scholarly journals Supersonic Shear Wave Imaging to Assess Arterial Nonlinear Behavior and Anisotropy: Proof of Principle via Ex Vivo Testing of the Horse Aorta

2014 ◽  
Vol 6 ◽  
pp. 272586 ◽  
Author(s):  
D. A. Shcherbakova ◽  
C. Papadacci ◽  
A. Swillens ◽  
A. Caenen ◽  
S. De Bock ◽  
...  
Keyword(s):  
Shear Wave ◽  
Ex Vivo ◽  
Nonlinear Behavior ◽  
Propagation Speed ◽  
Axial Direction ◽  
Shear Wave Imaging ◽  
Tumor Diagnostics ◽  
Position Controller ◽  
Wave Imaging ◽  
Rectangular Slab

Supersonic shear wave imaging (SSI) is a noninvasive, ultrasound-based technique to quantify the mechanical properties of bulk tissues by measuring the propagation speed of shear waves (SW) induced in the tissue with an ultrasound transducer. The technique has been successfully validated in liver and breast (tumor) diagnostics and is potentially useful for the assessment of the stiffness of arteries. However, SW propagation in arteries is subjected to different wave phenomena potentially affecting the measurement accuracy. Therefore, we assessed SSI in a less complex ex vivo setup, that is, a thick-walled and rectangular slab of an excised equine aorta. Dynamic uniaxial mechanical testing was performed during the SSI measurements, to dispose of a reference material assessment. An ultrasound probe was fixed in an angle position controller with respect to the tissue to investigate the effect of arterial anisotropy on SSI results. Results indicated that SSI was able to pick up stretch-induced stiffening of the aorta. SW velocities were significantly higher along the specimen's circumferential direction than in the axial direction, consistent with the circumferential orientation of collagen fibers. Hence, we established a first step in studying SW propagation in anisotropic tissues to gain more insight into the feasibility of SSI-based measurements in arteries.

scholarly journals Smart ultrasound device for real-time myocardial stiffness quantification of the human heart

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
O Pedreira ◽  
C Papadacci ◽  
S Chatelin ◽  
M Correia ◽  
M Tanter ◽  
...  
Keyword(s):  
Real Time ◽  
Shear Wave ◽  
Acoustic Radiation ◽  
Ex Vivo ◽  
Radiation Force ◽  
Septal Wall ◽  
Shear Wave Imaging ◽  
Wave Imaging ◽  
Good Agreement

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ERC Introduction Myocardial stiffness (MS) is crucial to understand cardiac biomechanics and evaluate cardiac function. We recently demonstrated that shear wave imaging using acoustic radiation force can provide quantitative end-diastolic MS in human patients [1] . However, the dependence of shear wave velocity with myofiber orientation remained a limitation and required to perform Shear Wave Velocity (SWV) estimations from different probe orientations which is challenging in clinical practice. We propose a new approach to provide real-time quantitative assessment of MS without dependence of the probe orientation based on a dedicated smart ultrasound (US) device. Methods A new US probe was designed and manufactured to generate acoustic radiation force along the central axis and track the SWV simultaneously along three different orientations to obtain an elliptic profile of SWS. The probe was connected to dedicated electronics and software to provide real-time end-diastolic MS with ECG gating. Validation was performed on 4 in-vitro calibrated phantoms (0.92 – 1.49 – 2.58 – 3.49 m/s) and on ex vivo porcine hearts. MS along and across the fibers were compared to the values measured by conventional shear wave imaging with a linear probe mounted on a rotation motor (angular step of 10°) (Aixplorer, Supersonic imaging). Finally, the in vivo feasibility and reproducibility of measuring MS of the antero-septal wall and of the right ventricular (RV) wall was assessed transthoracically on four human volunteer . Results In vitro results on phantoms showed a good agreement with calibrated value (r2 = 0.98, std = 4.8%). Elliptic profiles on ex-vivo porcine heart showed good agreement with Aixplorer measurements acquired at different angles, with a relative difference along the long axis (LA) of: Δ=7.0%, Δ=7.1%, Δ=9% respectively for left ventricle (LV), right ventricle (RV) and septum. Finally, myocardial SWV assessment in human volunteers was obtained successfully on the RV and on the septum in late diastole. The mean MS was 1.79+/- 0.15 m/s along the fiber direction, the  fractional anisotropy (FA) was 0.25 +/- 0.06 on septal wall  in good agreement with previous results [1] and 1.06 +/- 0.11 m/s along fibers orientation and a FA of 0.27 +/- 0.08 on RV.  Finally the beat to beat reproducibility of MS measurement was estimated to be 8.22%. Conclusion The new smart US device allowed non-invasive quantification of anisotropic myocardial tissues in real time. Results showed the accuracy of the methods. This approach could offer a new clinical tool for the evaluation of the myocardium in cardiomyopathies and in heart failure patients. Abstract Figure. SWV on myocardium human volonteer

