Shear wave speed recovery in transient elastography and supersonic imaging using propagating fronts

McLaughlin, Joyce R.; Renzi, Daniel

doi:10.1088/0266-5611/22/2/018

Cited by 155 publications

(144 citation statements)

References 42 publications

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“…In TOF methods, it is necessary to determine the arrival time of the shear wave at each spatial location, which can be accomplished using a variety of arrival time metrics (e.g. time of peak displacement and arrival time of the leading edge of the shear wave [53,54]). Once the arrival time has been determined as a function of position, several approaches have been employed to determine the shear wave speed, including linear regression of the position versus arrival time data [53] including outlier removal with, for example, RANdom SAmple Consensus (RANSAC) [55], and arrival time surface fits that are amenable to inverse Eikonal equation solution and level set methods [54,56].…”

Section: Shear Wave Speed Reconstruction Methodsmentioning

confidence: 99%

Acoustic radiation force-based elasticity imaging methods

2011

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Conventional diagnostic ultrasound images portray differences in the acoustic properties of soft tissues, whereas ultrasound-based elasticity images portray differences in the elastic properties of soft tissues (i.e. stiffness, viscosity). The benefit of elasticity imaging lies in the fact that many soft tissues can share similar ultrasonic echogenicities, but may have different mechanical properties that can be used to clearly visualize normal anatomy and delineate pathological lesions. Acoustic radiation force-based elasticity imaging methods use acoustic radiation force to transiently deform soft tissues, and the dynamic displacement response of those tissues is measured ultrasonically and is used to estimate the tissue's mechanical properties. Both qualitative images and quantitative elasticity metrics can be reconstructed from these measured data, providing complimentary information to both diagnose and longitudinally monitor disease progression. Recently, acoustic radiation force-based elasticity imaging techniques have moved from the laboratory to the clinical setting, where clinicians are beginning to characterize tissue stiffness as a diagnostic metric, and commercial implementations of radiation forcebased ultrasonic elasticity imaging are beginning to appear on the commercial market. This article provides an overview of acoustic radiation force-based elasticity imaging, including a review of the relevant soft tissue material properties, a review of radiation force-based methods that have been proposed for elasticity imaging, and a discussion of current research and commercial realizations of radiation force based-elasticity imaging technologies.

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Section: Shear Wave Speed Reconstruction Methodsmentioning

confidence: 99%

Acoustic radiation force-based elasticity imaging methods

2011

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“…McLaughlin et al (2006a) have implemented such an approach using correlation methods on displacement datasets to determine the position of the shear wave, and shear wave speeds are estimated by inverting Eikonal equations that rely on first-order differentiation of shear wave positions through time (McLaughlin and Renzi, 2006a,b).…”

Section: Shear Wave Reconstructionmentioning

confidence: 99%

Quantifying Hepatic Shear Modulus In Vivo Using Acoustic Radiation Force

Palmeri

Wang

Dahl

et al. 2008

Ultrasound in Medicine & Biology

622

510

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The speed at which shear waves propagate in tissue can be used to quantify the shear modulus of the tissue. As many groups have shown, shear waves can be generated within tissues using focused, impulsive, acoustic radiation force excitations, and the resulting displacement response can be ultrasonically tracked through time. The goals of the work herein are two-fold: first, to develop and validate an algorithm to quantify shear wave speed from radiation force-induced, ultrasonicallydetected displacement data that is robust in the presence of poor displacement signal-to-noise ratio (SNR), and second, to apply this algorithm to in vivo datasets acquired in human volunteers in order to demonstrate the clinical feasibility of using this method to quantify the shear modulus of liver tissue in longitudinal studies. The ultimate clinical application of this work is non-invasive quantification of liver stiffness in the setting of fibrosis and steatosis.In the proposed algorithm, time to peak (TTP) displacement data in response to impulsive acoustic radiation force outside the region of excitation (ROE) are used to characterize the shear wave speed of a material, which is used to reconstruct the material's shear modulus. The algorithm is developed and validated using finite element method (FEM) simulations. Using this algorithm on simulated displacement fields, reconstructions for materials with shear moduli (μ) ranging from 1.3-5 kPa are accurate to within 0.3 kPa, while stiffer shear moduli ranging from 10-16 kPa are accurate to within 1.0 kPa. Ultrasonically tracking the displacement data, which introduces jitter in the displacement estimates, does not impede the use of this algorithm to reconstruct accurate shear moduli.Using in vivo data acquired intercostally in 20 volunteers with body mass indices (BMI) ranging from normal to obese, liver shear moduli have been reconstructed between 0.9 and 3.0 kPa, with an average precision of ±0.4 kPa. These reconstructed liver moduli are consistent with those reported in the literature (μ = 0.75-2.5 kPa) with a similar precision (±0.3 kPa). Repeated intercostal liver shear modulus reconstructions were performed on 9 different days in 2 volunteers over a 105 day period, yielding an average shear modulus of 1.9 ± 0.50 kPa (1.3-2.5 kPa) in the first volunteer, and 1.8 ± 0.4 kPa (1.1-3.0 kPa) in the second volunteer. The simulation and in vivo data to date demonstrate that this method is capable of generating accurate and repeatable liver stiffness measurements and appears promising as a clinical tool for quantifying liver stiffness.

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“…To give some background about what is known in the isotropic case, so as to contrast to the anisotropic case, we recall that previously we have established uniqueness results [10,11], and the arrival time algorithm [10,12,13], to reconstruct wave speed in isotropic media. There we show that the positions of one propagating front established the wave speed uniquely; that there is at most one pair, the shear stiffness µ and the density ρ, corresponding to a given single displacement data as a function of space and time, provided the medium is initially at rest.…”

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confidence: 99%

Anisotropy Reconstruction from Wave Fronts in Transversely Isotropic Acoustic Media

McLaughlin¹,

Renzi²,

Yoon³

2007

SIAM J. Appl. Math.

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Abstract. This paper considers an inverse problem for a transversely isotropic 3D acoustic medium where there is one preferred direction called the fiber direction along which the wave propagates fastest and there is no preferred wave propagation direction in the isotropic plane, that is the plane orthogonal to the fiber direction. In this medium the parameters to be recovered are: (1) the wave speed for a wave propagating in the direction along the fiber; (2) the wave speed for a wave propagating in any direction which is orthogonal to the fiber direction; and (3) the unit fiber direction itself. So four scalar functions are to be recovered. The data is the positions of four distinct wave fronts as the corresponding waves propagate through the medium. The mathematical relation, that is the Eikonal equation, between the wavefront locations and the four unknown functions is nonlinear. Here it is established, perhaps surprisingly, that corresponding to the given data set, there can be up to four possible solution quadruples. We present and implement an algorithm to compute each of the possible solutions and show our selection criteria to obtain the correct solution. The Eikonal equation, that relates the wave front positions to the unknown functions, is the same as one obtains for the SH wave which propagates in a linear elastic system.

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Shear wave speed recovery in transient elastography and supersonic imaging using propagating fronts

Cited by 155 publications

References 42 publications

Acoustic radiation force-based elasticity imaging methods

Acoustic radiation force-based elasticity imaging methods

Quantifying Hepatic Shear Modulus In Vivo Using Acoustic Radiation Force

Anisotropy Reconstruction from Wave Fronts in Transversely Isotropic Acoustic Media

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