I'm afraid I'll be claustrophobic plus what if I don't like what they find? Ack. I figure if I have a diagnosis, it's downhill from there!
@Jemima has suggested reinterpreting the closed MRI has something comforting, comfortable - praps similar to weighted blankets.
Other things would be making mental images like in a dentist's chair, only you can always press the button, which you can't at the dentist's ;-)
Relaxation, autogenic training, peaceful calm, ocean waves... or if the sounds get in the way try to get yourself 'hypnotized' by them.
Or I don't know if your imagination can manage: imagine phoning your friend...? What might you tell her - something about the situation you're in or better something completely different?
Myself I am actually a bit claustrophobic too, but I only open my eyes for a second and blend what I see away. I actually love MRIs tho, because I reinterpret the sounds as electronic music - a big dancefloor. A friend and my wife do that too, altho they don't love electronic music as much as I do. I'm always surprised how quickly I'm thru (I need to check a spinal tumour once a year.)
Downhill? Echoing
@Jemima: Depends how you use it, I'd suggest. If you think it'll go downhill, then it's unlikely you'll go uphill. ;-)
Normally a diagnosis does help see a direction for improving our condition whilst before we hang around aimless- and cluelessly...
A diagnosis can become a good information/tool. Not the best choice, but better than downhill is to make ourselves independent of it.
I "carry" the tumour like a duelling scar, or rather I ignore it pretty completely, altho many think I shd be peeing my pants, altho it's prolly harmless...