Correlation of MR lumbar spine bone marrow perfusion with bone mineral density in female subjects

PURPOSE: To prospectively assess lumbar spine bone marrow perfusion at dynamic magnetic resonance (MR) imaging and correlate perfusion with bone mineral density (BMD) in female subjects. MATERIALS AND METHODS: BMD measurement and dynamic MR imaging of the lumbar spine were performed in 69 female subjects (mean age ± standard deviation, 57 years ± 11). Subjects were stratified into premenopausal (n = 19) and postmenopausal (n = 50) groups, with the latter group including both women who were (n = 13) and women who were not (n = 37) receiving hormone replacement therapy. BMD (in grams per square centimeter) was measured with dual energy absorptiometry in the lumbar spine. Peak enhancement ratio, measured with time-signal intensity curves calculated from dynamic MR image data, represented bone marrow perfusion. Peak enhancement ratio was compared with age and BMD by using linear regression analysis and Pearson correlation. RESULTS: A significant positive correlation was found for BMD with peak enhancement ratio of lumbar vertebrae among all subjects (n = 69, r = 0.63, P < .001), all postmenopausal women (n = 50, r = 0.50, P < .001), and postmenopausal women without hormone replacement therapy (n = 37, r = 0.61, P < .001). However, the correlation between BMD and peak enhancement ratio was not significant (P > .05) in premenopausal women (n = 19) or postmenopausal women receiving hormone therapy (n = 13). Both BMD and peak enhancement ratio were inversely correlated with age (P < .001, Pearson correlation). Pearson partial correlation coefficient for peak enhancement ratio and mean in all subjects/with control for inverse correlation with age, was significant (r = 0.63, P < .001). CONCLUSION: Significant correlation was found between the peak enhancement ratio of vertebral bone marrow and BMD in postmenopausal female subjects. This result may suggest a vascular component in the pathogenesis of osteoporosis.