MR neurography scan
 

I just ran across this and thought I'd share it. As someone extremely allergic to Iodine so cannot have any tests with "contrast" this sounds great now to see if it is available from a different company that might be a tad bit closer to me.

This is an MRI that shows the nerves so it can be seen if they are damaged or compressed or whatever is causing the problem with them

http://www.neurography.com/