Last Updated: 2003-06-03 16:42:17 -0400 (Reuters Health)

NEW YORK (Reuters Health) - An imaging technique known as rapid MRI may offer no benefit beyond conventional X-rays in diagnosing many cases of lower back pain, according to a report released Tuesday.

U.S. researchers found that one year after either test people who had rapid MRIs reported the same levels of pain and physical functioning as people who received X-rays to diagnose the cause of their low back pain.

And of the 380 study participants, 10 people who received rapid MRI also underwent back surgery, versus four of those who got X-rays. All the patients had a similar type of back pain when the study began.

Moreover, the cost associated with the rapid MRI technique -- such as the price of the technique, the prescriptions patients filled, and the number of doctor visits they scheduled after the screening -- was an average of $321 more per patient than the cost associated with X-rays.

And given the large number of people who suffer from low back pain, that difference in cost can quickly add up, study author Dr. Jeffrey G. Jarvik of the University of Washington in Seattle told Reuters Health.

"Any slight change you make in the diagnosis or treatment of low back pain results in a big impact on society," he said.

The findings appear in the June 4th issue of the Journal of the American Medical Association.

In an interview, Jarvik explained that MRIs capture images of the body that are much more detailed than those seen from X-rays. Rapid MRI is a modified form of standard MRI that produces images more quickly and with less expense.

Jarvik said doctors have both wondered whether MRIs might both help patients -- by picking up conditions missed by X-rays -- and harm them, by finding abnormalities that are not the cause of back pain, leading to further invasive tests or treatments, which may result in only hurting patients more.

The current study "means that one diagnostic test doesn't result in patients doing better than the other diagnostic test," Jarvik said.

The researcher noted that "it's somewhat reassuring that patients (who receive rapid MRI) didn't do worse."

"Of course," he added, "they didn't do better, either."

Interestingly, Jarvik and his colleagues discovered that patients, when reporting about their experience, appeared more satisfied with the rapid MRI technique. More MRI patients, for example, said they were "reassured" by the test results.

However, that reassurance comes with extra costs and no apparent physical benefit, Jarvik noted. "It just becomes a question of how much you're willing to pay for that reassurance," he said.

To compare X-rays to rapid MRIs, Jarvik and his colleagues randomly assigned 380 adult patients to undergo one of the procedures, and then interviewed them 12 months later. All had been referred by their primary care doctor for evaluation of their lower back complaints.

Jarvik noted that the findings may pertain only to people going to their primary care physicians for low back pain because many such patients are reporting the problem for the first time, and the majority of people with new back pain get better relatively soon.

In contrast, people who go to an orthopedic surgeon or another specialist as a result of back pain have likely had the problem for some time, and may have different outcomes with diagnostic tests, Jarvik said.

Dr. Nortin M. Hadler of the University of North Carolina at Chapel Hill, who wrote an accompanying editorial, said that it may be difficult for patients to understand that images of their spine cannot always pinpoint the cause of their low back pain -- or why some conditions found in those images are not the cause of the pain, and are best left alone.

"What patient can imagine that imaging studies are not likely to elucidate the cause of their backache, or that 'findings' on imaging studies are not meaningful?" Hadler said.

However, this and other studies suggest that, when faced with low back pain, less is sometimes more, Hadler told Reuters Health.

For instance, although more people in the rapid MRI group underwent back surgery, one year later, both groups were doing equally well.

"There is absolutely no data to support the assertion that surgery of any sort will alter the natural history of regional low back pain," Hadler said.