Séminaire PMMH - Stefan Catheline (INSERM, Univ. Lyon1)

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1er avril 2022 11:00 » 12:00 — Salle réunion PMMH 1

Wave elastography applied to soft tissues and membrane

Elastography, sometimes referred as seismology of the human body, is an imaging modality now implemented on medical ultrasound systems, on MRI and recently in optical coherence tomography devices. It allows to measure shear wave speeds within soft tissues and gives a tomography reconstruction of the shear elasticity. The shear elasticity being the elasticity felt by fingers during palpation, elastography is thus a palpation tomography. In the first part of this presentation, a passive elastography method is described. Inspired by noise correlation seismology and time reversal, it allows to extract from natural shear waves produced in the human body by heart beatings, muscles activities, arterial pulsations, a shear wave speed estimation. Therefore, an elasticity palpation mapping with no shear wave source is conducted. A demo should be conducted as an illustration.
The second part is devoted to elastic waves on membranes. Elastic membranes are often used as didactic demonstration of gravitation from the general relativity perspective. Indeed, trajectories of rolling spheres such as billiard balls influence each other through the deformation their mass print within the membrane tissue as would the space-time curvature of gravity. The analogy is pushed here using membrane waves. This allows revisiting through membrane waves, the famous 1919 Eddington experiment that demonstrated light deviations of stars in the vicinity of the sun.

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