Hi, Rachel and welcome.
FYI, there are other places MS lesions can be found besides the periventricular region although it is true that they tend to be deeper in the white matter. That said, since the time of my dx I've seen a few cases of "atypical" MS.
A few questions...
Is the neurologist you're seeing an MS specialist or a regular neurologist and have you had an MRI of just your c-spine or did they do the t-spine as well? Also, I assume they tested you for MS mimics like Lyme, B-12 deficiency, etc.?