I'm so sorry to hear this. Just be polite but be very vocal to make sure they take care of you right. Let them know right away you need the hook up on the warm blankets. Every MRI I have gotten done in a hospital has been very close to the ER, and the ER always seems to be on point with warm blankets. If they are sending you to an imaging center it's hit or miss. Imaging centers seem to suck. I doubt they will keep the PCA. Even when it's not running the MRI really pulls at metal.
Good luck with everything. You've been through quite the shit storm but you've been weathering it very well. I think I would have lost my mind.

