Ask about open MRI. The pictures they get from those are MUCH better than when they first came out.
If that's not an option:
1) Xanax or valium. So you can't drive yourself.
2) Use a sleep mask for your eyes.
3) Headphones (they usually have headphones that they'll play music for you--and they can talk to you and give you instructions.).
4) if they don't have headphones, bring your own, noise cancelling ones, or go for really good earplugs.
My last MRI, I FREAKED OUT! My hands started to fall asleep, and when that happened, I felt like I couldn't breathe, and then I felt like I was being buried alive.
So I had to hit the panic button and have them get me out of the tube.
I wasn't sedated for mine. Next time I go, I wlll be sedated.