Maria, I don't know about MRI but I was supposed to have a CAT scan today (didn't happen because I had too much of the wrong barium in me) and I could also wear my own clothes as long as it had no metal. So I wore my undies (obviously ), socks, a sports bra that has no metal, sweatpants with a drawstring, long-sleeve tee, and a sweatshirt. All these were fine and I didn't have to wear the stupid gown.