I recently had the privilege of meeting one of the engineers on the Watson project. From what he has shared, I believe that it will be challenging to replace radiologists with this technology. Sure, Watson can be trained to identify medical imagery, but that would be the only thing its training model would be capable of. I believe human radiologists will still be superior.
Huh. I don't have a source handy, but I recall hearing about field trials that showed Watson used as a diagnostic assistant was able to identify some hard to identify medical problems, where Watson's human counterparts were unable.