scholarly journals Phase-Aberration Correction in Shear-Wave Elastography Imaging Using Local Speed-of-Sound Adaptive Beamforming

2021 ◽  
Vol 9 ◽  
Author(s):  
Bhaskara R. Chintada ◽  
Richard Rau ◽  
Orcun Goksel
Keyword(s):  
Shear Wave ◽  
Speed Of Sound ◽  
Soft Tissues ◽  
Imaging Modality ◽  
Plane Waves ◽  
Adaptive Beamforming ◽  
Frame Rate ◽  
Tissue Elasticity ◽  
Shear Wave Speed ◽  
Local Speed

Shear wave elasticity imaging (SWEI) is a non-invasive imaging modality that provides tissue elasticity information by measuring the travelling speed of an induced shear-wave. It is commercially available on clinical ultrasound scanners and popularly used in the diagnosis and staging of liver disease and breast cancer. In conventional SWEI methods, a sequence of acoustic radiation force (ARF) pushes are used for inducing a shear-wave, which is tracked using high frame-rate multi-angle plane wave imaging (MA-PWI) to estimate the shear-wave speed (SWS). Conventionally, these plane waves are beamformed using a constant speed-of-sound (SoS), assuming an a-priori known and homogeneous tissue medium. However, soft tissues are inhomogeneous, with intrinsic SoS variations. In this work, we study the SoS effects and inhomogeneities on SWS estimation, using simulation and phantoms experiments with porcine muscle as an abbarator, and show how these aberrations can be corrected using local speed-of-sound adaptive beamforming. For shear-wave tracking, we compare standard beamform with spatially constant SoS values to software beamforming with locally varying SoS maps. We show that, given SoS aberrations, traditional beamforming using a constant SoS, regardless of the utilized SoS value, introduces a substantial bias in the resulting SWS estimations. Average SWS estimation disparity for the same material was observed over 4.3 times worse when a constant SoS value is used compared to that when a known SoS map is used for beamforming. Such biases are shown to be corrected by using a local SoS map in beamforming, indicating the importance of and the need for local SoS reconstruction techniques.

A Curl-Based Approach to Ultrasound Elastography

2010 ◽  
Author(s):  
Ali Baghani ◽  
Reza Zahiri Azar ◽  
Septimiu Salcudean ◽  
Robert Rohling
Keyword(s):  
Imaging Modality ◽  
Ultrasound Elastography ◽  
Frame Rate ◽  
Tissue Elasticity ◽  
Inversion Algorithm ◽  
Direct Inversion ◽  
The Past ◽  
Important Benefit ◽  
Clinical Interest ◽  
Tissue Elastography

The past two decades have witnessed the development of a new medical imaging modality: tissue elastography. The contrast in the images produced by an elastography system is based on the tissue elasticity, hence these images are called elastograms. Tissue elasticity is of clinical interest, because it is often correlated with pathology [1]. Different approaches to tissue elastography have emerged [2, 3]. In this article we report a tissue elastography system and its implementation on an ultrasound machine which provides consistent elastograms of a commercial quality assurance elastography phantom. The system uses our previously developed high frame rate sequencing and phase compensation techniques to measure axial and lateral motions at a typical frame rate of 1.25 kHz [4]. The system uses the curl of the displacements in a direct inversion algorithm to reconstruct elasticity. The most important benefit of this method is that the obtained elastograms are not dependent on the boundary conditions or the shape, size or position of the exciter, and as a result, the elastograms have fewer artifacts originating from these factors. The curl of the displacement has been used in magnetic resonance elastography (MRE) before, together with the direct inversion of the wave equation [5] and promising results have been obtained.

