I am not sure if dealing with solidify modifier is safe procedure. I tried a lot, every time something was wrong. I mean complex geometries of lumen with irregular narrowing from thrombus or atherosclerosis. Every time I lost the ideal lumen of the vessel. Some solution to it, is shrink-wrap modifier, but to be honest it has big limitation like you mention before. I don't think that it would handle with dissections either.
So for that moment, I think we don't have perfect solution to mirror the ideal anatomy of vessel lumen. We can be close, but not accurate.
Maybe Dr. Mike has different opinion?
The second aspect is segmentation. What program you recommend ? Osiris or slicer?
I think that when we use the threshold for Hounsfield units for contrast medium , we also segment part of calcium atherosclerosis which has very big Hounsfield value. Around plaque segmentation see a transition zone which corresponds the value of Hounsfield for contrast medium which we see as very irregular surface. Of course we do smoothing as post processing in blender, however its not dealing perfectly with it. Even if it does, we lose ideal shape of lumen.
So same again, we are close but not accurate.
If anybody knows how to deal with these problem, please share with me.