I had an MR Enterography this past August when I was being diagnosed. Honestly, it's no big deal, if anything it's kind of boring. Basically, I had to get there about an hour before I was scheduled to go in and drink a bunch of contrast, which was probably the worst part about the whole thing. The stuff doesn't taste horrible, but it isn't fun to drink. I was then instructed to lay down on the machine bed while the technician hooked up an IV. You then enter a small tube like machine, your head will be sticking out from one end and your feet will be sticking out of the other. Then I basically spent the next hour laying there while being instructed by the machine to breathe in, hold your breath, release. After that, I was done and sent home. I personally thought it was cake.