As someone who knows more about words than superconductors, gentle correction in case it is an actual misunderstanding instead of misspeaking, but a correctly running MRI shouldn't ever CONSUME the liquid helium, it would recycle as much as possible.

But as a newly self-proclaimed expert on superconductors as well, yeah this would probably help MRIs. My understanding is that the reason for superconductors in MRIs is so that the wires doing the electricity stuff don't interfere with the small electrical responses from the tissue it's measuring. Without resistance, you don't get magnetic fields around the wires or something.

And potentially reduce the cost of fusion reactors by tens of percent.

Yes