Scholars@Duke
Kathryn Radabaugh Nightingale

Kathryn Radabaugh Nightingale

Theo Pilkington Distinguished Professor of Biomedical Engineering
Biomedical Engineering
Box 90281, Durham, NC 27708-0281
277 Hudson Hall Annex, Durham, NC 27708

Scholarly Works - Conferences

Volumetric Mechanical Characterization of in vivo Skeletal Muscle Assessed with 3D-Rotational Shear Wave Elasticity Imaging (3D-RSWEI)

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2025 We present a volumetric characterization method for 3D-RSWEI data in in vivo skeletal muscle, in which shear wave speeds (SWS) are quantified at multiple rotational angles through multiple axial depths within the depth-of-field. We have shown in the vastus ... Full text Cite

Characterization of SH and SV Wave Modes in a Nonlinear Elastic Solid with Uniaxial Stretch Using 3D-Rotational SWEI

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2025 We present a 3D-RSWEI characterization of a polyvinyl alcohol phantom with applied uniaxial stretch at multiple transducer tilt angles (0°, 15°, 30°, and 45°), building on previous work [1]. We have observed shear horizontal (SH) and complex shear vertical ... Full text Cite

Increasing shear wave phase velocity trajectory interrogation using curved shear wave geometries for ultrasound shear wave elasticity imaging

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2025 In this work, we introduce novel shear wave excitation techniques to interrogate a broad range of shear wave trajectories with applications towards anisotropic material characterization. The two techniques discussed in this work, fixed geometry, divergent ... Full text Cite

Characterization of Anisotropic Lattice Structured Phantoms Using 3D-Rotational Shear Wave Elasticity Imaging (3D-RSWEI)

Conference IEEE Ultrasonics Ferroelectrics and Frequency Control Joint Symposium Uffc Js 2024 Proceedings · January 1, 2024 We present a 3D-RSWEI characterization of anisotropic lattice phantoms. Shear wave speeds versus rotational angle were measured while the lattices were submerged in water and after embedding in a softer, isotropic polyvinyl alcohol cryogel. In both cases, ... Full text Cite

Multidimensional SWEI algorithms in rotationally sampled media: Assessing the accuracy of phase velocity reconstruction in transversely isotropic media

Conference IEEE Ultrasonics Ferroelectrics and Frequency Control Joint Symposium Uffc Js 2024 Proceedings · January 1, 2024 In this work we propose and validate an algorithm to estimate phase velocity in anisotropic media using 3D rotational shear wave elasticity imaging. We propose a novel spatial and temporal weighting scheme to achieve millimeter-scale spatial and millisecon ... Full text Cite

Physics-informed neural networks for modeling acoustic radiation force-induced shear wave propagation and the reconstruction of material parameters from observations

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2023 Physics-informed neural networks (PINNs) solve differential equations and give compressed, analytic solutions free of discretization. Previous work used PINNs to model shear wave propagation from a spherical Gaussian impulse in an incompressible, transvers ... Full text Cite

An Open-Source Radon-Transform Shear Wave Speed Estimator with Masking Functionality to Isolate Different Shear-Wave Modes

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2022 The Radon Transform (RT) approach is a common method used to estimate shear wave trajectory and speed in ultrasound shear wave elasticity imaging (SWEI). The RT calculates the sum of 2D spatiotemporal data amplitude under each potential linear trajectory t ... Full text Cite

On the correlation between knee flexion and 3D shear wave speed and amplitude in in vivo vastus lateralis

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2022 We are investigating the potential for shear wave elasticity imaging (SWEI) derived material parameters to serve as biomarkers for skeletal muscle health. We consider muscle as a transversely isotropic (TI) material and use rotational 3D-SWEI acquisitions ... Full text Cite

Modeling Shear Wave Propagation in an Incompressible, Transversely Isotropic Material Using Physics-Informed Neural Networks

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2022 There is increasing interest in using ultrasound shear wave elasticity imaging to study tissues described as incompressible, transversely isotropic (ITI) materials, such as skeletal muscle. In silico modeling helps us predict and understand shear wave beha ... Full text Cite

Screening and Image-Guided Targeted Biopsy of Prostate Cancer Using 3D Acoustic Radiation Force Impulse (ARFI) Imaging

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2022 We have developed a 3D acoustic radiation force impulse (ARFI) imaging system that screens for prostate cancer and provides imaging guidance for a targeted biopsy in a single clinic visit. ARFI and B-mode volumes are acquired by using a rotation stage to s ... Full text Cite

Deep neural network for multiparametric ultrasound imaging of prostate cancer

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2021 This study presents a deep neural network (DNN) for generating a multiparametric ultrasound (mpUS) volume of the prostate by combining data from acoustic radiation force impulse (ARFI) imaging, shear wave elasticity imaging (SWEI), B-mode imaging, and quan ... Full text Cite

