From the New York Times…

But in many cases it is just not known whether what is seen on a scan is the cause of the pain. The problem is that all too often, no one knows what is normal.

“A patient comes in because he’s in pain,” said Dr. Nelda Wray, a senior research scientist at the Methodist Institute for Technology in Houston. “We see something in a scan, and we assume causation. But we have no idea of the prevalence of the abnormality in routine populations.”

Now, as more and more people have scans for everything from headaches to foot aches, more are left in a medical lurch, or with unnecessary or sometimes even harmful treatments, including surgery.

“Every time we get a new technology that provides insights into structures we didn’t encounter before, we end up saying, ‘Oh, my God, look at all those abnormalities.’ They might be dangerous,” said Dr. David Felson, a professor of medicine and epidemiology at Boston University Medical School. “Some are, some aren’t, but it ends up leading to a lot of care that’s unnecessary.”