MRI’s certainly are claustrophobic. I had to take sedatives before my first MRI, but after that I’ve been fine (lost count long ago).
The secret is to close your eyes before going in and keep them closed until you come out. And make darned sure the fan is running cool air through the machine. The first time DH had an MRI they hadn’t turned on the fan and he kinda freaked. Second time fan on and no problems.
I used to recite poetry in my head to distract myself. But now I rather like all the noises the machine makes. It’s like being at a one person Rave. 🙂