3rd post down in my link, look at my MRI. White spots are lesions. Depending on series/filter used, they'll show up white or dark and usually smaller then mine. 20 is alot so start researching meds and looking into every blood test for lack of a vitamin.
Ask location that performed MRI for it on CD. Cost from free to $25, post them here.

http://neurotalk.psychcentral.com/thread177183.html