Metabolic bone disease, particularly osteoporosis, is a serious challenge to our health system. In the United States, treatment costs for osteoporosis is currently estimated at $10-$18 billion and expected to double over the next decade as the population ages. Currently, fracture risk is diagnosed by bone density measurements. Substantial improvement in the determination of fracture risk can be gained through knowledge of both bone density and trabecular bone (TB) structural integrity. The fabric tensor provides both a measure of bone density (scalar) and the structural orientation of TB (2nd-rank tensor). Magnetic resonance imaging provides a non-invasive means of examining both bone density and trabecular bone microstructure. Yet, technical limitations of in vivo MRI, the achievable signal-to-noise (SNR) and field-of view (FOV) within a reasonable scan time prevent an accurate determination of the fabric tensor. We propose that the TB fabric tensor and its structural anisotropy can be quantified in vivo, thereby improving the diagnostic sensitivity to disease progression and treatment efficacy. Our long-term specific aims include (i) implementation of parallel imaging at higher field strengths for the acquisition of a larger TB volume for improved analysis of the fabric tensor without SNR degradation, (ii) development of novel image processing techniques robust to noise and partial-voluming for the characterization of TB structure, and (iii) validation of the fabric tensor through comparison to finite-element calculations of theTB stiffness tensor from high resolution datasets. ? ? ?
| Wald, Michael J; Magland, Jeremy F; Rajapakse, Chamith S et al. (2012) Predicting trabecular bone elastic properties from measures of bone volume fraction and fabric on the basis of micromagnetic resonance images. Magn Reson Med 68:463-73 |
| Wald, Michael Jeffrey; Magland, Jeremy Franklin; Rajapakse, Chamith Sudesh et al. (2010) Structural and mechanical parameters of trabecular bone estimated from in vivo high-resolution magnetic resonance images at 3 tesla field strength. J Magn Reson Imaging 31:1157-68 |
| Liu, X Sherry; Zhang, X Henry; Rajapakse, Chamith S et al. (2010) Accuracy of high-resolution in vivo micro magnetic resonance imaging for measurements of microstructural and mechanical properties of human distal tibial bone. J Bone Miner Res 25:2039-50 |
