Evaluation of MR Spectroscopy and Diffusion-Weighted MRI in Postmenopausal Bone Strength

To prospectively investigate the role of MR spectroscopy (MRS) and diffusion-weighted magnetic resonance imaging (DWI) in assessing vertebral marrow changes in postmenopausal women.

Fifty postmenopausal women, who underwent dual-energy x-ray absorptiometry of the spine, were divided into three bone density groups (normal, osteopenia, and osteoporosis) based on T-score. Both MRS and DWI of the L3 vertebral body were performed to calculate the marrow fat content and apparent diffusion coefficient (ADC). The results were compared between three groups and correlated with BMD.

Vertebral marrow fat content was significantly increased in the osteoporotic group when compared with that of the osteopenic group and the normal bone density group. ADC values in the osteoporotic, osteopenic, and normal bone density groups were 338, 408 and 464, respectively, with statistically significant differences (P < 0.001). A statistically significant positive correlation between T-scores and ADC existed (r=0.694, p value <0.001). The vertebral marrow fat content was negatively correlated to the bone density (r=-0.455, p< 0.001) and to marrow ADC (r= -0.302, p < 0.05).

The postmenopausal women with osteoporosis exhibited a corresponding increase in vertebral marrow fat content as the bone density decreased. Marrow fat content and ADC were related to the bone density. MRS and DWI are helpful in evaluating the bone marrow changes in postmenopausal women.