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Personnalisation des propriétés mécaniques de l'os vertébral à l'aide d'imagerie à basse dose d'irradiation : prédiction du risque de fracture

Abstract : Given the ageing population, osteoporosis and vertebral fractures are considered as a major public health issue. Vertebral fractures firstly arise without pain, so that two thirds of them commonly escape clinical diagnosis. The cost of preventive treatment is very high and need to identify patients with high risk. Hence, the key issue is to improve the prediction of the vertebral fractures. A low bone mineral density (BMD) assessed by DXA does not always explain prevalent fractures, suggesting that other parameters have to be taken in account. Mechanical approaches based on finite-element models have been proposed to predict strength of osteoporotic vertebrae. However, these models are based on quantitative computed tomography and cannot be used to analyse the whole spine in vivo for patients' follow-up because of the high radiation dose. Thus, the present study proposes subject-specific finite element models based on a low-dose imaging system. They compute a value of the failure load close to the real one (FMEF = 0,94 Fexp +242,6 ; r² = 0,83, IC95% = ± 674 N) with a low numeric cost (about ten minutes), thanks to the assessment of the specific 3D geometry and the specific individual vertebral bone mechanical properties. Indeed, relationships have been proposed in a first experiment, made on 19 vertebrae, to predict the spongious bone mechanical properties from the BMD assessed using the low-dose EOS® device. Moreover, given the lack of information concerning the macro-scale vertebral cortical bone mechanical properties, an original experiment has been carried out to compute the Young's modulus of a cortico-spongious region using an inverse finite-element method. Finally, mechanical tests were made on 15 vertebrae to assess failure loads in order to evaluate the prediction of the model. This work underlines the potential of low-dose X-ray devices to make subject-specific finite-element models that could be clinically used to predict vertebral fracture risk
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https://pastel.archives-ouvertes.fr/pastel-00004409
Contributor : Ecole Arts Et Métiers Paristech <>
Submitted on : Thursday, December 18, 2008 - 8:00:00 AM
Last modification on : Friday, October 23, 2020 - 4:38:21 PM
Long-term archiving on: : Friday, September 10, 2010 - 1:09:17 PM

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  • HAL Id : pastel-00004409, version 1

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Emilie Sapin. Personnalisation des propriétés mécaniques de l'os vertébral à l'aide d'imagerie à basse dose d'irradiation : prédiction du risque de fracture. Sciences de l'ingénieur [physics]. Arts et Métiers ParisTech, 2008. Français. ⟨NNT : 2008ENAM0036⟩. ⟨pastel-00004409⟩

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