[bialpio]

My understanding is that both MRIs and ultrasounds do not introduce problems.

[ahtihn]

MRIs by themselves no, but depending on what you want to actually see you need to inject a contrast agent which is probably not something you want to do too frequently.

[bialpio]

Good point, I was not thinking about MRIs with contrast.

[Levitz]

Nobody is proposing this though