Purpose: To prospectively study the relationship among vertebral marrow fat content, marrow diffusion indexes, and marrow and erector spinae muscle perfusion indexes in female subjects with varying bone mineral density.
Materials and Methods: Institutional study approval and informed consent were obtained. Dual x-ray absorptiometry, proton magnetic resonance (MR) spectroscopy, diffusion-weighted MR imaging, and dynamic contrast material–enhanced MR imaging of the lumbar spine and erector spinae muscle were performed in 110 women (mean age, 73 years; range, 67–84 years). Marrow fat content, marrow apparent diffusion coefficient (ADC), and perfusion indexes (maximum enhancement and enhancement slope) of marrow and erector spinae muscle were compared among three bone density groups (normal, osteopenic, and osteoporotic). The t test comparisons and Pearson correlations were applied.
Results: Seven subjects were excluded, which yielded a final cohort of 103 subjects: 18 with normal bone density, 30 with osteopenia, and 55 with osteoporosis. Vertebral marrow fat content was significantly increased in the osteoporotic group (67.8% ± 8.5 [standard deviation]) when compared with that of the normal bone density group (59.2% ± 10.0, P = .002). Vertebral marrow perfusion indexes were significantly decreased in the osteoporotic group (enhancement slope, 1.10%/sec ± 0.51) compared with those of the osteopenic group (1.45%/sec ± 0.51, P = .01) and normal bone density group (1.70%/sec ± 0.52, P < .001). Erector spinae muscle perfusion indexes did not decrease as bone density decreased. The ADC of vertebral marrow did not change with bone density.
Conclusion: The subjects experienced a decrease in vertebral marrow maximum enhancement and enhancement slope and an increase in marrow fat content as bone density decreased. The reduction in perfusion indexes occurred only within the vertebral body and not in the paravertebral tissues supplied by the same artery.
© RSNA, 2006
NIH Consensus Development Panel on Osteoporosis Prevention
- 3 Osteoporosis: review of the evidence for prevention, diagnosis and treatment and cost-effectiveness analysis—introduction. Osteoporos Int 1998;8(suppl 4):S7–S80. Google Scholar
- 9 Assessment of risk fracture and its application to screening for postmenopausal osteoporosis: report of a WHO study group. World Health Organ Tech Rep Ser 1994;843:1–129. Medline, Google Scholar