One other benefit to getting the MRI is that you are getting no radiation like you would in a CT. Even many doctors do not know that when they order a CT study for you, you are getting betwseeen 300 and 500 times the radiation of a normal chest x--ray. It's all accumulative in your lifetime and when I go for my annual head and neck exam, I opt for the MRI with injected contrast for this reason. The CT is still safe when you balance out the catching of a cancer early (at a curable stage) or tthe amount of rads that you are building up that they themselve could cause cancer later in your life. After all later in your life is an academic term if you died from a cancer they didn't catch early enough because you opted out of getting the right kind of scans for what the doc is looking for. But as you get further and further out from your original diagnosis and have more and more tests, it's something to think about.