MRI was not possible in Terri's case because of an impant to the brain that was designed to stimulate it years ago. It was a failed treatment so MRIs were no longer possible.
That implant could have been removed. The doctor told Michael to have it removed. He didn't. I don't wish to speculate as to why.
Terri was judged to be in this "permanent" state based on 45 minutes of observation by a strongly pro-euthanasia doctor.
I see you don't know what you're talking about regarding an MRI also. Wow, you really do enjoy those nasty feet of yours in your mouth.