Scaling index method: A novel nonlinear technique for the analysis of high-resolution MRI of human bones

The scaling index method (SIM) is a novel non-linear technique to extract structural information from arbitrary data sets. The tomographic images of a three dimensional object can be interpreted as a pixel distribution in a four dimensional space. The SIM provides a distribution of pointwise dimensions which characterizes the structural information of images. The SIM is applied to high resolution magnetic resonance images of human spinal and femoral bone specimens IN VITRO in order to derive a 3d non-linear texture measure which is compared to standard 2d morphometric parameters and bone mineral density in the prediction of biomechanical strength of trabecular bone. Our results show that structural non-linear parameters associated with the trabecular substructure of the bone can effectively predict the mechanical properties of trabecular bone in vitro. This indicates that the trabecular architecture contributes substantially to the biomechanical properties of the bone.