From what I have ever seen, personally, on-line about brain tumors. They will be either little round ball shapes or will show up more gray and, how to describe, darker in color. There are photos out there, that you can seek out yourself.

For what it's worth, my neurologist, told me, I have too many to count.

If your doctor was just speaking out loud to himself, that seems like poor 'bedside' manners to me.

In the beginning, it doesn't sound abnormal to me, to have an MRI within three months of dx, then to space out to six months, then yearly. He may be seeing any difference, from the time you began Rebif? Not sure, that's mere speculation, on my part. Did you ask him, specifically why he's having them so close together?

Usually is a good idea to jot down questions, in a notebook, specifically for your illness, then write down the answers as you get them. I'd imagine he wouldn't mind waiting for you to jot down notes, as you ask him questions. And if he cannot do that for you, then perhaps, a new neurologist would be in order?