Preliminary Results for Shear Wave Speed of Sound and Attenuation Coefficients from Excised Specimens of Human Breast Tissue

1990 ◽  
Vol 12 (2) ◽  
pp. 99-118 ◽  
Author(s):  
Thomas M. Burke ◽  
Tikoes A. Blankenberg ◽  
Albert K. Q. Sui ◽  
Francis G. Blankenberg ◽  
Hanne M. Jensen
Keyword(s):  
Shear Wave ◽  
Speed Of Sound ◽  
Wave Speed ◽  
Breast Tissue ◽  
Human Breast ◽  
Human Breast Tissue ◽  
Attenuation Coefficients ◽  
Shear Wave Speed ◽  
Preliminary Results

scholarly journals Ultrasound Shear Wave Simulation of Breast Tumor Using Nonlinear Tissue Elasticity

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Dae Woo Park
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Breast Tumor ◽  
Breast Tissue ◽  
Soft Tissues ◽  
Surrounding Tissue ◽  
Tissue Elasticity ◽  
Subtle Change ◽  
Tissue Model ◽  
Shear Wave Elasticity Imaging

Shear wave elasticity imaging (SWEI) can assess the elasticity of tissues, but the shear modulus estimated in SWEI is often less sensitive to a subtle change of the stiffness that produces only small mechanical contrast to the background tissues. Because most soft tissues exhibit mechanical nonlinearity that differs in tissue types, mechanical contrast can be enhanced if the tissues are compressed. In this study, a finite element- (FE-) based simulation was performed for a breast tissue model, which consists of a circular (D: 10 mm, hard) tumor and surrounding tissue (soft). The SWEI was performed with 0% to 30% compression of the breast tissue model. The shear modulus of the tumor exhibited noticeably high nonlinearity compared to soft background tissue above 10% overall applied compression. As a result, the elastic modulus contrast of the tumor to the surrounding tissue was increased from 0.46 at 0% compression to 1.45 at 30% compression.

scholarly journals The influence of hemodialysis-induced preload changes on the propagation speed of natural shear waves

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
S Bezy ◽  
M Orlowska ◽  
A Van Craenenbroeck ◽  
M Cvijic ◽  
J Duchenne ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Wave Speed ◽  
Shear Waves ◽  
Propagation Speed ◽  
Left Ventricular ◽  
Frame Rate ◽  
High Frame Rate ◽  
Shear Wave Speed ◽  
Wave Propagation Speed

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation - Flanders (FWO) Background Shear wave elastography (SWE) is a novel ultrasound technique based on the detection of transverse waves travelling through the myocardium using high frame rate echocardiography. The propagation speed of these shear waves is dependent on the stiffness of the myocardium. Previous studies have shown the potential of SWE for the non-invasive assessment of myocardial stiffness. It is unclear, however, if preload changes lead to measurable changes in the shear wave propagation speed in the left ventricle. In patients undergoing hemodialysis, the volume status is acutely changed. In this way, the effect of preload changes on shear wave speed can be assessed. Purpose The aim of this study was to explore the influence of preload changes on end-diastolic shear wave propagation speed. Methods Until now, 6 patients (age: 80[53-85] years; female: n = 2) receiving hemodialysis treatment were included. Echocardiographic images were taken before and every hour during a 4 hour hemodialysis session. Left ventricular parasternal long-axis views were acquired with an experimental high frame rate ultrasound scanner (average frame rate: 1016[941-1310] Hz). Standard echocardiography was performed with a conventional ultrasound machine. Shear waves were visualized on tissue acceleration maps by drawing an M-mode line along the interventricular septum. Shear wave propagation speed after mitral valve closure (MVC) was calculated by measuring the slope of the wave pattern on the acceleration maps (Figure A). Results Over the course of hemodialysis, the systolic (141[135-156] mmHg vs. 165[105-176] mmHg; p = 0.35 among groups) and diastolic blood pressure (70[66-75] mmHg vs. 82[63-84] mmHg; p = 0.21 among groups), heart rate (56[54-73] bmp vs. 57[50-67] bpm; p = 0.76 among groups), E/A ratio (1.6[0.7-1.8] vs. 1.2[0.6-1.4]; p = 0.43 among groups) and E/e’ (14[9-15] vs. 9[8-13]; p = 0.24 among groups ) remained the same. The ultra-filtrated volumes are shown in Figure B. The shear wave propagation speed after MVC gradually decreased during hemodialysis (6.7[5.4-9.7] m/s vs. 4.4[3.6-9.0] m/s; p = 0.04 among groups) (Figure C). There was a moderate negative correlation between shear wave speed and the ultra-filtrated volume (r=-0.63; p < 0.01) (Figure D). Conclusion The shear wave propagation speed at MVC significantly decreased over the course of hemodialysis and correlated to the ultra-filtrated volume. These results indicate that alterations in left ventricular preload affect the speed of shear waves at end-diastole. End-diastolic shear wave speed might therefore be a potential novel parameter for the evaluation of the left ventricular filling state. More patients will be included in the future to further explore these findings. Abstract Figure.

