I only saw the one picture, not all the images. Yes, you can do a PET with a stimulator. It looks like she has a shunt on the CT, but it's well documented that she also has a thalamic stimulator. She might have both. For what it's worth I would guess that she almost certainly would have had a MRI done in 1990 before the stimulator was placed.
I don't think fMRI was in business till the mid 90's Doc.