MRI alternatives

Dear Dr. Roach: A few years ago, my father had two spinal cord stimulators implanted in his back to help with his lower back pain. He recently had a stroke, and after a CAT scan, was scheduled for an MRI. The MRI was canceled as soon as the technician became aware of his implants. Are there any alternatives for patients with these implants who are in need of an MRI? — D.T.

Answer: An implantable spinal cord stimulator is a device used to send electrical impulses in order to reduce chronic pain, especially in people with unsuccessful back surgery, complex regional pain syndrome and a few other indications. They are used in people who have failed other approaches, and are moderately successful, with some people getting very good relief and others not having much benefit at all. Hence, a trial usually is done to see whether it will be effective in an individual before putting in a permanent device.

Some spinal cord stimulators are made out of metal that is compatible with MRI; however, if it is not, then performing an MRI is dangerous — movement of the unit under the powerful magnetic field is possible, as is a heating up of the metal parts of the unit. You should find the original informational materials your father should have received when he had the device implanted. If you are unable to locate these, the person who implanted it should have these records.

If you cannot prove that both of his stimulators are approved for MRI, then he is left with a CT scan, sometimes combined with a dye study, a myelogram. We used these a lot before MRI became available, though they don’t have the incredible resolution of a modern MRI machine.