Informed Risk/Benefit Analysis. Real world example. A 3D chess game of expert knowledge.
I really liked the tv series The Queen's Gambit. The story of a young woman's incredible ability to play chess, and especially how they showed her visualizing the game in space.
Any real decision-making that involves multiple moving parts and a fair amount of uncertainty is much like a 3D chess match. Except in health care the game played is about your life. When I advise people on what to do, I tell them in terms, based on everything I know on the entirety of the picture that you describe, this is what I would do in your situation. Yes I am an expert on MRI and the use of GBCAs in MRI, so I do have that bias, but I also have thought deeply on the limitations and risks, so my position is a cautious but well informed analysis of risks with many years of experience with studying disease in a university setting, and have written numerous publications, which is a yardstick for thinking seriously about things. So I tell people what I would do, but that is not to say that I am 100% right, or that I can guarantee an outcome. I have learned over the years that essentially anything can happen in 1 in 1 million cases; even in the most skilled hands most predictable bad outcomes can happen in 1 in 100,000 cases; with the vagaries in life many nasty things can happen in 1 in 10,000 cases.
With that background, here is a current real world example of how I assess risk/benefit for a particular case, which also has wide applicability and that is why I am posting it as a blog.
Your question is: can your provide an informed analysis of risk/benefit for obtaining an MRI to look for Multiple Myeloma (or generalizing it to any malignant disease) where the suspicion is quite reasonable. Overall the risk is relatively low for developing GDD. White and female are baseline risks, but where the risks become more worrisome to develop GDD, is a history of extreme sensitivity to chemicals - multiple chemical sensitivity syndrome; and related: chronic Lyme disease, chronic severe mold allergy. Basically other forms of immunity mediated inflammatory diseases (IMID), many of which cause T cell dysregulation. MRI with Gd contrast is very good at seeing Multiple Myeloma (MM) lesions, . with essential use of a fat suppressed T1 sequence (such as fat suppressed T1 weighted spoiled gradient echo- my preferred sequence). GBCA-enhanced fat suppressed T1 weighted spoiled gradient echo- is effective at detecting multiple myeloma bone lesions, and additional findings outside of the skeleton, lymph nodes, liver lesions, etc. Diffusion Weighted Imaging (DWI) sequence does not require Gd, and can demonstrate but I am not sure it is sufficiently good to evaluate for subtle lesions of MM. It should also be performed on a relatively new (within 5 years old) MR machine.
So, no history of prior reactions to GBCA contrast, no history of the large family of IMID conditions, then the risks for GDD are < 1 in 10,000. Multiple myeloma is a serious and not rare malignant disease, and there are good clinical reasons to be concerned for it, so malignant disease, reasonable risk, a high category for obtaining maximal imaging evaluation. The additional wild card is the study has to be performed well and interpreted by experienced readers. For example I mentioned the crucial importance that the images be performed as T1 fat suppressed sequences, and I much prefer spoiled gradient echo, and on a relatively new system 1.5 or 3T, 3T somewhat better since thinner slices can be obtained. The study could be performed with DWI alone if there are significant risks for GDD (or great fear on the part of the patient). All the above being correct, if it was me I would definitely have a GBCA-enhanced MRI.
So risk/benefit is a very complex decision, and to be done well is like playing a 3D chess game. The physician has to weigh out all the possibilities, with the additional factor of also being aware of all the major likely adverse effects (eg: knowing GDD). There is the additional component (maybe making it a 4D chess game) that the study must be performed well and interpreted by skilled radiologists.
Richard Semelka, MD