Distal radius: In vivo assessment with quantitative MR imaging, peripheral quantitative CT, and dual x-ray absorptiometry

PURPOSE: To evaluate in vivo the relationship between magnetic resonance (MR) imaging relaxation time and bone mineral density (BMD) at the distal radius. MATERIALS AND METHODS: The 1/T2* MR imaging relaxation rates and dual x-ray absorptiometry (DXA) measurements were evaluated in the trabecular bone of the distal 5 cm of the radius in 14 healthy premenopausal women and 11 healthy postmenopausal women and in 11 women with osteoporosis. Trabecular and total BMD were measured with peripheral quantitative computed tomography (CT). RESULTS: In healthy women, 1/T2* values and trabecular BMD at peripheral quantitative CT were significantly correlated but 1/T2* and total BMD were not. Statistically significant (P = .03) correlations between 1/T2* and DXA were found only in the most distal area covered with DXA. The 1/T2* values were more closely correlated with age and showed higher relative annual decreases (0.47%-0.81%) than peripheral quantitative CT (0.20%-0.59%) or DXA (0.10%-0.39%). Pre- and postmenopausal healthy subjects could be distinguished only with MR imaging, and postmenopausal healthy and osteoporotic subjects only with CT and DXA. CONCLUSION: MR imaging relaxation rates correlate well with trabecular BMD in vivo.