Define what you mean by 'low cost'.
Not really my field but I'm guessing the need for the high power magnetic fields of a conventional MRI is because they are needed to align the H2O hydrogen protons in the first place before the proton spins are altered by the RF field.
If there are technological advances which allow you to create the magnetic fields using lower power electromagnets, or you have some other way to use the laws of physics to align the protons then you may succeed.
The image processing is another story.
Susan