Group Shear Wave Speed Viscoelastic Analysis using 3D Rotational Volumetric Shear Wave Imaging in Relaxed and Contracted in vivo Muscle

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2021 To characterize muscle tissue as a viscoelastic transversely isotropic material, we use rotational volumetric shear wave elasticity imaging (SWEI) and group speed viscoelastic analysis. We performed these measurements in vivo in the vastus lateralis of two ... Full text Cite

Quantification of Skeletal Muscle Fiber Orientation in 3D Ultrasound B-Modes

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2021 Skeletal muscle exhibits transverse isotropy with a symmetry axis in the muscle fiber direction. Characterization of muscle mechanical properties with ultrasound shear wave elasticity imaging requires an accurate measurement of the 3D muscle fiber orientat ... Full text Cite

Factors Affecting in vivo SH and SV Mode Wave Propagation in vastus lateralis Muscle at Varying Knee Flexion Angles Using Ultrasonic Rotational 3D SWEI

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2021 We previously have demonstrated the use of ultrasonic rotational 3D SWEI to measure all three mechanical properties necessary to fully characterize the vastus lateralis muscle in vivo as an incompressible transversely isotropic material: transverse shear m ... Full text Cite

Viscoelastic Characterization in Muscle using Group Speed Analysis and Volumetric Shear Wave Elasticity Imaging

Conference IEEE International Ultrasonics Symposium Ius · September 7, 2020 Shear wave elasticity imaging (SWEI) typically assumes a homogeneous, isotropic, elastic material to relate shear wave speed (SWS) to stiffness; however muscle is anisotropic and viscoelastic (VE). To characterize this complex tissue, we combine 3D SWEI (a ... Full text Cite

Demonstration of Complex Shear Wave Patterns in Skeletal Muscle in vivo Using 3D SWEI

Conference IEEE International Ultrasonics Symposium Ius · September 7, 2020 Shear wave elastography imaging (SWEI) of skeletal muscle has previously been used to identify speeds along and across the fibers, with limited success and low repeatability. In this work we show how a tilted configuration can be used to fully characterize ... Full text Cite

Evaluating Image Quality Improvement in Multiparametric Ultrasound Imaging of Prostate Cancer by Combining ARFI, SWEI, B-mode, and QUS

Conference IEEE International Ultrasonics Symposium Ius · September 7, 2020 This study demonstrates the application of multiparametric ultrasound (mpUS) imaging techniques for combining data from four individual modalities: acoustic radiation force impulse (ARFI) imaging, shear wave elasticity imaging (SWEI), B-mode imaging, and q ... Full text Cite

Multiparametric Ultrasound for the Targeting of Prostate Cancer using ARFI, SWEI, B-mode, and QUS

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Prostate cancer diagnosis using standard transrectal ultrasound (TRUS) and systematic biopsy is challenging. To improve the performance of TRUS imaging, we combined it with acoustic radiation force impulse (ARFI) imaging and shear wave elasticity imaging ( ... Full text Cite

Comparison of Deep Learning and Classical Image Processing for Skin Segmentation

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Skin stiffness correlates with the progression of sclerotic skin diseases. Ultrasound shear wave elasticity imaging techniques can measure skin stiffness, but an accurate skin thickness measurement is required to compute the elastic modulus. We explored di ... Full text Cite

Analysis of Factors Affecting Shear Wave Speed in in vivo Skin

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 In 10 patients with cutaneous sclerotic skin conditions, shear wave elasticity imaging (SWEI) was used to measure shear wave speed in the skin in vivo. The dermis was segmented using an thresholding-based algorithm and group speeds were found in both the d ... Full text Cite

Experimental Comparison of Diagnostic Imaging Pressure Fields through the Abdominal Wall with Water

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 We previously showed in simulations that the Mechanical Index is inaccurate for estimating peak rarefaction pressure (PRP) and can overestimates PRP by more than 40%. In this work, we created a new experimental method to measure in situ pressures when acco ... Full text Cite

Bayesian Shear Wave Speed Reconstruction with an On-Axis ARFI Prior

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Shear wave elasticity image quality can be degraded by poor signal-to-noise ratio or spatial resolution due to low shear wave amplitudes and reconstruction kernel size. A framework is presented for incorporating additional information about relative stiffn ... Full text Cite

Measuring elastic nonlinearity in a soft solid using a tilted acoustic radiation force for shear wave excitation

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Excitation of multiple wave modes using shear wave elastography can result in additional information about the tissue's material characteristics and, potentially, improve disease diagnosis. Theoretically, tilting the acoustic radiation force excitation axi ... Full text Cite

Wave Speeds and Green's Tensors for Shear Wave Propagation in Incompressible, Hyperelastic Materials with Uniaxial Stretch

