Safety of MRI tests and contrast agents

Are MRI tests safe?

The usual MRI contrast agent is Gadolinium-based, and is not radioactive. MRI machines themselves use magnetic fields and not radiation. Fortunately, it's not possible to have an “overexposure” of magnetism. CAT or PET scans are a much different story, though, since they do use radiation.

I’ve had a number of MRIs, and I consider them to be the safest of the available imaging technologies. If you are having symptoms that warrant the test, then in my opinion it would be foolish to deny the use of a contrast agent if the study was ordered using one. I’m not saying contrast is zero-risk, but the risk of misdiagnosis without contrast (when needed) seems to me to be much higher than the risk of the contrast itself being a problem. I asked a radiologist about the risks once, and he said that although they have everyone sign a liability waiver form due to the theoretical risk, that he personally had never seen anyone react adversely to the contrast agent, nor had any of his co-workers.

The issue is that without contrast, many physical structures and details simply aren’t visible. That also means that a more correct response to not seeing anything with a non-contrast test would be to order one with contrast, not to just say that you’re all done. And if they do see something without contrast, they would have generally seen more details and therefore know more about what’s happening if it had been done with contrast.

However, not all exams require contrast; it depends on which part of the body is being imaged.