The stimulator electrodes that were implanted.
I lifted this whole smear from another website. It also has information on what the FDA warning was on implants and how Nelson misstates what they said. The whole thing is worth the read, but the pertinent part I am referring to is toward the bottom.
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"Finally, I don’t understand Dr. Nelson’s defense of the decision not to do an MRI. It adds nothing to the findings, is hardly objective and seems to serve only as CYA foliage.
He bases it on potential harm that could have happened to Terri because of the implanted stimulators—but says nothing about whether those stimulators couldn’t have been safely removed. Further, he has a little problem with how he argues that part of his report, calling his objectivity in to question."
"Dr. Boyle of Code Blue Blog disagreed with that assessment and he is a radiologist—the kind of dotor who would actually administer the MRI. He says in the post linked below (again in comments):"
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"In addition, it is hard to believe that anyone inserted electrodes, in 1992, that had paramagnetic properties that would preclude an MRI of the brain currently. I doubt that. Most of those devices are titanium or stainless steel, which are unaffected by MRI. Besides, with MRI, in that type of situation, the only reason not to do an MRI is because you are looking for information in the region of the artifact, where there would be distortion of the image.
If the items are not paramagnetic (like iron), there would be no danger and no contraindication to an MRI. Sounds bogus to me."
It's that white thing in the middle, I believe:
Dr. Boyle's point is interesting. I remember the excuse they used for not doing one, namely, that an MRI would fry the brain area around the implant. It was my understanding that a functional MRI (fMRI) could be done safely, but never was. However, I'm not a medic so would be glad to get professional advice on such questions.