A 5 foot, 275 pound woman who had a tumor on her spine was told to go to a zoo to have an MRI. This is because a hospital told her that she could not use a regular MRI machine because she was too heavy, and too wide, and wouldn't fit into the opening.
Medical Imaging in Kansas City can typically hold up to 440 pounds, but a person who weighs less than that could still be out of luck. All of this depends on how MRI machines are made and the part of the body which needs to be scanned.
The woman, Carolyn Ragan, ended up having two surgeries and some paralysis. She finally found an open MRI machine that held her weight, but she said it was embarrassing and frustrating. She also said that they should make MRI machines that fit everyone.