Shear Wave Elastography Based on Noise Correlation and Time Reversal

Shear wave elastography (SWE) relies on the generation and tracking of coherent shear waves to image the tissue's shear elasticity. Recent technological developments have allowed SWE to be implemented in commercial ultrasound and magnetic resonance imaging systems, quickly becoming a new imaging modality in medicine and biology. However, coherent shear wave tracking sets a limitation to SWE because it either requires ultrafast frame rates (of up to 20 kHz), or alternatively, a phase-lock synchronization between shear wave-source and imaging device. Moreover, there are many applications where coherent shear wave tracking is not possible because scattered waves from tissue’s inhomogeneities, waves coming from muscular activity, heart beating or external vibrations interfere with the coherent shear wave. To overcome these limitations, several authors developed an alternative approach to extract the shear elasticity of tissues from a complex elastic wavefield. To control the wavefield, this approach relies on the analogy between time reversal and seismic noise cross-correlation. By cross-correlating the elastic field at different positions, which can be interpreted as a time reversal experiment performed in the computer, shear waves are virtually focused on any point of the imaging plane. Then, different independent methods can be used to image the shear elasticity, for example, tracking the coherent shear wave as it focuses, measuring the focus size or simply evaluating the amplitude at the focusing point. The main advantage of this approach is its compatibility with low imaging rates modalities, which has led to innovative developments and new challenges in the field of multi-modality elastography. The goal of this short review is to cover the major developments in wave-physics involving shear elasticity imaging using a complex elastic wavefield and its latest applications including slow imaging rate modalities and passive shear elasticity imaging based on physiological noise correlation.

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Lorentz force induced shear waves for magnetic resonance elastography applications

Scientific Reports ◽

10.1038/s41598-021-91895-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Guillaume Flé ◽

Guillaume Gilbert ◽

Pol Grasland-Mongrain ◽

Guy Cloutier

Keyword(s):

Magnetic Resonance ◽

Shear Wave ◽

Lorentz Force ◽

Wave Attenuation ◽

Shear Waves ◽

Estimation Method ◽

Biological Tissues ◽

Magnetic Resonance Elastography ◽

Motion Generation ◽

Wave Source

AbstractQuantitative mechanical properties of biological tissues can be mapped using the shear wave elastography technique. This technology has demonstrated a great potential in various organs but shows a limit due to wave attenuation in biological tissues. An option to overcome the inherent loss in shear wave magnitude along the propagation pathway may be to stimulate tissues closer to regions of interest using alternative motion generation techniques. The present study investigated the feasibility of generating shear waves by applying a Lorentz force directly to tissue mimicking samples for magnetic resonance elastography applications. This was done by combining an electrical current with the strong magnetic field of a clinical MRI scanner. The Local Frequency Estimation method was used to assess the real value of the shear modulus of tested phantoms from Lorentz force induced motion. Finite elements modeling of reported experiments showed a consistent behavior but featured wavelengths larger than measured ones. Results suggest the feasibility of a magnetic resonance elastography technique based on the Lorentz force to produce an shear wave source.

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Breast Elasticity Imaging Techniques: Comparison of Strain Elastography and Shear-Wave Elastography in the Same Population

Ultrasound in Medicine & Biology ◽

10.1016/j.ultrasmedbio.2020.09.022 ◽

2021 ◽

Vol 47 (1) ◽

pp. 104-113

Author(s):

WanRu Jia ◽

Ting Luo ◽

YiJie Dong ◽

XiaoXiao Zhang ◽

WeiWei Zhan ◽

...

Keyword(s):

Shear Wave ◽

Imaging Techniques ◽

Shear Wave Elastography ◽

Elasticity Imaging Techniques ◽

Elasticity Imaging ◽

Strain Elastography

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Viscoelasticity Imaging of Biological Tissues and Single Cells Using Shear Wave Propagation

Frontiers in Physics ◽

10.3389/fphy.2021.666192 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hongliang Li ◽

Guillaume Flé ◽

Manish Bhatt ◽

Zhen Qu ◽

Sajad Ghazavi ◽

...

