Volume size - labelmap vs closed surface

Hi, I’m using Slicer for research in which I segment and determine volume of a bone defect from a CT image, for the purpose of determining how much graft material is needed. What is the difference between labelmap vs closed surface volume, and which one is best suited for my needs?

The difference is not big, less than 2% but this being a research obviously I want to be as accurate as possible, and also I want to be able to explain why I’m choosing one over the other. I’m new to Slicer and 3D stuff, and am a clinician by trade so all of this is new to me.

Thank you !

They use slightly different approaches. Labelmap volume just counts the number of ‘on’ voxels and multiplies by the voxel size. Closed surface volume uses the smoothed surface model and an integration of the volume based on the triangulated surface. Typically the closed surface more closely matches the real contours of the anatomy.

https://slicer.readthedocs.io/en/latest/user_guide/modules/segmentstatistics.html

Thank you! I wasn’t sure what labelmap means, that’s helpful.