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Assessing elastic material properties from shear wave propagation following an acoustic radiation force impulse (ARFI) excitation is difficult in anisotropic materials because of the complex relations among the propagation direction, shear wave polarizatio ... Full text Cite

Large Field-Of-View Shear Wave Elasticity Imaging with Combined On- and Off-Axis Stiffness Estimation for High Frame Rate Hepatic HCC Screening

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Heptaocellular carcinoma (HCC) is a commonly occurring cancer and is currently detected using B-mode ultrasound scans in at-risk patients. However, B-mode ultrasound has low sensitivity for HCC, particularly for early stage disease. Ultrasound elasticity i ... Full text Cite

Robust Model-Based Viscoelastic Characterization of QIBA Phantoms through Fractional Derivative Group Shear Wave Speeds

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 We present a technique for viscoelastic material characterization from group shear wave speeds measured at various fractional derivative orders. In this work, we fit experimental group shear wave speeds at a range of fractional derivative orders to a look ... Full text Cite

A Fully Convolutional Neural Network for Rapid Displacement Estimation in ARFI Imaging

Conference IEEE International Ultrasonics Symposium Ius · October 1, 2019 Ultrasound elasticity imaging in soft tissue with acoustic radiation force requires extracting displacement information, typically on the order of several microns, from raw data. In this work, we implement a fully convolutional neural network for ultrasoun ... Full text Cite

On the Use of Spatial Coherence for in Situ Peak Rarefaction Pressure Estimation

Conference IEEE International Ultrasonics Symposium Ius · December 17, 2018 Tissue harmonic image quality has been shown to increase with elevated pressure output. The Peak Rarefaction Pressure (PRP) for a given transmit, however, is limited by the Mechanical Index (MI) guideline. We have previously demonstrated that the MI overes ... Full text Cite

Anisotropic Constructive Shearwave Interference Measurement of Transversely Anisotropic Materials

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2018 Fibrous tissues, such as skeletal muscle, tendons, and myocardium, have been shown to support orientation-dependent shear wave propagation. It has been shown that shear waves can be induced and measured with ultrasound to assess such anisotropy. Existing m ... Full text Cite

Prostate Shear Wave Elastography: Multiresolution Reconstruction Dependence on Push Beam Spacing

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2018 This study demonstrates the implementation of a multiresolution shear wave tracking algorithm that enables elasticity imaging of prostate cancer and zonal anatomy. The combined ARFI/SWEI sequence uses closely-spaced push beams across the lateral field of v ... Full text Cite

Correlation Between 3D ARFI and Quantitative Imaging Metrics from SWEI and Multi-Parametric MRI in Vivo in Normal and Cancerous Prostate Tissue

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2018 Prostate lesions and healthy regions from 12 radical prostatectomy patients were identified in acoustic radiation force impulse (ARFI) imaging, shear wave elasticity imaging (SWEI), and multi-parametric magnetic resonance imaging (mpMRI) apparent diffusion ... Full text Cite

Large Field-of-View Shear Wave Imaging for Hepatocellular Carcinoma Screening

Conference IEEE International Ultrasonics Symposium Ius · January 1, 2018 Patients with liver cirrhosis or Hepatitis C have an increased likelihood of developing hepatocellular carcinoma (HCC) and are screened every six months with ultrasound; however, B-mode has demonstrated a low sensitivity for detecting small, early stage HC ... Full text Cite

Notice of Removal: Investigating the impact of elevated acoustic output in B-mode harmonic imaging and harmonic motion tracking

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 Harmonic imaging techniques are widely used in B-mode abdominal imaging and motion tracking in shear wave elasticity imaging (SWEI) to reduce clutter and improve data quality. Harmonic imaging can be both signal-to-noise (SNR) and penetration depth (PD) li ... Full text Cite

Comparison of SWEI methods for measuring the frequency dependent phase velocity and attenuation in viscoelastic materials

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 This study compares three analysis methods to determine the frequency dependent phase velocity c(ω) and attenuation α(ω) from shear wave propagation in viscoelastic materials following acoustic radiation force impulse excitations. The analysis methods cons ... Full text Cite

Nonlinear ultrasound propagation in homogeneous and heterogeneous media: Factors affecting the in situ Mechanical Index (MI)

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 We have previously reported increases in diagnostic shearwave and harmonic SNR using pressures that exceed the US FDA guideline for the Mechanical Index (MI). The MI is calculated using peak rarefaction pressure (PRP) measured in water with linear derating ... Full text Cite

Constructive shearwave imaging: Feasibility and improvements in SNR

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 Shear wave elasticity imaging (SWEI) measures mechanical properties of tissues and has been used to characterize tissue stiffness, but SWEI is limited by low displacement SNR in stiff media such as skin. A method for repeatable measurement of skin elastici ... Full text Cite