scholarly journals Myocardial stiffness assessed by natural shear wave elastography is related to pressure-volume loop derived parameters

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
S Bezy ◽  
A Caenen ◽  
J Duchenne ◽  
M Orlowska ◽  
M Amoni ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Propagation Speed ◽  
Shear Wave Elastography ◽  
Frame Rate ◽  
Myocardial Stiffness ◽  
High Frame Rate ◽  
Shear Wave Speed ◽  
Non Invasive ◽  
Operating Chamber

Abstract Background Several cardiovascular disorders are accompanied by a stiffening of the myocardium and may result in diastolic heart failure. The non-invasive assessment of myocardial stiffness could therefore improve the understanding of the pathophysiology and guide treatment. Shear wave elastography (SWE) is a recent technique with tremendous potential for evaluating myocardial stiffness in a non-invasive way. Using high frame rate echocardiography, the propagation speed of shear waves is evaluated, which is directly related to the stiffness of the myocardium. These waves are induced by for instance mitral valve closure (MVC) and propagate throughout the cardiac muscle. However, validation of SWE against an invasive gold standard method is lacking. Purpose The aim of this study was to compare echocardiographic shear wave elastography against invasive pressure-volume loops, a gold standard reference method for assessing chamber stiffness. Methods In 15 pigs (31.2±4.1 kg) stiffness of the myocardium was acutely changed by inducing ischemia/reperfusion (I/R) injury. For this, the proximal LAD was balloon occluded for 90 minutes with subsequent reperfusion for 40 minutes. Conventional and high frame rate echocardiographic images were acquired simultaneously with pressure-volume loops during baseline conditions and after the induction of the I/R injury. Preload was reduced in order to acquire a set of pressure-volume loops to derive the end-diastolic pressure volume relation (EDPVR). From the EDPVR, the stiffness coefficient β and the operating chamber stiffness dP/dV were obtained. High frame rate echocardiographic datasets of the parasternal long axis view were acquired with an experimental ultrasound scanner (HD-PULSE) at an average frame rate of 1304±115 Hz. Tissue acceleration maps were obtained by drawing an M-mode line along the interventricular septum in order to visualize shear waves after MVC (at end-diastole). The propagation speed was assessed by semi-automatically measuring the slope (Figure A). Results I/R injury led to an elevated chamber stiffness constant β (0.09±0.03 1/ml vs. 0.05±0.01 1/ml; p<0.001) and operating chamber stiffness dP/dV (1.09±0.38 mmHg/ml vs. 0.50±0.18 mmHg/ml; p<0.01). Likewise, shear wave speed after MVC increased after the induction of the I/R injury in comparison to baseline (6.1±1.2 m/s vs. 3.2±0.8 m/s; p<0.001). Shear wave speed had a moderate positive correlation with β (r=0.63; p<0.001) (Figure B) and a strong positive correlation with dP/dV (r=0.81; p<0.001) (Figure C). Conclusion End-diastolic shear wave speed is strongly related to chamber stiffness, assessed invasively by pressure-volume loops. These results indicate that shear wave propagation speed could be used as a novel non-invasive measurement of the mechanical properties of the ventricle. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FWO - Research Foundation Flanders

scholarly journals Speed of sound and shear wave speed for calf soft tissue composition and nonlinearity assessment

