For most people without symptoms, risk factors or a relevant family history, a full-body MRI is not worth doing as a screening test. The American College of Radiology has said there is not enough evidence to recommend it, and no major U.S. guideline includes it. [1] MRI itself is an excellent test. The question is whether scanning the whole body of a healthy person, without a specific question, does more good than harm.
What a full-body MRI does
MRI uses a strong magnetic field and radio waves rather than ionizing radiation, which is one reason whole-body scans are marketed as safe. A typical scan images the brain, neck, chest, abdomen and pelvis in one session. It is usually self-paid, and prices vary widely.
Protocols also differ between providers: some use contrast, some include the heart or spine, and image quality depends on the scanner and the time spent. Two products both called a full-body MRI may not be comparable.
It is not equally good at everything. It does not replace the screening tests that have evidence behind them, such as mammography, colorectal cancer screening, cervical screening or, for eligible people, low-dose CT for lung cancer. [3]
What the evidence shows
No proven benefit for healthy people. In its 2023 statement, the American College of Radiology said there is no documented evidence that total body screening is cost-efficient or effective in prolonging life. [1] There are no randomized trials showing that whole-body MRI screening reduces deaths in the general population.
Frequent incidental findings. Scans of healthy people often find something: a cyst, a nodule, a small spot of uncertain meaning. A 2018 review in the BMJ of 32 studies, covering more than 27,000 apparently healthy adults, estimated that about 4 percent of combined brain and body scans showed a potentially serious incidental finding, with wide variation between studies. [2] Many findings turn out to be harmless, but each one can lead to more scans, biopsies, cost and worry.
Reassurance is not the same as protection. A normal scan is a snapshot. It does not rule out conditions MRI detects poorly, and it does not change the value of blood pressure, cholesterol and other proven checks.
When MRI clearly helps
MRI is valuable when it is aimed at a specific question or a specific level of risk.
- Investigating symptoms or an abnormal result, where the choice of MRI and the body area is guided by the problem.
- Breast MRI for women at high risk, for example because of an inherited gene change, as a supplement to mammography. [4]
- Inherited cancer syndromes. For people with certain rare conditions, such as Li-Fraumeni syndrome, expert groups recommend regular whole-body MRI as part of a surveillance program. [5]
- Heart and blood vessel questions, where cardiac MRI can assess heart muscle and function when there is a clinical reason.
If you are considering a full-body scan anyway
- Who reads the images, and are they board-certified radiologists?
- How are incidental findings reported, and who arranges and explains the follow-up?
- What will follow-up cost, and is it covered?
- Will contrast be used, and are there implants or devices that make MRI unsafe for you?
A physician who knows your history can help you decide whether imaging is likely to answer a real question, and which test fits. If you decide to go ahead, ask for the full report and the images, and share them with your own physician so any finding can be followed up in context.
Read more about MRI and DEXA at RGH and a more useful conversation about preventive care.
General information only; not medical advice. In an emergency, call 911.
About the author. Dr. Irfan Siddiqui provides concierge care through Regenerative Health & Wellness. More about Dr. Siddiqui · Explore membership.