Group-shearwave based viscoelastic parameter estimation: Analysis of sources of bias

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 Shear Wave Elasticity Imaging is used to assess liver fibrosis, as shear wave speed (SWS) correlates with fibrosis stage. We have previously proposed a group SWS-based method to derive the tissue's stiffness (μ) and viscosity (η) using an analytic solution ... Full text Cite

Group shear wave based viscoelastic parameter estimation in SWEI: Analysis of sources of bias

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 This study assesses the reliance of group shear wave speed calculations on the spatial dependence (source geometry) of an Acoustic Radiation Force Impulse excitation in viscoelastic materials. Furthermore, this work examines the impact of motion filtering ... Full text Cite

Constructive shearwave interference (CSI): Concept and feasibility

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 This paper introduces the design of a constructive shear wave interference (CSI) probe: a hemi-torroid annular mechanical ring array with a center ultrasonic tracking element. The idea is to induce shear wave displacements in a ring, then track the resulta ... Full text Cite

Nonlinear Ultrasound Propagation in Homogeneous and Heterogeneous Media: Factors Affecting the in situ Mechanical Index (MI)

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 This study used 3D nonlinear ultrasound simulations to identify the sources of error when estimating the in situ Peak Rarefaction Pressure (PRP) as compared to linear derating in the context of the Mechanical Index (MI) measurement. We found that varying m ... Full text Cite

Notice of Removal: Comparison of methods for measuring the frequency dependent phase velocity and attenuation in viscoelastic materials

Conference IEEE International Ultrasonics Symposium Ius · October 31, 2017 Shear wave (SW) propagation in viscoelastic materials is characterized by a complex, frequency-dependent shear modulus μ(f). Measurements of μ(f) typically require Fourier transform techniques to decompose an observed SW signal into discrete frequency comp ... Full text Cite

Robust characterization of viscoelastic materials from measurements of group shear wave speeds

Conference IEEE International Ultrasonics Symposium Ius · November 1, 2016 This study describes a new method to determine the stiffness μ0 and viscosity η of viscoelastic materials by observing shear wave propagation following localized, impulsive excitations and measuring the group shear wave speeds Vdisp a ... Full text Cite

Comparison between 3D ARFI imaging and mpMRI in detecting clinically-significant prostate cancer lesions

Conference IEEE International Ultrasonics Symposium Ius · November 1, 2016 Current prostate cancer screening methods involve non-targeted needle biopsies and detection of clinically-insignificant lesions that receive excessive treatments, exposing patients to unnecessary adverse side effects and placing a burden on our health car ... Full text Cite

Dispersion analysis in skin using FEM: Characterizing the effects of the lower boundary material on the propagation of shear waves

Conference IEEE International Ultrasonics Symposium Ius · November 1, 2016 Skin represents a complex structure for the quantification of viscoelastic (VE) properties using shear waves. Wave propagation through skin has been modeled as propagating both as a Lamb wave and as a Rayleigh wave, but both assumptions are limited due to ... Full text Cite

On the feasibility of estimating ultrasonic shear wave attenuation using amplitude-based methods

Conference IEEE International Ultrasonics Symposium Ius · November 1, 2016 Human tissues are known to be viscoelastic (VE), a type of material described by two behaviors: dispersion and attenuation. Several methods have been developed to measure shear wave dispersion, but quantifying shear wave attenuation (α) has been less succe ... Full text Cite

Quantifying the benefit of elevated acoustic output in harmonic imaging

Conference 2015 IEEE International Ultrasonics Symposium Ius 2015 · November 13, 2015 Tissue harmonic imaging (THI) has been widely used in abdominal imaging due to its significant reduction in acoustic noise compared to fundamental imaging. However, THI can be both signal-to-noise ratio (SNR) and penetration-depth limited during clinical i ... Full text Cite

System dependent sources of error in time-of-flight shear wave speed measurements

Conference 2015 IEEE International Ultrasonics Symposium Ius 2015 · November 13, 2015 This work discusses eight sources of uncertainty and bias arising from system dependent parameters in ultrasound shear wave speed (SWS) measurement. Each of the eight error sources of error we have identified is discussed in the context of a linear, isotro ... Full text Cite

Measurement of the frequency dependent phase velocity and attenuation from the Fourier description of shear wave propagation: Addressing geometric spreading arising from spatially asymmetric Gaussian excitations

Conference 2015 IEEE International Ultrasonics Symposium Ius 2015 · November 13, 2015 Observations of shear wave propagation in a viscoelastic (VE) tissue are typically analyzed by assuming the wave is described as a plane wave, or as the asymptotic form of a wave expanding radially from a cylindrically symmetric source. In this study we pr ... Full text Cite

