MRIs are total shitlords. The normal sized one is pretty cozy you might say. where a normal person (I am 5'10") can lift your hand wrist touching your leg and touch the top of the tube. So you have like 4-6 inches clearance if that. It's pretty claustrophobic. Around 22-23 inch closed tube. The large one is 30 inches much more spacious and not so scary. The one they use for fats is an open bore so it's not even a tube it's like a round bed that has a lift.