Dear SlicerSALT team,
Currently using SPHARM-PDM analysis, I wonder what interpretation could be given when there are surface differences between two groups but no volume differences (assessed with 2 different methods). It seems quite difficult to use the term “atrophy”… Moreover, the displacements are generally both inward and outward. What is the current physiopathological interpretation of this?
Best regards,
Quentin
Displacement differences locally can be due to local atrophy or growth, even if there is no global volume difference as small local size/volume differences may not rise to significant global size/volume differences.
Alternatively, there may be growth in one section and atrophy in another, thus you have local size differences that even out for a global analysis
Finally, you can also a local surface deformation differences without local volumetric differences, that usually then indicates that the surrounding of the structure is changing (e.g. a larger neighboring structure)
The visualizations of shape differences should provide insight to which situation you have, though we are aware that we need better & more intuitive visualizations