Characterizing sclerotic skin stiffness with Acoustic Radiation Force Impulse (ARFI) and Shear Wave Elasticity Imaging (SWEI)

Conference 2015 IEEE International Ultrasonics Symposium Ius 2015 · November 13, 2015 Sclerotic skin diseases are associated with inflammation and fibrosis in the dermis, and these changes in collagen content with disease progression make this pathology amenable to being characterized with Acoustic Radiation Force Impulse (ARFI) and Shear W ... Full text Cite

RSNA QIBA ultrasound shear wave speed Phase II phantom study in viscoelastic media

Conference 2015 IEEE International Ultrasonics Symposium Ius 2015 · November 13, 2015 Using ultrasonic shear wave speed (SWS) estimates has become popular to noninvasively evaluate liver fibrosis, but significant inter-system variability in liver SWS measurements can preclude meaningful comparison of measurements performed with different sy ... Full text Cite

Analyzing the impact of increasing Mechanical Index (MI) and energy deposition on shear wave speed (SWS) reconstruction in human liver

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 Shear wave elasticity imaging (SWEI) has found success in liver fibrosis staging. However, technical failure and unreliable shear wave speed (SWS) estimation have been reported to increase both with elevated patient body mass index (BMI) and in the presenc ... Full text Cite

3D in vivo ARFI imaging: Prostate cancer sensitivity

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 Imaging tools that reliably visualize prostate cancer (PCa) are increasingly needed in the urological community. The objective of this research was to evaluate the ability of Acoustic Radiation Force Impulse (ARFI) imaging to localize PCa in 29 patients wi ... Full text Cite

Dependence of shear wave spectral content on acoustic radiation force excitation duration and spatial beamwidth

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 Shear Wave Elasticity Imaging (SWEI) has become increasingly popular to non-invasively characterize liver fibrosis. Generating adequate shear wave displacements in human liver in vivo can be challenging, especially in the high Body Mass Index (BMI) populat ... Full text Cite

Estimation of model parameters characterizing dispersion in ARFI induced shear waves in in vivo human liver

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 We consider the analysis of shear wave dispersion following ARFI excitation in a cohort of 135 Non-Alcoholic Fatty Liver Disease patients traditionally characterized as 'difficult-to-image.' Three analysis methods are considered: (1) measuring k(ω) by loca ... Full text Cite

Improving the accuracy of shear wave speed reconstructions using 4D directional filters in the presence of reflection artifacts

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 Reflected waves from stiffness boundaries can lead to artifacts in shear wave speed (SWS) reconstructions. 2D directional filters are commonly used with planar imaging systems to reduce in-plane reflected waves; however SWS artifacts arise from both in and ... Full text Cite

Micro-elasticity (μ-E): CNR and resolution of acoustic radiation force impulse imaging and single- and multiple track location shear wave elasticity imaging for visualizing small targets

Conference IEEE International Ultrasonics Symposium Ius · October 20, 2014 Acoustic radiation force impulse (ARFI) imaging and shear wave elasticity imaging (SWEI) use the dynamic response of tissue to impulsive mechanical stimulus to characterize local elasticity. A variant of conventional, multiple track location SWEI (MTL-SWEI ... Full text Cite

3D elasticity imaging with acoustic radiation force

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2013 Acoustic radiation force impulse (ARFI) based elasticity imaging methods have been under development for the past 15 years, and both qualitative on-axis (ARFI imaging) and quantitative shear wave speed (SWEI) methods have been introduced into the commercia ... Full text Cite

Bayesian shear wave speed estimation for in vivo 3D imaging of the prostate

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2013 Shear wave elasticity imaging (SWEI) has shown promise for visualizing structure and pathology within multiple organs; however, due to the assumptions of time of flight algorithms, artifacts caused by reflected waves at structural boundaries may be present ... Full text Cite

RSNA/QIBA: Shear wave speed as a biomarker for liver fibrosis staging

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2013 An interlaboratory study of shear wave speed (SWS) estimation was performed. Commercial shear wave elastography systems from Fibroscan, Philips, Siemens and Supersonic Imagine, as well as several custom laboratory systems, were involved. Fifteen sites were ... Full text Cite

Characterizing expansion and stiffening of the canine liver with increasing hepatic pressure

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2012 Hepatic venous pressure is increased in advancing liver disease and is considered the primary source of of complications (such as variceal bleeding and ascites). Measurement of clinically significant increases in portal pressure is important for managing l ... Full text Cite

3D shear wave imaging of anisotropic mechanical properties of muscle using a 2D matrix array transducer

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2012 A 2D matrix array is used to monitor acoustic radiation force impulse (ARFI) induced shear wave propagation in 3D in excised canine muscle. From a single acquisition, both the shear wave phase and group velocity can be calculated within a plane of symmetry ... Full text Cite

Comparison of concurrently acquired in vivo 3D ARFI and SWEI images of the prostate

