Thank you, these are very nice renderings.
Did you use OptiX renderer in Paraview? Can you share the ParaView state file?
What was the rendering time in Paraview and Blender?
The Siemens example may use slightly higher resolution image, but probably the main difference is due to that Siemens uses some automatic segmentation to distinguish bone, vasculature, tools, etc. and render them with different material properties.
Maybe a more interesting scenario for using VtkNodes is for people developing custom application requiring surface editing tools ( e.g. dental implant, ad-hoc prosthesis planning …) those tools are missing in Vtk by design, while there are a plenty of them in Blender
Implant planning is more similar to CAD design and mostly done using parametric modeling, which Blender is probably not the best tool for. Also, implant planning does not require fancy rendering, but mostly relies on measurements on slice and projection views and simple 3D rendering.
But photorealistic rendering of a few nice images of the final plan could be useful for for communication with patients, training materials, and presentations.