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Naiara Korta Martiartu ◽  
Dominik Nakhostin ◽  
Lisa Ruby ◽  
Thomas Frauenfelder ◽  
Marga B. Rominger ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Shear Wave ◽  
Speed Of Sound ◽  
Wave Speed ◽  
Tissue Composition ◽  
Soft Tissue Composition ◽  
Shear Wave Speed

scholarly journals Limitations of Muscle Ultrasound Shear Wave Elastography for Clinical Routine—Positioning and Muscle Selection

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8490
Author(s):  
Alyssa Romano ◽  
Deborah Staber ◽  
Alexander Grimm ◽  
Cornelius Kronlage ◽  
Justus Marquetand
Keyword(s):  
Shear Wave ◽  
Biceps Brachii ◽  
Imaging Modality ◽  
Shear Wave Elastography ◽  
Mechanical Anisotropy ◽  
Tissue Elasticity ◽  
Measurement Variability ◽  
Individual Patient Level ◽  
Measurement Protocol ◽  
Paravertebral Muscles

Shear wave elastography (SWE) is a clinical ultrasound imaging modality that enables non-invasive estimation of tissue elasticity. However, various methodological factors—such as vendor-specific implementations of SWE, mechanical anisotropy of tissue, varying anatomical position of muscle and changes in elasticity due to passive muscle stretch—can confound muscle SWE measurements and increase their variability. A measurement protocol with a low variability of reference measurements in healthy subjects is desirable to facilitate diagnostic conclusions on an individual-patient level. Here, we present data from 52 healthy volunteers in the areas of: (1) Characterizing different limb and truncal muscles in terms of inter-subject variability of SWE measurements. Superficial muscles with little pennation, such as biceps brachii, exhibit the lowest variability whereas paravertebral muscles show the highest. (2) Comparing two protocols with different limb positioning in a trade-off between examination convenience and SWE measurement variability. Repositioning to achieve low passive extension of each muscle results in the lowest SWE variability. (3) Providing SWE shear wave velocity (SWV) reference values for a specific ultrasound machine/transducer setup (Canon Aplio i800, 18 MHz probe) for a number of muscles and two positioning protocols. We argue that methodological issues limit the current clinical applicability of muscle SWE.

Shear Wave Speed Ratio for evaluation of nonlinearity of soft tissues

2021 ◽  
Author(s):  
Soumya Goswami ◽  
Siladitya Khan ◽  
Fan Feng ◽  
Stephen A. McAleavey
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Soft Tissues ◽  
Speed Ratio ◽  
Shear Wave Speed

DEVELOPMENT OF A GENERIC ULTRASOUND VIBRO-ACOUSTIC IMAGING PLATFORM FOR TISSUE ELASTICITY AND VISCOSITY

2012 ◽  
Vol 05 (01) ◽  
pp. 1250002
Author(s):  
YI WANG ◽  
SIPING CHEN ◽  
TIANFU WANG ◽  
TING ZHOU ◽  
QIAOLIANG LI ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Acoustic Imaging ◽  
Phase Changes ◽  
Propagation Path ◽  
Imaging Method ◽  
Tissue Elasticity ◽  
Shear Wave Speed ◽  
Early Diagnosis Of Cancer

Tissue elasticity and viscosity are always associated with pathological changes. As a new imaging method, ultrasound vibro-acoustic imaging is developed for quantitatively measuring tissue elasticity and viscosity which have important significance in early diagnosis of cancer. This paper developed an ultrasound vibro-acoustic imaging research platform mainly consisting of excitation part and detection part. The excitation transducer was focused at one location within the medium to generate harmonic vibration and shear wave propagation, and the detection transducer was applied to detect shear wave at other locations along shear wave propagation path using pulse-echo method. The received echoes were amplified, filtered, digitized and then processed by Kalman filter to estimate the vibration phase. According to the phase changes between different propagation locations, we estimated the shear wave speed, and then used it to calculate the tissue elasticity and viscosity. Preliminary phantom experiments based on this platform show results of phantom elasticity and viscosity close to literature values. Upcoming experiments are now in progress to obtain quantitative elasticity and viscosity in vitro tissue.

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