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Traitement du signal et simulations pour l'élastographie ultrasonore impulsionnelle appliquée au foie

Abstract : The assessment of liver fibrosis is an essential source of information for the clinician in the diagnosis, treatment and monitoring of chronic liver disease. Echosens provides a medical device for ultrasonic elastography called Fibroscan. This technique involves measuring the velocity of a shear wave in the liver tissue caused by mechanical stress. This shear rate is directly related to the degree of fibrosis. We initially developed numerical tools based on finite element modeling for the study of elastography experiments, in order to have observations in controlled experimental conditions. In a second part, we were interested in real-time pre-processing of ultrasound backscattered signal. Two specific applications were covered: (i) estimating the distance between the probe and the Fibroscan liver parenchyma, (ii) automatic detection of a homogeneous area of liver tissue. Finally, we analyzed in detail the ability of these spectral parameters to discriminate different stages of fibrosis according to the elasticity value . All results were generated from a cohort of 181 volunteers. In the third part, we were interested in the problem of the lack of knowledge of the viewing angle of the probe related to the direction of the propagation of the shear wave. We focused on an approach often associated with temporal reversal or matched filtering. Another way to address the problem is to use a parametric approach by maximum likelihood.
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https://pastel.archives-ouvertes.fr/pastel-00670487
Contributor : Stéphane Audière <>
Submitted on : Wednesday, February 15, 2012 - 3:10:53 PM
Last modification on : Tuesday, October 20, 2020 - 10:23:18 AM
Long-term archiving on: : Wednesday, December 14, 2016 - 6:32:24 AM

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Audière Stéphane. Traitement du signal et simulations pour l'élastographie ultrasonore impulsionnelle appliquée au foie. Traitement du signal et de l'image [eess.SP]. Télécom ParisTech, 2011. Français. ⟨pastel-00670487⟩

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