Hi, daysma. I'm going to correct some of your language here, not to be a smarty pants, but because it's important to know the lingo if you're going to be doing any research on this and it will give you a better understanding.
An MRI shows lesions,not "flares" (also known as exacerbations). However, if you are i
n a flare and have an MRI with contrast, it is very possible that they will "light up". What the lit lesions represent is disease
activity. You can also have lesions light up without feeling that you are in a flare physically.
I'm not sure what you mean by shading, but by what you wrote your MRI showed 3 years ago, why do you say that it was normal?
As others have inferred, you can have MS and have normal MRIs. Disease activity is what causes lesions so that comes before the scarring -- and it can sometimes take a very, very long time for lesions to show up.