Elastographie haute-résolution pour l'évaluation des propriétés élastiques de la cornée et de la peau

Abstract : This thesis presents the implementation of a high-resolution quantitative elastography technique for the assessment of the biomechanical properties of the cornea and the skin. For this purpose, the Supersonic Shear wave Imaging (SSI) method has been upgraded to high-frequency ultrasound (up to 20 MHz). The SSI elastography consists in retrieving stiffness of a medium from the speed of a shear wave propagating across this medium. In thin layered organs such as the cornea and the skin, the shear wave undergoes a guided propagation which leads to dispersive effects. Thus, a model has been developed to recover quantitatively the Young's modulus from the dispersion curves. We have then obtained elasticity maps of porcine corneas (in both ex vivo and in vivo conditions) and human dermis in vivo. These experiments have highlighted the anisotropic and non-linear elastic behavior of these tissues. Finally, we have demonstrated the feasibility of using the SSI elastography for the in vivo monitoring of the corneal stiffening induced by an ophthalmic treatment called "corneal collagen cross-linking". We have also conducted two clinical trials on the human dermis. In the first study, the elasticity changes induced by skin aging have been investigated. A second study concerns the characterization of cutaneous lesions.
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Thu-Mai Nguyen. Elastographie haute-résolution pour l'évaluation des propriétés élastiques de la cornée et de la peau. Optique [physics.optics]. Université Paris-Diderot - Paris VII, 2012. Français. ⟨pastel-00782905⟩

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