Assessing Methods for Characterising Local and Global Structural and Biomechanical Properties of the Trabecular Bone Network
Document type:
Review
Author(s):
Sidorenko, I.; Monetti, R.; Bauer, J.; Mueller, D.; Rummeny, E.; Eckstein, F.; Matsuura, M.; Lochmueller, E. -M.; Zysset, P.; Raeth, C.
Abstract:
We apply noval techniques, the Scaling Index Method (SIM), which reveals
local topology of the structure, and the Minkowski Functionals (MF),
which provide four global topological characteristics, to assess
strength of the trabecular network of the human bone. We compare
capabilities of these methods with the standard analysis, biomechanical
Finite Element Method (FEM) and morphological parameters, in prediction
of bone strength and fracture risk. Our study is based on a sample of
151 specimens taken from the trabecular part of human thoracic and
lumbar vertebrae in vitro, visualised using mu CT imaging (isotropic
resolution 26 mu m) and tested by uniaxial compression. The sample of
donors is heterogeneous, consisting of 58 male and 54 female cadavers
with a mean age of 80 +/- 10 years. To estimate the predictive power of
the methods, we correlate texture measures derived from mu CT images
with the maximum compressive strength (MCS) as obtained in biomechanical
tests. A linear regression analysis reveals that the failure load
estimated by FEM shows the highest correlation with MCS (Pearson's
correlation coefficient r=0.76). None of the methods in current study is
superior to the FEM: morphometric parameters give r<0.5, global
topological characteristics show r=0.73 for the first Minkowski
Functional MF1, which coincides with bone volume fraction BV/TV and
r=0.61 for the second Minkowski functional MF2, which coincides with
bone surface BS. Although scaling indices provided by SIM correlate only
moderately with MCS (r=0.55), texture measures based on the nonlinear
combination of local (SIM) and global (MF) topological characteristics
demonstrate high correlation with experimental MCS (r=0.74) and with
failure load estimated by FEM (r=0.95). Additional advantage of the
proposed texture measures is possibility to reveal the role of the
topologically different trabecular structure elements for the bone
strength.
Keywords:
High-resolution images; trabecular bone microstructure; osteoporosis;
bone strength; biomechanical properties; mechanical test; maximum
compressive strength; Finite Element Method (FEM); Minkowski Functionals
(MF); Scaling Index Method (SIM); morphological parameters; topological
properties; regression analysis