Keyword(s):

Wave Propagation ◽

Shear Wave ◽

Soft Tissues ◽

Acoustic Radiation ◽

Single Cells ◽

Shear Waves ◽

Mechanical Vibration ◽

Shear Wave Elastography ◽

Biomechanical Properties ◽

Biological Tissues

Changes in biomechanical properties of biological soft tissues are often associated with physiological dysfunctions. Since biological soft tissues are hydrated, viscoelasticity is likely suitable to represent its solid-like behavior using elasticity and fluid-like behavior using viscosity. Shear wave elastography is a non-invasive imaging technology invented for clinical applications that has shown promise to characterize various tissue viscoelasticity. It is based on measuring and analyzing velocities and attenuations of propagated shear waves. In this review, principles and technical developments of shear wave elastography for viscoelasticity characterization from organ to cellular levels are presented, and different imaging modalities used to track shear wave propagation are described. At a macroscopic scale, techniques for inducing shear waves using an external mechanical vibration, an acoustic radiation pressure or a Lorentz force are reviewed along with imaging approaches proposed to track shear wave propagation, namely ultrasound, magnetic resonance, optical, and photoacoustic means. Then, approaches for theoretical modeling and tracking of shear waves are detailed. Following it, some examples of applications to characterize the viscoelasticity of various organs are given. At a microscopic scale, a novel cellular shear wave elastography method using an external vibration and optical microscopy is illustrated. Finally, current limitations and future directions in shear wave elastography are presented.

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Characterization of porous rocks embedded with aligned fractures from shear wave responses

Geophysical Journal International ◽

10.1093/gji/ggaa294 ◽

2020 ◽

Vol 222 (3) ◽

pp. 2172-2188

Author(s):

Ding Wang ◽

Bo Li

Keyword(s):

Shear Wave ◽

Dynamic Properties ◽

Rock Fracture ◽

Shear Waves ◽

Symmetry Plane ◽

Fast Wave ◽

Porous Rocks ◽

Anisotropic Rock ◽

Vibration Direction ◽

Wave Source

SUMMARY A single shear wave passing through an elastic anisotropic rock can split into two quasi-shear waves (noted by S1 and S2) with different polarization forms if the particle vibration direction of the wave source does not lie in the symmetry plane of the rock. This study focuses on the properties of shear waves penetrating a porous rock containing a set of aligned permeable fractures. The polarization characteristics of shear waves were selected to describe the dynamic properties of the rock as they are sensitive to the parameters of fractures and saturating fluids. From a physics viewpoint, in addition to the compressional wave, the shear wave (splitting) is governed by a wave-induced fluid flow (WIFF) process due to the specific shear stress decomposition happening on the fractures. The polarization formulas of S1 and S2 were derived based on the frequency-dependent Christoffel equation, which are related to the properties of fractures, fluids and wave frequency. The influence of the properties of fractures and fluids on the velocity and attenuation anisotropies of shear waves were analysed. The results showed that the particle oscillations of two shear waves are not completely mutually orthogonal, and are affected by the pressure equilibrium magnitude between the fractures and the corresponding interconnected pores. The S2 (slow) wave (i.e. particle polarized on the plane approximately perpendicular to the fractures) is more sensitive to the saturated fluids and the WIFF process than that of the S1 (fast) wave (i.e. wave polarized on the plane approximately parallel to the fractures). A frequency factor was proposed for quantifying the effects of WIFF on shear wave polarization and attenuation. Measurements on the unique polarization and the anisotropy of shear waves can provide a generalized indicator to predict the properties of fractures and the migration of infilling fluids in the rock fracture systems.

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Converted waves in a shallow marine environment: Experimental and modeling studies

Geophysics ◽

10.1190/1.3511524 ◽

2011 ◽

Vol 76 (1) ◽

pp. T1-T11 ◽

Cited By ~ 8

Author(s):

Nihed Allouche ◽

Guy G. Drijkoningen ◽

Willem Versteeg ◽

Ranajit Ghose

Keyword(s):

Shallow Water ◽

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Shear Waves ◽

Seismic Survey ◽

Wave Source ◽

Shallow Marine ◽

Modeling Studies ◽

Water Bottom

Seismic waves converted from compressional to shear mode in the shallow subsurface can be useful not only for obtaining shear-wave velocity information but also for improved processing of deeper reflection data. These waves generated at deep seas have been used successfully in hydrocarbon exploration; however, acquisition of good-quality converted-wave data in shallow marine environments remains challenging. We have looked into this problem through field experiments and synthetic modeling. A high-resolution seismic survey was conducted in a shallow-water canal using different types of seismic sources; data were recorded with a four-component water-bottom cable. Observed events in the field data were validated through modeling studies. Compressional waves converted to shear waves at the water bot-tom and at shallow reflectors were identified. The shear waves showed distinct linear polarization in the horizontal plane and low velocities in the marine sediments. Modeling results indicated the presence of a nongeometric shear-wave arrival excited only when the dominant wavelength exceeded the height of the source with respect to the water/sediment interface, as observed in air-gun data. This type of shear wave has a traveltime that corresponds to the raypath originating not at the source but at the interface directly below the source. Thus, these shear waves, excited by the source/water-bottom coupled system, kinematically behave as if they were generated by an S-wave source placed at the water bottom. In a shallow-water environment, the condition appears to be favorable for exciting such shear waves with nongeometric arrivals. These waves can provide useful information of shear-wave velocity in the sediments.

