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ABNORMAL LUMBAR MRIs ARE COMMON IN ASYMPTOMATIC PEOPLE.

Magnetic resonance imaging of the lumbar spine often detects "abnormalities" of uncertain clinical significance. These researchers report a high prevalence of abnormal MRI findings in 98 people, aged 20 to 80, who had no history of back pain.

Each of the five lumbosacral disks was examined for herniation -- specifically bulge (circumferential symmetric extension), protrusion (focal or asymmetric extension), or extrusion (more extreme extension). The 98 MRI scans were mixed with abnormal MRIs from patients with back pain to reduce bias among the interpreting radiologists. Of the asymptomatic subjects, 52 percent had at least one disk bulge, 27 percent had protrusion, and 1 percent had extrusion. Bulges were more common with advancing age, and protrusions were more common in physically active people. Abnormalities of more than one disk were found in 38 percent of subjects. Many people had other findings such as annular defects (14 percent), facet arthritis (8 percent), spondylolysis (7 percent), and spondylolisthesis (7 percent).

Comment: Because disk bulges and protrusions are so common in healthy people, their detection on MRI in patients with low-back pain may have little to do with symptoms. An editorialist therefore urges clinicians to avoid early use of MRI for most of these patients.

— AS Brett

Published in Journal Watch General Medicine July 26, 1994

Citation(s):

Deyo RA. Magnetic resonance imaging of the lumbar spine -- terrific test or tar baby. N Engl J Med 1994 Jul 14 331 115-116.

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Jensen MC et al. Magnetic resonance imaging of the lumbar spine in people without back pain. N Engl J Med 1994 Jul 14 331 69-73.

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• Medline abstract (Free)