Compound quantitative ultrasonic tomography of long bones using wavelets analysis

Philippe Lasaygues (1)

1 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]

Compound Quantitative Ultrasonic Tomography (CQUT) is used to long bones imaging. In previous works, we showed that an iterative tool might be used to provide, from reflection tomography, qualitative images of the shape of the object, and to provide, from transmission tomography, quantitative images of the velocity map. Both tomographies are based on ultrasonic propagation in bones, particularly perturbed by this high-contrasted heterogeneous medium. Reflected and transmitted signal are composed of several packages of waves, which had followed various pathways within the cortical shell of long bones. Signal and image processing have a large important part in the complete process. To improve reflection tomography and shape recognition, we used a novel image-processing tool that improves the resolution and, so, the cortical thickness measurement. This image processing is very simple and allows us to initialise the transmission tomography, based on the knowledge of the geometrical properties. The procedure are also based on the knowledge of the acoustical properties of the body because the Time-Of-Flight measured on the extracted ultrasonic signal are related to the useful velocities of the ultrasonic waves throughout the shell. To optimise our signal processing, we propose a novel algorithm based on the wavelet analysis tool adapted to ultrasonic signals that allow the transmitted signals to be cleaned and filtered and the useful information to be separated from the unwanted noise.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Philippe Lasaygues. Compound quantitative ultrasonic tomography of long bones using wavelets analysis. Compound quantitative ultrasonic tomography of long bones using wavelets analysis, 2005, United States. pp.223-229, ⟨10.1007/1-4020-5721-0_24⟩. ⟨hal-00440737⟩