When I was first dx with MS, I got one about every year and then after 3 years, I went about 10 years without one. It is not necessary unless you are changing medications or have a bad episode.

I think that they are costly waste of money unless the doctor doesn't know what to do. The co-pay before Medicare was over $1K, but now with Medicare it is a lot cheaper. I doo not want to get them that much. Boy they are LOUD.

I get MRIs every time I have a flair-up (or what my neuro thinks is a flair-up because I have no real idea). Out-patient clinic where I get them done know me by sight, now. We joke that I can stick to my fridge, at this point. X)

I have and two MRIs in my life. The first one was a botched up job and had to be redone. The second one led to my diagnosis of multiple sclerosis.

Being I am PPMS from the get go and nothing can be done for me, I've never had another one. That is about the only good thing I can say about having PPMS (Primary Progressive Multiple Sclerosis). :(

I no longer get MRI's
the way my neurologist explained it to me is this way.
You can have a lots of symptoms and very few lesions. Or you can have lots of lesions but very few symptoms.
The MRI'S will tell them if you have more lesions less lesions bigger or smaller lesions. But they do not treat the lesions they treat your symptoms.
Four years ago I was paralyzed from the chest down having difficulty breathing. They did an MRI a couple of months ago for another reason not to check the MS. But during the last four years the lesions in my brain have multiplied the lesions on my spinal cord have grown. But I can now move my legs and I can stand, I transfer in and out of my wheelchair.

So from that I can understand why your neurologist with focus on your symptoms.

Hope this helps