The MRI is there to let your doctor know how your desease is progressing and how your MS medication is working. I would speak with them about your worries and thoughts about continued MRIs.

The bottom line is it's about knowledge.
Gives your neuro knowledge about any progression or not and something to talk about during an appointment.
Gives med providers statistical data on how well particular meds are doing.
Gives YOU knowledge about your own health position, the question there is do you want to know or prefer to bury your head in the sand ?
It's a question only you can answer.

Understandable ,the real question is to ask them if there is actually any value in doing it, you will know if you are better or worse than last time, will it effect treatment or is this just to satisfy there curiosity rather than help you?

That would mean another injection-bad rolly veins for that. Also, anxiety is not the problem. Bad veins for injecting contrast dye, and difficulty getting on gurney and and length of time for MRI .