Comparison of CBCT images with regard to preoperative and postoperative position and relation

Dear colleagues,

I work as a facial surgeon at a German university hospital and we would very much like to compare the position of a mandible using CBCT images. This is to compare tumour patients and orthopaedic dysgnathia patients to ensure the best possible outcome.

We have already tried different things but always without satisfactory results.

  1. is there a possibility to overlay the two CBCT images directly, automated and standardised?
  2. is there a possibility to determine the degree of agreement on the basis of numerical values (e.g. percentage or other numerical scales)?
  3. is it possible to display the degree of superimposition using a colour scheme?

Thank you for your support

Kind regards

A. Vollmer

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Dear Andreas,

Regarding question 1) :
a) To overlay, you need to select your CBCT volumes as background AND background volumes (see here how to do so User Interface — 3D Slicer documentation). You can then change foreground opacity to see the underlying background volume.
b) For manually aligning volumes, you need to play with the “transform” module: Transforms — 3D Slicer documentation
c) For automatic alignment, you need to “register” the volumes: Documentation/Nightly/Training - Slicer Wiki

For you other questions, it is doable, but my understanding is that requires a bit of Python coding.

Regards, Julien.

You can get numerical (maximum distance) and visual comparison (with coloring) without Python scripting if you can segment the same anatomical structure in both images. You can get distance between segments using Segment Comparison module (in SlicerRT extension) and coloring based on distance using Model To Model Distance module (in ModelToModelDistance extension).