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2012 In the prostate, ARFI and SWEI imaging methods have reported that cancer and other pathologies as being stiffer than the surrounding tissue. A three-dimensional in vivo prostatic imaging system capable of concurrently acquiring ARFI and SWEI data was devel ... Full text Cite

TH‐C‐217BCD‐06: Acoustic Radiation Force Based Imaging: An Overview

Conference Medical Physics · January 1, 2012 Acoustic radiation force impulse (ARFI) based elasticity imaging methods have been under investigation in research laboratories for over 15 years. In ARFI imaging methods, temporally impulsive (i.e. < 1 msec) focused acoustic radiation force is used to mec ... Full text Cite

Methodology to register prostate B-mode and ARFI images to MR and histology

Conference IEEE International Ultrasonics Symposium Ius · December 1, 2011 Acoustic Radiation Force Impulse (ARFI) imaging is being developed for guiding needle biopsy and focal therapy of Prostate cancer (PCa). In vivo ARFI images portray internal structures in the prostate with higher contrast than matched B-mode images. Given ... Full text Cite

TU‐G‐220‐01: Quantitative Elasticity Imaging with Acoustic Radiation Force Induced Shear Waves

Conference Medical Physics · January 1, 2011 Purpose: Shear waves can be generated in soft tissues using impulsive acoustic radiation force (ARFI), and the resulting shear wave speeds (SWS) can be related to the shear moduli (G) by SWS = sqrt(G/rho). Time‐of‐flight (TOF) algorithms can be used to tra ... Full text Cite

Comparison of qualitative and quantitative acoustic radiation force based elasticity imaging methods

Conference Proceedings International Symposium on Biomedical Imaging · January 1, 2011 Acoustic radiation force based elasticity imaging methods utilize focused acoustic beams to mechanically excite tissue and ultrasonic correlation based methods to monitor the dynamic response of the tissue, which reflects the underlying tissue stiffness. B ... Full text Cite

Quantifying the impact of shear wavelength and kernel size on shear wave speed estimation

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2010 Quantitative measurements of tissue stiffness can be obtained by measuring the speed of shear waves induced in tissue by acoustic radiation force. In homogeneous media, time-of-flight (TOF) measurements of shear wave speed (SWS) ideally are independent of ... Full text Cite

Improving precision of tissue shear modulus quantification within theregion of acoustic radiation force excitation with compounded displacementestimates

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2010 The time-to-peak (TTP) displacement within the region of acoustic radiationforce excitation (ROE) is directly related to the tissue shear modulus. It haspreviously been shown that the ROE TTP can be directly converted to shearmodulus using a look-up table ... Full text Cite

Correlation between SWEI and ARFI image findings in ex vivo human prostates

Conference Proceedings IEEE Ultrasonics Symposium · January 1, 2009 Acoustic Radiation Force Impulse (ARFI) imaging has previously been used to visualize normal anatomic structures and pathologies in both ex vivo and in vivo human prostates. Based on the relative displacement amplitudes in ARFI images and comparison with h ... Full text Cite

Robust hepatic shear modulus reconstruction using acoustic radiation force and RANSAC

Conference Proceedings - IEEE Ultrasonics Symposium · January 1, 2009 Liver stiffness may be useful for the staging and management of hepatic fibrosis. Liver shear modulus can be quantified by measuring the shear wave speed (SWS) in the liver using time-of-flight (TOF) methods. In in vivo patient data, this approach is susce ... Full text Cite

Concurrent ARFI imaging and HIFU ablation using a diagnostic transducer array and ultrasound system with custom beam sequences

Conference Proceedings IEEE Ultrasonics Symposium · January 1, 2009 Background, Motivation and Objective: High-intensity focused ultrasound (HIFU) has primarily been performed using a specialized ultrasound transducer for therapy and either a separate transducer for imaging or a different imaging modality. Accurate localiz ... Full text Cite

Acoustic radiation force based quantification of tissue shear modulus within the region of excitation

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2008 The speed of shear wave propagation in tissue is directly related to the tissue's shear modulus. Shear waves can be generated in tissue using focused, impulsive, acoustic radiation force excitations. Shear modulus reconstruction has typically been performe ... Full text Cite

A combined ARFI sequence for 2D displacement imaging and shear wave velocity mapping

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2008 As pathological changes are normally accompanied with changes of mechanical properties, tissue elasticity is a potential diagnostic metric for a number of diseases. While elasticity imaging techniques have been successfully applied to delineate different t ... Full text Cite

Investigating the effects of viscosity on focused, impulsive, acoustic radiation force induced shear wave morphology

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2008 The effect of dispersion on the morphology of impulsive acoustic radiation force induced shear waves propagating in viscoelastic (VE) media is investigated. Change in shear wave morphology was quantified by calculating its spatial coherence. The magnitude ... Full text Cite

