Ultrasound shear wave elastography: numerical modeling and time-frequency analysis with an application in HIFU thermal lesion detection

10.32920/ryerson.14646879 ◽

2021 ◽

Author(s):

Pooya Sobhe Bidari

Keyword(s):

Wave Propagation ◽

Acoustic Wave ◽

Shear Wave ◽

Frequency Analysis ◽

Acoustic Wave Propagation ◽

Thermal Lesion ◽

Time Frequency Analysis ◽

Time Frequency ◽

Thermal Lesions ◽

Viscoelastic Parameters

In this work, a new numerical framework is proposed and implemented to simulate acoustic wave propagation in 3D viscoelastic heterogeneous media. The framework is based on the elastodynamic wave equation in which a 3D second-order time-domain perfectly matched layer (PML) formulation is developed to model unbounded media. The numerical framework is discretized by a finite difference formulation and its stability analysis is discussed. The proposed numerical method is capable of simulating 3D shear and longitudinal acoustic waves for arbitrary source geometries and excitations, together with arbitrary initial and boundary conditions. After validation of the framework, it was used to simulate the propagation of ultrasound shear wave in high intensity focused ultrasound (HIFU) induced thermal lesions located within soft tissue. The parameters in these simulations were obtained from standard double-indentation measurements of the viscoelastic parameters of normal and thermally coagulated chicken breast tissue samples. A HIFU system was used to induce thermal lesions in tissue. In this study, a new elastography procedure was also introduced to differentiate between the normal and HIFU induced thermal lesions. This method is based on time-frequency analysis of shear wave propagation within the tissue. In the proposed method, the Wigner-Ville distribution has been used as a time-frequency analytical technique to detect the location of shear wave propagating within the tissue, and to estimate the shear speed of the wave as well as its center frequency and attenuation coefficient. This method was applied to the acoustic wave propagation simulation results of the HIFU thermal lesion. It was finally used to estimate the local viscoelastic parameters of the medium. It was demonstrated that the proposed method is capable of differentiating the thermal lesions from the normal tissue based on their viscoelastic parameters.

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ANOMALOUS SEISMO-ACOUSTIC WAVE PROPAGATION AND DETERMINATION SOURCE OF INFRASOUND

Proceedings of the Mongolian Academy of Sciences ◽

10.5564/pmas.v52i4.871 ◽

2017 ◽

pp. 29-35

Author(s):

Bayarsaikhan Ch ◽

Tungalag L ◽

Lkhagvajav Ch ◽

Alexis Le Pichon

Keyword(s):

Wave Propagation ◽

Acoustic Wave ◽

Frequency Analysis ◽

Acoustic Signals ◽

General Analysis ◽

Acoustic Wave Propagation ◽

Speed Distribution ◽

Wide Range ◽

Seasonal Wind

The network of infrasound stations (I34MN) in Mongolia daily registers set of infrasound from various sources besides explosions. The data from explosions in mines in region and from other sources detected since 2000 to 2009 in seismic and infrasound stations is analyzed. The analysis these signals dependence of speed distribution of sound from seasonal, wind forces and direction moreover on short distances. From detected in infrasound stations (I34MN) in year 80-90 % of signals make microbaroms, the wide range of their sources is visible from the frequency analysis. From the general analysis registered seismo and acoustic signals of explosions on the seismic and infrasound networks stations miscalculate not only speeds of distribution of sounds on close distances (50-500 km), and also the speed model of atmosphere is made.

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Simulation technique and time-frequency analysis of the acoustic wave inside cancelous bone

The Journal of the Acoustical Society of America ◽

10.1121/1.4933702 ◽

2015 ◽

Vol 138 (3) ◽

pp. 1797-1797

Author(s):

Yoshiki Nagatani

Keyword(s):

Acoustic Wave ◽

Frequency Analysis ◽

Simulation Technique ◽

Time Frequency Analysis ◽

Time Frequency

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Acoustic wave propagation in a fluid‐filled borehole surrounded by a formation with stress‐relief‐induced anisotropy

Geophysics ◽

10.1190/1.1443509 ◽

1993 ◽

Vol 58 (9) ◽

pp. 1257-1269 ◽

Cited By ~ 5

Author(s):

Lasse Renlie ◽

Arne M. Raaen

Keyword(s):

Wave Propagation ◽

Acoustic Wave ◽

Shear Wave ◽

Transverse Isotropy ◽

Shear Velocity ◽

Stress Relief ◽

Stoneley Wave ◽

Acoustic Wave Propagation ◽

Damaged Zone ◽

Compressional Velocity

The stress relief associated with the drilling of a borehole may lead to an anisotropic formation in the vicinity of the borehole, where the properties in the radial direction differ from those in the axial and tangential directions. Thus, axial and radial compressional acoustic velocities are different, and similarly, the velocity of an axial shear‐wave depends on whether the polarization is radial or tangential. A model was developed to describe acoustic wave propagation in a borehole surrounded by a formation with stress‐relief‐induced radial transverse isotropy (RTI). Acoustic full waveforms due to a monopole source are computed using the real‐axis integration method, and dispersion relations are found by tracing poles in the [Formula: see text] plane. An analytic expression for the low‐frequency Stoneley wave is developed. The numerical results confirm the expectations that the compressional refraction is mainly given by the axial compressional velocity, while the shear refraction arrival is due to the shear wave with radial polarization. As a result, acoustic logging in an RTI formation, will indicate a higher [Formula: see text] ratio than that existing in the virgin formation. It also follows that the shear velocity may be a better indicator of a mechanically damaged zone near the borehole than the compressional velocity. The Stoneley‐wave velocity was found to decrease with the increasing degree of RTI.

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