Yeah, I wasn't trying to be disagreeable, just pointing out that this is a very active area of research still, and there is always room for improvement. I work mostly with segmentation and shape analysis instead of registration, but I am involved with a project on multi-modal image fusion, which is even harder (and more interesting).
I've done a lot of work on multi-modal registration and would be interested in talking to you about this. It's an amazingly hard problem and I see a lot of wheels being reinvented whenever I look at what other people are doing.
My own work has been mostly commercial and so under NDA or otherwise unpublishable, but is primarily based on applications of the pseudo-correlation algorithm (Radcliffe, Rajapakshe, Shalev, Medical Physics, vol. 21, No. 6, pp. 761 769, June 1994.) I can be reached at tradcliffe at predictivepatterns.com if you're interested.
Awesome, we use a lot of PET/CT/MRI fusion imaging for computer assisted surgery and have an EOS scanner (statistical shape modeling). Just really awesome tech. Good ultrasound -> CT fusion would, I think, be indeed be a major breakthrough, allowing easy matching / guided procedures everywhere in the body but also for us as a secondary check on CAS / robotic accuracy.
