When Should You Have an MRI for Your Back Pain?

At what point should your doctor take a look inside your back with a high-tech MRI or CT scan, or even an old-fashioned X-ray? In most cases, the answer is later rather than sooner.

The rap against MRIs as a diagnostic tool for low back pain is not that the scans usually reveal nothing, or even that they're expensive, it's that they often show a lot of abnormalities in the back that may have nothing to do with the source of your pain. With aging, the hard-working spine begins to show signs of wear and tear, such as degeneration of disks and arthritis in joints. But for a pain condition that in most cases resolves itself in less than two months without dramatic intervention, that kind of information isn't particularly helpful.

"If you take a hundred patients who are middle-aged who have no back problems, and you get an MRI of their back, a third of them are going to have abnormal MRIs," says Jeffrey Goldstein, MD, medical director of the Spine Service at the New York University Hospital for Joint Diseases.

For all of the potentially irrelevant information they reveal, MRIs do not expose your body to radiation. But CT scans and X-rays do, which make them especially risky for women with lower back pain who are in their childbearing years. Recent guidelines published in the Annals of Internal Medicine pointed out that the amount of radiation absorbed by the ovaries from a single X-ray of the lumbar spine (the five lower vertebrae) is equivalent to the amount they would absorb from a year's worth of