After reading this thread, I am seriously reconsidering asking a doc to order an MRI for my ankle, or for the rest of me for that matter....a friend had suggested it, as I have a sprain that is actually a re-sprain that is slow to heal. I have yet to see an orthopoedic surgeon for it, but plan on it soon.
I gotta get on some BF & C before I consider any of these, I am sure;)