this is an MRI of a head.
did you have to wear anything particular?
take out earrings? no jewelry?
about how long does it take?
do you have to stay awake? do they talk to you while you're inside the machine?
I've had MRI's of my neck, shoulder, and lower back. All 3 were "open" MRI's. I just didn't wear any jewelry (besides my wedding band, and I locked that up in the changing room) - at the facility I went to, you were allowed to bring a guest with you into the room and I believe they had to remove their jewelry as well.
All of mine were pretty quick - no more than 30 minutes or so.
I was on valium for all three (I don't do closed in spaces very well), and probably could have fallen asleep, but it's pretty noisy. You aren't supposed to move, either. I never had anybody talk to me while I was in the machine (mine were all "open" MRI's, if that makes a difference). There was a recording that would tell me when they were going to start (at least I think there was - like I said, I was pretty out of it due to the valium).
They really weren't that bad at all.
Good luck!!
ETA: They provided scrubs for me to change in to, and I had to fill out the paperwork another poster referenced about surgical pins, screws, etc... They were very helpful, and I was able to call to ask them about their processes for the day, so that I was prepared (I really hate going into something not knowing what to expect).