Three-dimensional acoustic radiation force impulse (ARFI) imaging of human prostates in vivo

Conference Proceedings IEEE Ultrasonics Symposium · January 1, 2008 We are investigating utilizing ARFI imaging to guide prostate needle biopsy. Our previous ex vivo study demonstrated that ARFI imaging using a VF10-5 linear array was able to visualize the internal anatomy and suspicious lesions in the prostate, which may ... Full text Cite

Transcending the traditional: Using tablet PCs to enhance engineering and computer science instruction

Conference Proceedings Frontiers in Education Conference Fie · December 1, 2007 Traditional instructional methods present many obstacles to effective teaching and learning in engineering and computer science courses. These include a reliance on text-based or static mediums to convey equation- and graphics-heavy concepts, a disconnect ... Full text Cite

Visualizing the anatomic structures of human prostates using Acoustic Radiation Force Impulse (ARFI) imaging

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2007 McNeal's zonal anatomy for prostate has been the standard anatomical model for human prostate for about 30 years. It divides a human prostate into one non-glandular zone (the anterior flbromuscular stroma), and three glandular zones (central zone (CZ), tra ... Full text Cite

Therapeutic potential metric for diagnostic transducers

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2007 The goal of this work is to develop a 'therapeutic potential' metric and experimental protocol to define the expected efficacy of commercial, diagnostic transducers for thermal therapy. Temperature rises at the transducer face were measured using thin-film ... Full text Cite

Radiation force imaging: Challenges and opportunities

Conference Progress in Biomedical Optics and Imaging Proceedings of SPIE · October 15, 2007 A number of novel imaging modalities have been developed to interrogate the mechanical properties of tissue. A subset of these methods utilize acoustic radiation force to mechanically excite tissue and form images from the local responses of tissue to thes ... Full text Cite

Transcending the traditional: Using Tablet PCs to enhance engineering and computer science instruction

Conference 2007 37TH ANNUAL FRONTIERS IN EDUCATION CONFERENCE, GLOBAL ENGINEERING : KNOWLEDGE WITHOUT BORDERS - OPPORTUNITIES WITHOUT PASSPORTS, VOLS 1- 4 · January 1, 2007 Link to item Cite

Characterizing acoustic attenuation using focused impulsive acoustic radiation force

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2006 A new method to characterize a material's attenuation using acoustic radiation force is proposed. Comparison of displacement magnitudes generated in a homogeneous material by acoustic radiation force excitations can be used to estimate the material's atten ... Full text Cite

Controlled spatio-temporal heating patterns using a commercial, diagnostic ultrasound system

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2005 Thermal ultrasound therapy is being investigated as a non-invasive surgical tool with applications in soft tissue tumor and cardiac ablation; as a method for hemostasis; and in the control of thermally-activated drug delivery vehicles. The success of local ... Full text Cite

Image processing and data acquisition optimization for Acoustic Radiation Force Impulse imaging of in vivo breast masses

Conference Progress in Biomedical Optics and Imaging Proceedings of SPIE · September 19, 2005 Acoustic Radiation Force Impulse (ARFI) imaging utilizes brief, high-energy acoustic pulses to excite tissue and ultrasonic correlation based tracking methods to monitor the resulting tissue displacement, which reflects the relative mechanical properties o ... Full text Cite

Real-time acoustic radiation force impulse imaging

Conference Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2005 Acoustic radiation force impulse (ARFI) imaging uses short duration acoustic pulses to generate and subsequently determine localized displacements in tissue. Time delay estimators, such as normalized cross correlation and phase shift estimation, form the c ... Full text Link to item Cite

Ultrasonic imaging of the mechanical properties of tissues using localized, transient acoustic radiation FORCE

Conference ICASSP IEEE International Conference on Acoustics Speech and Signal Processing Proceedings · January 1, 2005 Acoustic Radiation Force Impulse (ARFI) imaging utilizes brief, high energy, focused acoustic pulses to generate radiation force in tissue, and ultrasonic correlation-based methods to detect the resulting tissue displacements in order to image the relative ... Full text Cite

Acoustic radiation force impulse imaging of in vivo breast masses

Conference Proceedings IEEE Ultrasonics Symposium · December 1, 2004 ARFI datasets were acquired in real time to identify differentiable features between benign and malignant breast masses in ARFI images. A modified Siemens SONOLINE Antares scanner and a VF10-5 probe were programmed to implement ARFI imaging in a multi-foca ... Cite

Acoustic Radiation Force Impulse (ARFI) imaging of the gastrointestinal tract

Conference Proceedings - IEEE Ultrasonics Symposium · 2004 Currently, the evaluation of lesions in the gastrointestinal (GI) tract using ultrasound suffers from poor contrast between healthy and diseased tissue. Acoustic Radiation Force Impulse (ARFI) imaging provides information about the mechanical properties of ... Cite

