"MRI" covers a very wide variety of imaging and analysis techniques under the general category NMR (Nuclear Magnetic Resonance). Some forms of NMR analysis actually use the Earth's magnetic field (https://en.wikipedia.org/wiki/Earth%27s_field_NMR).
Basically, the stronger the fixed magnetic field, the more you can see and do.
Exactly. Super conductors are the ones I use and high temperature superconduction will likely make maintaining a super conductor much cheaper (after you spent lots on a whole new system).
