There are a LOT of people here who are in limbo because they don't show any lesions on their MRI. There are folks who have white matter damage showing when they have a high Tesla MRI, but none when a lower T MRI is used.

MS attacks the gray matter in the brain too. The current theory is that it may be doing silent damage to the gray matter before any white matter damage shows.

The criteria for diagnosis (McDonald) calls for MRI lesions to be present.
The older criteria for diagnosis (Poser) also places a high priority on MRI findings
An even older criteria (Schumacher) did NOT call for MRI lesions, but that is because they didn't have MRI back then.

IMHO-There are a LOT of old neuros out there who do not keep up on clinical advances in diagnostic criteria because the way they have been trained has always worked for them OR they are not seeing people with MS, and when they suspect MS they send the person to a specialist. Some feel that the diagnosis will adversely affect the quality of life of the person and don't label it as MS, but just treat the symptoms.
My aunt has one of those neuros and I am shoving her kicking and screaming to a better doc so she can get a diagnosis for what ails her rather than just "treat the symptoms" treatment.