I am using pyRadiomics to analyzed 3D segmentation of tumors.
I noticed the feature " Sphericity" and it is very useful for tumor analysis. Besides this feauture, I want to calculate the " Ellipsoidity" of a tumor.
When the tumor is in the shape of a very prolate or oblate ellipsoid, it would have a low sphericity but the ellipsoidity would be 1. So the featue “Ellipsoidity” could also be very useful.
Can I do this with pyRadiomics?
Thank you in advance.
I don’t know what pyradiomics can compute, but you can use Slicer’s segment statistics module to compute many shape metrics: roundness, flatness, elongation, principal moments, principal axis directions, oriented bounding box diameters, Feret diameter, etc. This allows rich shape characterization, including assessing “ellipsoidity”.
See some more information in this topic:
All shape features available in PyRadiomics can be found here. This also includes principal axes length, but no specific “ellipsoidity” formula. Do you have a equation to calculate this?
Sorry for the late reply, I just noticed it.
Thank you for the information. I’ll check 3D slicer.
I read papers that says it equals the ratio of one 3D object’s volume to the volume to the object’s fitting ellipsoid. And the fitting ellipsoid can be calculated this way:
Chaudhuri, B. B., & Samanta, G. P. (1991). Elliptic fit of objects in two and three dimensions by moment of inertia optimization. Pattern Recognition Letters , 12 (1), 1-7.