The location would be somewhat atypical for a primary demyelinating process, such as MS, but this is difficult to completely exclude. No focal parenchymal masses are identified. There is a slight rotation of C2 relative to C1 with that vertebra angles slightly to the right. Significance of this is not clear. The CT number consider fatty tissue.
Distal segment is normal size, diseased.
Thanks for your question. You have presented a rather complex set of symptoms which received an impressive neurological and medical evaluation. I will attempt to address the first set of symptoms, namely the visual ones triggered by extreme neck movements. As you have already pointed out during your message none of the exams attempted to dynamically assess possible changes in blood flow to brain when the neck movements were executed. A significant portion of the described visual symptoms could result from a transient decrease in blood flow to the visual cortex, which is located in the posterior region of the brain.