I don't agree with your neurologist about "to be diagnosed, lesions
have to appear over time and space." I have had PPMS for eighteen
years, my MRIs have never changed since the first MRI (each subsequent
MRI with and without gadolinium). I have never had an exacerbation
that is why my MS is classified as PPMS. I just saw my neurologist
last Thursday. (He's director of the Maxine Messinger MS Clinic in
Houston). I asked him again how he would classify my MS. And, once
more the diagnosis was PPMS.

I have certainly become more disabled over the years, but that has to
do with the nerve endings (axions) dying under the lesions.

MS certainly is incredibly frustrating even for the doctors.