[ChrisMarshallNY]

Also, they need to keep vats of liquid helium around.

Difficult stuff to store. I knew they needed cold gas, but liquid helium is crazy.

[jahnu]

There was some buzz years ago about using liquid nitrogen instead but I don’t know if it made it into widespread production

https://www.wired.com/story/mri-magnet-cooling/

[nullc]

Sounds like that's more about using a cryocooler to minimize the helium used-- but presumably that requires keeping the coils in a particularly hard vacuum to adequately insulate them.

There is some research towards operating at liquid hydrogen temperatures -- but hydrogen has its own logistical challenges.