I've heard that it doesnt matter the size of the lesion, it's the location of the lesion.

I'm sure you can have a ginormous lesion somewhere, and not have any symptoms, but then you could also have a little one that doesnt show on the usual MRI scans, but can be giving you some really troubling symptoms.

You might have to look back several pages (or more) to find the thread, but there's a thread lurking around here somewhere where someone had posted an explanation on MRIs and how you can not be showing lesions, but just because they're not showing up doesnt mean that you dont have any lesions. It's just possible that the MRI might not be strong enough to be able to pick them up yet.