Volumetric Topological Analysis on In Vivo Trabecular Bone Magnetic Resonance Imaging

Osteoporosis is a common bone disease associated with increased risk of low-trauma fractures leading to substantial morbidity, mortality, and financial costs. Clinically, osteoporosis is defined by low bone mineral density (BMD); however, increasing evidence suggests that trabecular bone (TB) micro-architectural quality is an important determinant of bone strength and fracture risk. Recently developed volumetric topological analysis (VTA) is a unique method that characterizes individual trabeculae on the continuum between a perfect plate and a perfect rod. In this paper, an improved VTA algorithm is presented that eliminates the binarization step using fuzzy skeletonization. Its repeat scan reproducibility is evaluated for two different in vivo magnetic resonance imaging (MRI) protocols. High intra-class correlation coefficients, greater than 0.93, were observed for both the knee and the wrist MRI. The ability of the method to detect testosterone treatment effects of a two-year longitudinal study on hypogonadal men is also presented. Our method shows statistically significant improvement of TB quality as early as 6 months and the trend was observed to continue at 12 and 24 months.