"Coupling high resolution bone imaging with micro finite element analysis to assess local bone adaptation – insights from the mouse tibia loading model"

Prof. Peter Pivonka (details) is Chair of Biomedical Engineering and Spinal Disorders at Queensland University of technology in Brisbane, Australia.

Abstract of his guest lecture:

Bone tissue is able to respond to external mechanical loading by adapting its structure and mass to stresses and strains induced by this load [1]. Micro-CT is currently the gold standard when assessing the effect of mechanical loading on bone structure. Imaging is generally performed ex-vivo, after sacrificing the animal at the end of the mechanical loading period (end-point imaging). Bone quantities of the entire cross section are generally computed and used for statistical analyses to compare the loaded limb with the contralateral (control) limb. However, using this methodology the local bone adaptation response on the same limb cannot be assessed.To follow local bone adaptation over time, in-vivo, longitudinal imaging procedures have been developed in combination with image co-registration algorithms. However, these protocols present several downsides, such as: excessive exposure of the animal to high radiation and anaesthesia, and large amount of data accumulation. The aim of the current study was to extend previously obtained whole cortical bone adaptation data [2] with respect to analysing local bone adaptation responses in different cortical bone regions. To do this a novel methodology based on image analysis was developed to quantify changes of cortical thickness due to different applied loads in female C57BL/6 micebased on end-point imaging data from the study of Sugiyama et al [2]. Furthermore, micro finite element analyses were performed in order to assess whether the local changes in cortical thickness are correlated with respective mechanical quanties such as stres, strain and strain energy density.

[1] Frost H Anat Rec, 275A(2):1081-101, 2003

[2] Sugiyama T et al. JBMR,27:1784-1793, 2012