OMG I've never heard of this. I've had a couple of MRI's with barium and never had an NG tube. I think if it was me, I would have to put up a HUGE fight before I let them do that, and they would need to give me some serious drugs first. That is one of the reasons I stay home when I get blockages. I am petrified of the NG tube. I will be hoping and praying that you don't have to have it done that way, it just sounds way too horrible.