hello, lets think in this fashion, MRI
is mostly considered having issues with the PACEMAKER, now new studies says the can do it in the old PACEMAKER, but do you think the new study was better then previous ones ? Then the argument is that same was the case then they said in the past that PACEMAKER may have issues with MRI, and They were sure of their studies, but the new studies are done to prove he previous studies wrong. So next step in a logical argument is how trustworthy the new studies as we know MAN MAKES MISTAKES. so its better to go with the old notion.
My point of View is
Well even if they say 99% is safe to do MRI on old pace maker , but what if you fall in the remaining 1% case , you being only one for you (only one of yourself exist) makes a 100% failure for you !! right?.
So I will Suggest to go for Cat- scan rather then to risk new problems with doing MRI.