This project aims to develop a new method for characterizing the function of motor units (groups of muscle fibers connected to a motor neuron). The intended applications include improving the diagnosis of neurodegenerative diseases that alter motor unit phenotypes. To achieve this, we employ ultrafast ultrasound Doppler-based techniques and mechanical modeling to characterize fiber motion during stimulated contractions, both in humans and in animal models.
Bone QUS (Quantitative Ultrasound) and Imaging
I have contributed to the development of in vivo cortical bone characterization tools, using axial transmission techniques, through transmission and pulse-echo methods, and cortical bone imaging approaches. The primary application is the diagnosis of osteoporosis
Bone Biomechanics and Orthopaedics
I have developed models of cortical bone elastic properties, in particular to assess how anisotropic elasticity varies with pore network parameters or mineralization. Experimental data, notably obtained with Resonant Ultrasound Spectroscopy (RUS), have validated analytical and numerical models of homogenized cortical bone elasticity. This knowledge of the values and determinants of elastic properties has been applied to the development of in vivo techniques for ultrasonic assessment bone quality, especially porosity.
In orthopaedics, uncemented hip implants require sufficient bone quality to ensure proper anchoring and long-term stability. We conducted ex vivo studies and imaging analyses to assess the clinical value of preoperative bone density measurements in predicting the success of hip arthroplasties.
Resonant Ultrasound Spectroscopy (RUS)
RUS measures the elasticity tensor of anisotropic materials. While initially designed for small, highly resonant samples, the method faced challenges with viscoelastic materials such as bone, where resonance attenuation is high. We adapted RUS for attenuating materials like bone and plastics, developed techniques suited to bone anisotropy, and automated signal processing to enable large-scale sample analysis. This method has been applied to over 200 human cortical bone samples.
Structure–Function Relationships in Mineralized Tissues
Beyond medical applications, I have contributed to biomechanical studies of mineralized tissues, focusing on structure–function relationships in several contexts: The role of sound conduction in the skull for source localization, particularly in dolphins ; Trabecular bone structure in reptiles ; Modeling bite force in vertebrates ; Characterizing mineralized cartilage in Holocephali.