I just read the above posts and agree with the others about the Valium...you really need to let your doc aware of how you don't think the Valium works very well for you.
There are other kinds of medication that could be used.
I had an MRI on my brain and my sense of humor is like yours, I said something about , "so you didn't find anything, HUM"?
You'll do just fine in an open type MRI - I'm sure of it. Thanks for your service too.