Comparison of techniques for estimating shear-wave velocity in arterial wall using shear-wave elastography - FEM and phantom study

Dispersion-based inversion has been proposed as a viable direction for materials characterization of arteries, allowing clinicians to better study cardiovascular conditions using shear wave elastography. However, these methods rely on a priori knowledge of the vibrational modes dominating the propagating waves induced by acoustic radiation force excitation: differences between anticipated and real modal content are known to yield errors in the inversion. We seek to improve the accuracy of this process by modeling the artery as a fluid-immersed cylindrical waveguide and building an analytical framework to prescribe radiation force excitations that will selectively excite certain waveguide modes using ultrasound acoustic radiation force. We show that all even-numbered waveguide modes can be eliminated from the arterial response to perturbation, and confirm the efficacy of this approach with in silico tests that show that odd modes are preferentially excited. Finally, by analyzing data from phantom tests, we find a set of ultrasound focal parameters that demonstrate the viability of inducing the desired odd-mode response in experiments.

Section: Introductionmentioning

confidence: 99%

Toward improved accuracy in shear wave elastography of arteries through controlling the arterial response to ultrasound perturbation in-silico and in phantoms

Hugenberg¹,

Roy²,

Harrigan³

et al. 2021

“…Many waveguide models have been developed for arterial SWE: immersed plate model (Couade et al 2010, Bernal et al 2011, Nguyen et al 2011, Jang et al 2015, Widman et al 2015, Li et al 2017a, annulus waveguide (Li et al 2017b), hollow tube waveguide (Zhang et al 2005, Flamini et al 2015, fluid-filled tube (Flamini et al 2015, Lin et al 2015, immersed fluid-filled 3D finite element model (Dutta et al 2015), immersed fluid-filled SAFE models (Astaneh et al 2017. These models can be used to estimate modulus from wave propagation measurements.…”

Section: Introductionmentioning

confidence: 99%

Full waveform inversion for arterial viscoelasticity

Roy

Guddati

2023

Objective: Arterial viscosity is emerging as an important biomarker, in addition to the widely used arterial elasticity. This paper presents an approach to estimate arterial viscoelasticity using shear wave elastography (SWE). Approach: While dispersion characteristics are often used to estimate elasticity from SWE data, they are not sufficiently sensitive to viscosity. Driven by this, we develop a full waveform inversion (FWI) methodology, based on directly matching predicted and measured wall velocity in space and time, to simultaneously estimate both elasticity and viscosity. Specifically, we propose to minimize an objective function capturing the correlation between measured and predicted responses of the anterior wall of the artery. Results: The objective function is shown to be well-behaving (generally convex), leading us to effectively use gradient optimization to invert for both elasticity and viscosity. The resulting methodology is verified with synthetic data polluted with noise, leading to the conclusion that the proposed FWI is effective in estimating arterial viscoelasticity. Significance: Accurate estimation of arterial viscoelasticity, not just elasticity, provides a more precise characterization of arterial mechanical properties, potentially leading to a better indicator of arterial health.

“…Early models were focused on the simplification of geometric complexities leading to analytical solutions, with later models focused on both analytical and computational techniques. Some of the existing analytical models include, plate (Couade et al 2010, Bernal et al 2011, Nguyen et al 2011, Jang et al 2015, Widman et al 2015, Li et al 2017a, hollow tube (Zhang et al 2005, Flamini et al 2015, and fluid-filled tube (Flamini et al 2015, Lin et al 2015. A more detailed three-dimensional finite element model is utilized in Dutta et al (2015).…”

Section: Introductionmentioning

confidence: 99%

Multimodal guided wave inversion for arterial stiffness: methodology and validation in phantoms

Roy

Urban

et al. 2021

Arterial stiffness is an important biomarker for many cardiovascular diseases. Shear wave elastography is a recent technique aimed at estimating local arterial stiffness using guided wave inversion (GWI), i.e. matching the computed and measured wave dispersion. This paper develops and validates a new GWI approach by synthesizing various recent observations and algorithms: (a) refinements to signal processing to obtain more accurate experimental dispersion curves; (b) an efficient forward model to compute theoretical dispersion curves for immersed, incompressible cylindrical waveguides; (c) an optimization framework based on the recent observation that the measured dispersion curve is multimodal, i.e. it matches for not one but two different wave modes in two different frequency ranges. The resulting inversion approach is validated using extensive experimental data from rubber tube phantoms, not only for modulus estimation but also to simultaneously estimate modulus and wall thickness. The observations indicate that the modulus estimates are best performed with the information on wall thickness. The approach, which takes less than half a minute to run, is shown to be accurate, with the modulus estimated with less than 4% error for 70% of the experiments.