I had to have an arthrogram in my right knee shortly after the 2nd injury to it at work( RSD present in right knee but ignored).

First, an MRI taken before dye injected.
(This showed that my initial injury was messed up and the new injury tearing into old injury,also..should have been enough proof)

Next, dye injected.( Doc had to inject me twice;injected into the fat pad of my knee..OMG!)

Last, another MRI taken.( in pain from the injection..hard to hold still for that MRI)

There was no numbing done..the knee was inflamed and it was a very painful experience. The injection doc and his asst., kept apologizing to me... I would not endure it again.

This was my experience..maybe your wife would have a better one. I sure hope so...