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Title:

Similarities and differences in the mass-structure scaling relations of the trabecular bone taken from different locations in the femur

Document type:
Proceedings Paper
Author(s):
Raeth, Christoph; Baum, Thomas; Sidorenko, Irina; Monetti, Roberto; Eckstein, Felix; Matsuura, Maiko; Lochmueller, Eva-Maria; Zysset, Philippe K.; Bauer, Jan
Abstract:
According to Wolff's law bone remodels in response to the mechanical stresses it experiences so as to produce a minimal-weight structure that is adapted to its applied stresses. Consequently, the inner bone structure should show signs of adaptation to external forces acting on the bone. To test this paradigm, we investigate the relations between bone volume and structure for the trabecular bone using 3D mu CT images taken from two different sites in the femur in vitro, namely from the femoral neck (88 specimens) and femoral trochanter (126 specimens). We determine the local structure of the trabecular network as well as its alignment with the direction of the external force acting on the bone by calculating isotropic (alpha) and anisotropic scaling indices (alpha(z)). Comparing global structure measures derived from the scaling indices (mean, variance) with the bone mass (BV/TV) we find that all correlations obey very accurately power laws with scaling exponents of 0.48 and 0.45 (), -1.45 and -1.59 (var(alpha)), 0.50 and 0.44 () and -1,47 and -1.32 (var(alpha(z))) (neck and trochanter respectively). Thus, the relations for the isotropic scaling indices turn out to be site-independent, albeit the mechanical stress to which the femoral neck is exposed is much larger than that for the trochanter. We find, however, differences in the degree of alignment of the trabeculae as reflected by the moments of the distribution of the anisotropic scaling indices. In summary, the mass-structure scaling relations of the bone probes taken from the two different sites of the femur show surprisingly small variations. Thus, a naive interpretation of Wolff's law may not universally valid.
Keywords:
Osteoporosis; femur; trabecular bone; Wolff's law; scaling indices
Editor:
Molthen, RC; Weaver, JB
Book / Congress title:
MEDICAL IMAGING 2012: BIOMEDICAL APPLICATIONS IN MOLECULAR, STRUCTURAL, AND FUNCTIONAL IMAGING
Congress (additional information):
Conference on Medical Imaging - Biomedical Applications in Molecular, Structural and Functional Imaging, San Diego, CA, FEB 05-07, 2012
Volume:
8317
Organization:
SPIE; Agilent Technol; Diamond SA; DQE Instruments Inc; eMagin; Isuzu Glass Co Ltd; Medtron Inc; Ocean Thin Films Inc
Publisher:
SPIE-INT SOC OPTICAL ENGINEERING
Publisher address:
1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA
Year:
2012
Print-ISBN:
978-0-8194-8966-1
Bookseries title:
Proceedings of SPIE
Language:
English
Fulltext / DOI:
doi:10.1117/12.911815
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