 |
|
Theses
Evaluation ultrasonore de l'os cortical en transmission transverse : étude numérique et expérimentale de la propagation d'ondes circonférentielles pour la caractérisation de la résistance mécanique du col fémoral
Evaluation ultrasonore de l'os cortical en transmission transverse : étude numérique et expérimentale de la propagation d'ondes circonférentielles pour la caractérisation de la résistance mécanique du col fémoral
Abstract : Quantitative ultrasound measurements at a skeletal site can assess bone quality. Our objective is to evidence and exploit waves that propagate circumferentially in the cortical shell of the femoral neck in order to characterize hip strength. Numerical simulations of wave propagation in femoral neck cross-sections were performed to investigate the phenomena involved. It was shown that the first arriving signal (FAS) in through transmission was always associated with circumferential waves. A strong correlation between time-of-flight of the FAS (TOFFAS) and geometrical parameters related to bone strength was observed. Circumferential waves were found to be sensitive to porosity and elasticity of the cortical shell. An experimental ultrasonic set-up was designed to investigate the relationship between TOFFAS and the bone strength obtained by mechanical testing. A first series of measurements on nine samples showed that TOFFAS can predict proximal femur strength (R ² = 0.79) at least as well as the reference technique (R ² = 0.78) using X-rays. This experimental setup can be optimized and combined to an existing ultrasound device dedicated to proximal femur in order to increase fracture risk prediction. We propose as a future perspective the use of DORT method to determine the phase velocity of circumferential waves in femoral neck from which geometrical and material properties of bone could be deduced.
Cited literature [91 references]
https://tel.archives-ouvertes.fr/tel-00556023
Contributor : Julien Grondin <>
Submitted on : Friday, January 14, 2011 - 7:58:40 PM
Last modification on : Thursday, December 10, 2020 - 12:30:35 PM
Long-term archiving on: : Friday, April 15, 2011 - 3:00:38 AM
Contributor : Julien Grondin <>
Submitted on : Friday, January 14, 2011 - 7:58:40 PM
Last modification on : Thursday, December 10, 2020 - 12:30:35 PM
Long-term archiving on: : Friday, April 15, 2011 - 3:00:38 AM