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Quantitative Shear Elasticity Assessment of Liver Fibrosis in Rat Model with Shear Wave Elastography Base on Acoustic Radiation Force

2014 International Conference on Medical Biometrics ◽

10.1109/icmb.2014.30 ◽

2014 ◽

Cited By ~ 2

Author(s):

Haoming Lin ◽

Xin Chen ◽

Yanrong Guo ◽

Yuanyuan Shen ◽

Siping Chen

Keyword(s):

Liver Fibrosis ◽

Shear Wave ◽

Rat Model ◽

Acoustic Radiation ◽

Shear Wave Elastography ◽

Radiation Force ◽

Acoustic Radiation Force ◽

Shear Elasticity

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Three-dimensional Shear Wave Elastography Using a 2D Row Column Addressing (RCA) Array

10.1101/2021.11.10.467798 ◽

2021 ◽

Author(s):

Zhijie Dong ◽

Jihun Kim ◽

Chengwu Huang ◽

Matthew R. Lowerison ◽

Shigao Chen ◽

...

Keyword(s):

Shear Wave ◽

3D Imaging ◽

Shear Wave Elastography ◽

High Volume ◽

Clinical Translation ◽

Wave Source ◽

Shear Wave Speed ◽

External Vibration ◽

Volume Rate ◽

Wide Range

Objective: To develop a 3D shear wave elastography (SWE) technique using a 2D row column addressing (RCA) array, with either external vibration or acoustic radiation force (ARF) as the shear wave source. Impact Statement: The proposed method paves the way for clinical translation of 3D-SWE based on the 2D RCA, providing a low-cost and high volume-rate solution that is compatible with existing clinical systems. Introduction: SWE is an established ultrasound imaging modality that provides a direct and quantitative assessment of tissue stiffness, which is significant for a wide range of clinical applications including cancer and liver fibrosis. SWE requires high frame-rate imaging for robust shear wave tracking. Due to the technical challenges associated with high volume-rate imaging in 3D, current SWE techniques are typically confined to 2D. Advancing SWE from 2D to 3D is significant because of the heterogeneous nature of tissue, which demands 3D imaging for accurate and comprehensive evaluation. Methods: A 3D SWE method using a 2D RCA array was developed with a volume-rate up to 2000 Hz. The performance of the proposed method was systematically evaluated on tissue-mimicking elasticity phantoms. Results: 3D shear wave motion induced by either external vibration or ARF was successfully detected with the proposed method. Robust 3D shear wave speed maps were reconstructed for both homogeneous and heterogeneous phantoms with inclusions. Conclusion: The high volume-rate 3D imaging provided by the 2D RCA array provides a robust and practical solution for 3D SWE with a clear pathway for future clinical translation.

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Аpplication of shear wave elastography for differential diagnosis of clinical and morphological types of acute pancreatitis

Diagnostic radiology and radiotherapy ◽

10.22328/2079-5343-2021-12-3-72-79 ◽

2021 ◽

Vol 12 (3) ◽

pp. 72-79

Author(s):

T. P. Kabanenko ◽

A. A. Kinzerskiy

Keyword(s):

Acute Pancreatitis ◽

Differential Diagnosis ◽

Shear Wave ◽

Imaging Techniques ◽

Necrotizing Pancreatitis ◽

Shear Wave Elastography ◽

Control Group ◽

Elasticity Imaging Techniques ◽

Elasticity Imaging ◽

Acute Necrotizing

Introduction. The incidence of acute pancreatitis increases every year. Early diagnosis of the necrotic type of acute pancreatitis is still relevant.Purpose. To reveal the informativeness of Elasticity Imaging Techniques for differential diagnosis of clinical and morphological types of acute pancreatitis.Material and methods. Shear wave sonoelastometry (ElastPQ-pSWE) was performed for 19 patients with acute edematous pancreatitis, and 13 patients with acute necrotizing pancreatitis. The control group consisted of 30 healthy volunteers.Results. In comparison with the control group, the stiffness of the pancreatic parenchyma was 1,3 times higher in the edematous form of AP (p3=0,0013, p6=0,007, p8=0,0024) and 5,3 times in the necrotic form of AP (p3=3,3e-5, p6=8e-07, p8=7,1e-8) and amounted to 5,16±1,34 kPa and 20,55±8,39 kPa, respectively, versus 3,86±1,04 kPa.Conclusions. Elasticity Imaging Techniques with shear wave technology provides an additional criterion for differential diagnosis of clinical and morphological types of acute pancreatitis.

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