We’ve been told over and over about the importance of early detection when it comes to health. The thinking goes that the sooner in its development a health problem is identified, the better the chance is of treating it and eliminating it. With that commonly-held belief, diagnostic screenings are well-accepted and have gradually become more numerous.

Among the more popular (at least among the general public, if not among physicians) recent forms of screening is the full-body MRI, which, as the name suggests, scans your whole body in search of any abnormalities.

That’s a good thing, right?

Well, maybe not.

While it may be appropriate for certain individuals in specific circumstances, there’s a few problems with doing full body scans on everybody.

First of all, any form of diagnostic imaging has the potential for what doctors call “incidental findings.” These are things that may technically be abnormal, but are not really clinically significant. For example, while targeted MRI of a specific area such as the lumbar spine may be very useful in diagnosing and forming treatment plans for someone with severe low back pain, studies have found that over half of the asymptomatic population has some significant abnormalities on lumbar MRI scans. It’s also quite common for someone who does have symptoms to have some abnormal MRI findings that most likely do not have anything to do with their symptoms.

When you expand the MRI scan to include the entire body, the potential for incidental findings is pretty high. Basically, if you look hard enough, you’ll probably find something wrong. Any diagnostic test is a “snapshot in time.” The body is continually healing and adapting its responses and something that’s abnormal today may fix itself in a few days, weeks, or months. If there’s signs and symptoms that indicate a more serious problem, more specific tests are generally more useful than the “shotgun” approach of a full-body MRI.

On the other side of the coin, the more complex and inclusive the imaging, there’s also an increased chance that something significant can be missed by the radiologist reading the scan. Looking for something that would explain a particular set of symptoms in a particular area (as is the case with most diagnostic imaging) is a lot easier than looking for anything abnormal anywhere. When I was in chiropractic school, our radiologists were always on us to collimate our X-rays as tightly as possible (limit the area of the image to only what was of interest) to reduce the extraneous area they would have to look at – the less they had to look at, the less work it was to read the X-rays, and the less likely they’d miss something.

Having a scan where something is missed can give a patient a false sense of security and may lead to them ignoring symptoms and thereby delaying appropriate evaluation and treatment.

This brings me back to early detection. While it can certainly be a good thing, there’s a potential for detection of health issues to actually be too early. Some conditions are very slow to develop and are not likely to cause significant harm before the patient dies of some other unrelated cause. Too early detection wouldn’t be so much of a problem if not for the anxiety that knowing something is abnormal that results - and the temptation of doctors and patients to treat something that doesn’t really need to be treated.

All treatments come with some risks - some more than others. Incidental findings and too-early detection can lead to risky treatment (in which the cure is potentially far worse than the disease). Even when the treatment does not cause physical harm, it very often does not provide any health benefit either, yet still incurs financial expense unnecessarily.

Because of these factors, the American College of Radiologists recommends against full-body MRI scans for most patients and this is a position I agree with. There are a few instances in which a full-body scan might be clinically justifiable, but if there’s no clear reason to have such a test, I recommend avoiding it.

Until next time…

George F. Best, D.C.