Can T2* relaxation time be considered as an alternative bone structural index?

Purpose: The aim of this study was to assess the skeletal status in postmenopausal women evaluating the correlation between active transverse relaxation time Τ 2 * as measured by Magnetic Resonance Imaging (MRI), and areal or apparent volumetric bone mineral density respectively as measured by Dual energy X-ray Absorptiometry (DXA) and peripheral quantitative computed tomography. Material and Methods: Τ 2 * relaxation times of the lumbar spine and tibia were estimated in 8 postmenopausal osteoporotic women [mean age: 64.9 ± 7.8 (1 S.D.) years] scanned in a 3.0 T MRI scanner, 5 postmenopausal osteoporotic women [mean age: 68.4 ± 9.1 (1 S.D.) years] scanned in a 1.5 T MRI scanner and 5 female healthy volunteers [mean age: 33.3 ± 10.4 (1 S.D.) years], scanned in both MRI scanners. Both patient and control groups performed peripheral Quantitative Computed Tomography (pQCT) of the tibia and DXA of the lumbar spine. T-test statistical analyses were performed to identify changes of measured bone density parameters and calculated Τ 2 * relaxation times between patient and healthy controls. In addition, correlations between bone mineral density parameters and Τ 2 * relaxation time were estimated. Results: Patients showed reduced bone mineral density parameters in both lumbar spine and tibia compared to controls. Additionally, correlation factors between Τ 2 * relaxation times and measured bone density parameters (Bone Mineral Density-BMD, volumetric BMD-vBMD and trabecular volumetric density-TrD) were found significant, ranging between r=-0.58 (p<0.05) to r=-0.87 (p<0.05) for both MRI scanners. Conclusions: Τ 2 * measurements could possibly assess changes in bone status related to BMD measurements between healthy premenopausal and osteoporotic postmenopausal women.