X-rays and magnetic resonance imaging (MRI) are common tests for first-time episodes of low back pain (LBP). It’s easy to think that changes seen are the cause of new symptoms. Doctors know this isn’t always true because many people with even worse-looking imaging studies can have no symptoms at all.
Some doctors prefer to treat the problem symptomatically. Then if the pain doesn’t go away, further testing can be done. It’s possible that early stages of inflammation won’t show up on the MRI anyway so waiting six weeks or more may actually show a more accurate picture.
A recent study from the University of Hawaii took baseline X-rays and MRIs of 200 subjects without back pain. Anyone who developed first-time back pain was then re-tested. The idea was to see if changes associated with the trauma would be apparent on the new MRIs.
Less than five per cent of the follow-up MR scans showed relevant new findings. Even with an episode of trauma, changes on MRIs were few and far between. Given the high cost of MRIs, they are not advised for routine exam of LBP. MRIs may be advised for patients who have been treated conservatively without improvement.