The clinical significance of the high-intensity zone on lumbar spine magnetic resonance imaging.
STUDY DESIGN: Prospective observational study of anular tears, diagnosed by a high-intensity zone within the anulus on lumbar spine magnetic resonance imaging, and correlation with the clinical features. OBJECTIVES: To assess the prevalence of high-intensity zones in patients who are investigated for back and leg pain and to determine whether there are clinical features that can be used for diagnosis of the presence of a high-intensity zone. SUMMARY OF BACKGROUND DATA: Results in previous studies have shown that the presence of a high-intensity zone is associated with reproduction of a patient's pain on stress discography. Neural compression on magnetic resonance imaging has been shown to be associated with back pain, but to date, no study has correlated the presence of a high-intensity zone with the clinical features. METHODS: The lumbar spine magnetic resonance images in 156 patients in whom back and leg pain were investigated were analyzed for the presence and appearances of high-intensity zones. The clinical features of those patients with a high-intensity zone but with no evidence of neural compression on magnetic resonance imaging were analyzed by t test and X2 test. RESULTS: A high-intensity zone occurred in patients at a prevalence of 45.5% and usually occurred posteriorly (77%) and posterolaterally (22%) within the anulus. There were no features within the history, functional disability questionnaire, or physical examination that aided in a clinical diagnosis of those patients with a high-intensity zone. CONCLUSIONS: A high-intensity zone is a common finding in patients in whom low back and leg pain are investigated, but the presence of a high-intensity zone does not define a group of patients with particular clinical features.