Shear wave anisotropy imaging

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 Shear Wave Anisotropy Imaging is a novel method that images local variations in tissue shear wave velocity. A commercial ultrasound scanner is used to generate and track propagating shear waves. Radiation force from a brief high-energy pulse generates shea ... Cite

Shear wave anisotropy imaging

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 Shear Wave Anisotropy Imaging is a novel method that images local variations in tissue shear wave velocity. A commercial ultrasound scanner is used to generate and track propagating shear waves. Radiation force from a brief high-energy pulse generates shea ... Cite

Blind source separation-based adaptive filtering of physiological and ARFI-induced tissue, blood, and cyst fluid motion, in-vivo

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 In the context of complex tissue motion patterns including physiological and Acoustic Radiation Force Impulse (ARFI) -induced tissue, blood, and cyst fluid motion, the same adaptive blind source separation (BSS)-based filtering method is effective for four ... Cite

Thermal effects associated with acoustic radiation force impulse imaging

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 Acoustic Radiation Force Impulse (ARFI) imaging uses brief, high-intensity, focused ultrasound pulses to generate radiation force in tissue. The absorption of acoustic energy also generates tissue heating. The purpose of this work is to study the maximum a ... Cite

ARFI imaging of thermal lesions in ex vivo and in vivo soft tissues

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 The ability of ARFI imaging to monitor the ablation of soft tissues both ex vivo and in vivo was investigated. Thermal lesions were induced both in freshly excised bovine liver samples and in myocardial tissue of live sheep. While conventional sonography w ... Cite

Image reconstruction with acoustic radiation force induced shear waves

Conference Proceedings of SPIE the International Society for Optical Engineering · September 12, 2003 Acoustic radiation force may be used to induce localized displacements within tissue. This phenomenon is used in Acoustic Radiation Force Impulse Imaging (ARFI), where short bursts of ultrasound deliver an impulsive force to a small region. The application ... Full text Cite

Arterial stiffness measurements with acoustic radiation force impulse imaging

Conference Proceedings of SPIE the International Society for Optical Engineering · September 12, 2003 We have developed a new method of imaging the mechanical properties of tissues based on very brief (< 1msec) and localized applications of acoustic radiation force and the ultrasonic measurement of local tissues' responses to that force. Initial results wi ... Full text Cite

Acoustic radiation force impulse imaging: EX vivo and in vivo demonstration of transient shear wave propagation

Conference Proceedings International Symposium on Biomedical Imaging · January 1, 2002 Acoustic Radiation Force Impulse (ARFI) imaging utilizes brief, high energy, focused acoustic pulses to generate radiation force in remote locations in tissue, and conventional diagnostic ultrasound methods to detect the resulting tissue displacements in o ... Full text Cite

Acoustic remote palpation: Initial in vivo results

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 An ultrasonic method for remote palpation of tissue is under investigation. In this method, a single ultrasonic transducer array is used to both apply localized radiation forces within tissue and to track the resulting displacements. The magnitude of the t ... Cite

Finite element analysis of radiation force induced tissue motion with experimental validation

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 1999 An ultrasonic radiation force-based method for remote palpation of tissue is investigated. The use of radiation force to image tissue stiffness has been proposed by several researchers. In this paper, the potential for using a diagnostic ultrasound system ... Cite

Utilization of acoustic streaming to classify breast lesions in vivo

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 1997 Results from a clinical study in which Streaming Detection was used to successfully differentiate fluid-filled lesions (cysts) from solid lesions in the breast are presented. Streaming Detection is an ultrasonic technique in which high intensity ultrasound ... Cite

Streaming detection: improvements in sensitivity

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 1996 Streaming Detection is a new ultrasonic technique proposed to distinguish fluid-filled lesions, or cysts, from solid lesions in the breast. In this technique, high intensity ultrasound pulses are used to induce acoustic streaming in cyst fluid, and this mo ... Cite

Three-dimensional flow visualization via reconstruction from successive two-dimensional vector velocity maps

Conference Annual International Conference of the IEEE Engineering in Medicine and Biology Proceedings · December 1, 1994 A translation system has been assembled to assist in high speed acquisition of parallel planes of ultrasonic data from phantoms and human tissue. Using a previously developed system that measures two-dimensional velocities in real time by tracking speckle ... Cite

Wall filtering challenges in two-dimensional vector velocity estimation

Conference Proceedings of the IEEE Ultrasonics Symposium · December 1, 1993 To formulate a clinically viable methodology for tracking blood flow in two dimensions using ultrasound, one must address some challenges posed by the physical limitations of the imaging modality. At the frequencies of interest in medical diagnostic imagin ... Cite