For most healthy people, full-body MRIs aren’t necessary. It’s much more important to work with your provider and discuss your own risks and health goals.
Wellness influencers and celebrities have been really into getting full-body magnetic resonance images, or MRIs, just to check to see if they might have cancer or other conditions. So should we all be getting MRIs to screen for early cancer? Could it help us live longer? Possibly. But for the “average risk” person, there is a chance that the MRI will find insignificant results that can lead to expensive and unnecessary procedures.
“Average risk” for a particular disease means that your level of risk is approximately as high as the risk in the general population. For example, let’s say 10% of people get a particular cancer by the age of 80, that’s the average risk. But if you have a family history of that cancer, then you might be at an above-average risk. Lifestyle factors, like smoking, can also increase risk for certain cancers. Your healthcare provider can give you guidance for screenings based on your risk factors and family history.
MRI safety
Overall, MRIs are very safe! Unlike X-rays, which expose you to a small amount of radiation (which is also safe when used appropriately), MRI machines use a large magnet and the magic of physics to create an image of your insides. However, depending on what part of your body is being screened, you may need to be given oral or intravenous “dye” called contrast. Contrast allows different tissues, organs, and/or blood vessels to be seen more clearly in order to better assess for tumors or sites of inflammation/infection. The most common MRI contrast is a compound called gadolinium and while it’s usually safe, there can be some side effects. Contrast can cause an allergic reaction, and it can also potentially stay in your body for months or even years. This hasn’t been linked to any adverse effects in people with normal kidney function. Overall, the benefits of necessary MRIs with contrast outweigh any harms, but it’s something to think about if you’re deciding to get an MRI that your healthcare provider hasn’t recommended. In patients with kidney disease, contrast can cause some kidney problems, so talking to your healthcare clinician is really important. Some newer contrast agents might be safer for those with kidney disease which is why checking in with a clinician is so necessary. As a rule of thumb, it’s a good idea to drink lots of water if you have to get an MRI with contrast.
Though these side effects are pretty rare, making the decision to get an MRI with contrast should be done with a healthcare provider for a specific reason, rather than for just a general screening.
Also, to get an MRI, your whole body goes inside a pretty small tube, and for people who are claustrophobic, it’s usually not a pleasant experience. Sometimes, open-air MRIs are available but if not, your healthcare provider can prescribe medication to help you feel a little calmer if you need to get an MRI.
So if MRIs are safe, why not get them frequently?
MRIs can reveal important and serious findings, such as cancer. But sometimes scans can show things that your healthcare provider wasn’t necessarily looking for. This is what healthcare clinicians call “incidental findings.” Incidental findings can be something serious or they can be variations of “normal” that usually won’t impact your health in any real way. There are incidental findings in 15-30% of scans! For example, a friend had to get a brain MRI because of her constant headaches. She found out that she has something called “low-sitting brain”, but after a panicky call to her neurologist, she discovered that it was a normal “abnormal” brain MRI finding! She eventually found out what was going on with her headaches, and it wasn’t at all related to her brain.
Ultimately, incidental findings can lead to over-treatment, which can harm you in the long run. In many circumstances, extra surgeries and biopsies for incidental findings can cause more harm than good. For example, one study found that getting an abdominal CT scan increased the risk of finding an incidental kidney mass which then increased the risk of kidney removal surgery. You can’t tell from a scan if a mass is cancerous or not and removing a healthy kidney has risks, too. Though surgery is safe overall, all procedures can have complications, including surgical site infections and only having one kidney means the other kidney has to work a lot harder to filter your blood. This is why it’s important to weigh risks and benefits of getting a full-body MRI with a healthcare clinician.
It’s also important to remember that an MRI is just giving you a snapshot of a moment in time. Just because there is nothing found at one point, doesn’t mean that cancer will never develop. That’s why it’s important to continue following up with a healthcare provider over time and monitor any new changes in your body or symptoms like night sweats or weight loss.
Cost
Getting an MRI if your healthcare provider doesn’t specifically recommend one might not be covered by insurance. Different companies charge different prices for full-body MRIs, but it can cost thousands of dollars. Further procedures for incidental findings can also be expensive.
⚖️ Health Equity Alert
There are a lot of health equity concerns when it comes to full-body MRIs. Many of the celebrities who are advertising full-body MRIs are likely getting discounted scans in return for publicity, whereas the average person would have to pay out of pocket. That means that there is a larger cost burden for those with lower incomes. Many people without insurance or who are underinsured might not have access to MRIs even if they are necessary and warranted.
Normal screening tests
When healthcare providers think about what screening tests a patient needs, they consider a lot of factors, such as your personal medical and family medical history.
There are specific screening measures for a lot of different diseases. These guidelines have been put together by scientists and doctors based on lots of research to ensure proper care. Screening guidelines change all the time based on new data. For example, the screening age for colonoscopies is now younger than it was before because people have started getting diagnosed with colon cancer at younger ages (see further reading for extra info on screening tests!).
Screening guidelines also change based on your personal and family history, so it’s important to talk to a healthcare provider to learn what you should focus on. For example, if breast cancer runs in your family, your provider might recommend getting mammograms starting at an earlier age. There are some familial cancer syndromes where frequent, full-body MRI might be necessary, but these are pretty rare.
So, for most healthy people, no, full-body MRIs aren’t necessary. It’s much more important to work with your provider and discuss your own risks and health goals.
Further reading:
American Journal of Roentgenology – Incidental findings
Dana-Farber Cancer Institute – Full-body MRIs: What you need to know
Those Nerdy Girls – Over-diagnosis and Screening tests
A Selection of TNG posts on Colon cancer screening
Podcast – Dr. Mike Podcast about full-body MRIs
