Hi Legz,
I once asked my MS Specialist about that same question. He said my lesions did not enhance after an exacerbation. I said I just finished with steroids. Is that why?

I then asked him, do you think that because the steroids reduce inflammation, and inflammation is what enhances around the lesions (the fluid around the lesion is inflammation), that that is why the lesions look inactive and do not enhance?

He said yes, steroids do take away the fluid around the active lesions, just like it would do the same for fluid (inflammation and swelling) around an Arthritic knee.

He said that is how the steroids work, to help you when you have an exacerbation. They first remove the inflammation around the lesion and then help heal them.

So quoting him, I would say yes to your question. It makes since. No more inflammation or fluid around a lesion, so the contrast does not go into the fluid and enhance it.

That was quick though. Maybe you did not have much inflammation around the 2 new lesions. Or they were starting to heal on their own before the steroids were taken.

Or maybe the 2 new lesions were tiny before, did not show up last time, so not really new ones. They can get a bit bigger and finally show up, but not as enhancing ones in that case.

As for the progression (size of lesions?), maybe the MRI machine got better pictures of the brain/cervical this time. Did you change machines or places you went to? Or do you mean you are progression?

I hope I got this explained right, the way he said it to me. I think I confused myself in this post. I went to a BBQ today and I am tired. A little brain fog setting in.

These are just my thoughts, or what my Neuro said. You should ask your Neuro why? He must have some answers for you. He saw the MRI's and examined you prior to the steroids.