2 femoral segmentations (preoperative and postoperative).  
These CT’s are not in the same orientation and do not overlap.

I first segment both, convert them to a model and use SlicerIGT’s model registration to overlap these models. Then convert them back to a segmentation node and us slicerRT segment comparison to compute the dice score and hausdorff distances.

If i return both models back to a segmentation node, will there be a loss in quality or will the original segmentation stay intact?

Any suggestion to my way of approaching this would also be quite welcome.

Thank you in advance.

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [August 29, 2022, 5:55pm UTC](https://discourse.slicer.org/t/question-regarding-converting-a-model-back-to-a-segmentation-node/24974/2 "2022-08-29T17:55:51Z")

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You wouldn’t need to convert the models back to segmentations. You can just apply the transform to the segmentations and calculate your metrics in binary labelmap space.

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**Author:** ![jegberink](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jegberink/32/16031_2.png) [@jegberink](https://discourse.slicer.org/u/jegberink)\
**Post date:** [August 29, 2022, 6:52pm UTC](https://discourse.slicer.org/t/question-regarding-converting-a-model-back-to-a-segmentation-node/24974/3 "2022-08-29T18:52:46Z")

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Truly overcomplicated it. Thank you, such a simple solution.