Supersonic shear wave imaging to assess arterial anisotropy: Ex-vivo testing of the horse aorta

2013 ◽  
Author(s):  
Darya Shcherbakova ◽  
Abigail Swillens ◽  
Annette Caenen ◽  
Sander De Bock ◽  
Patrick Segers ◽  
...  
Keyword(s):  
Shear Wave ◽  
Ex Vivo ◽  
Shear Wave Imaging ◽  
Wave Imaging ◽  
Ex Vivo Testing

Evaluation of the Effect of Tissue Compression on the Results of Shear Wave Elastography Measurements

2018 ◽  
Vol 40 (6) ◽  
pp. 380-393 ◽  
Author(s):  
Jaromir Vachutka ◽  
Zuzana Sedlackova ◽  
Tomas Furst ◽  
Miroslav Herman ◽  
Jan Herman ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Shear Wave ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Shear Wave Elastography ◽  
Shear Wave Imaging ◽  
Phantom Measurements ◽  
Wave Imaging ◽  
Tissue Compression

Shear wave imaging is considered to be more precise and less operator dependent when compared with strain imaging. It enables quantitative and reproducible data (Young’s modulus of the imaged tissue). However, results of shear wave imaging can be affected by a variety of different factors. The aim of this study is to evaluate the effect of the pressure applied by the ultrasound probe during examination on the measured values of Young’s modulus. The effect of the tissue compression on the results of the real-time shear wave elastography was evaluated via the gelatine phantom measurements, via the ex vivo experiments with pig liver, and via the in vivo measurements of the thyroid gland stiffness on healthy volunteers. The results of our measurements confirmed that the measured value of Young’s modulus increases with the increasing pressure applied on the imaged object. The highest increase was observed during the ex vivo experiments (400%), and the lowest increase was detected in the case of the phantom measurements (8%). A two- to threefold increase in Young’s modulus was observed between the minimum and maximum pressure in the case of the in vivo elastography measurements of thyroid gland. The Veronda-Westman theoretical model was used for the description of the tissue nonlinearity. We conclude that tissue compression by the force exerted on the probe can significantly affect the results of the real-time shear wave elastography measurements. Minimum pressure should be used when measuring the absolute value of Young’s modulus of superficial organs.

FROM THE BOREHOLE WALL INTO THE FORMATION – COMBINING BOREHOLE IMAGES WITH DEEP SHEAR WAVE IMAGING TECHNOLOGY

2019 ◽  
Author(s):  
Stefan Schimschal ◽  
Stephen Fayers ◽  
Nicklas Ritzmann ◽  
Martin Cox ◽  
Iain Whyte
Keyword(s):  
Shear Wave ◽  
Borehole Wall ◽  
Imaging Technology ◽  
Shear Wave Imaging ◽  
Wave Imaging

scholarly journals Natural shear wave imaging using vocal tract vibrations: Introducing vocal passive elastography (V-PE) to thyroid elasticity mapping

2021 ◽  
Vol 118 (2) ◽  
pp. 023702
Author(s):  
Steve Beuve ◽  
Samuel Callé ◽  
Elise Khoury ◽  
Emmanuel Gilles Simon ◽  
Jean-Pierre Remenieras
Keyword(s):  
Shear Wave ◽  
Vocal Tract ◽  
Shear Wave Imaging ◽  
Wave Imaging

A Color-Doppler Shear-Wave-Imaging Phase-reconstruction Method Using Four Color Flow Images

2016 ◽  
Vol 39 (3) ◽  
pp. 172-188
Author(s):  
Naoki Sunaguchi ◽  
Yoshiki Yamakoshi ◽  
Takahito Nakajima
Keyword(s):  
Image Quality ◽  
Shear Wave ◽  
Initial Phase ◽  
Color Doppler ◽  
Reconstruction Method ◽  
Phase Reconstruction ◽  
Color Flow ◽  
Shear Wave Imaging ◽  
Wave Imaging ◽  
Phase Map

This study investigates shear wave phase map reconstruction using a limited number of color flow images (CFIs) acquired with a color Doppler ultrasound imaging instrument. We propose an efficient reconstruction method to considerably reduce the number of CFIs required for reconstruction and compare this method with Fourier analysis-based color Doppler shear wave imaging. The proposed method uses a two-step phase reconstruction process, including an initial phase map derived from four CFIs using an advanced iterative algorithm of optical interferometry. The second step reduces phase artifacts in the initial phase map using an iterative correction procedure that cycles between the Fourier and inverse Fourier domains while imposing directional filtering and total variation regularization. We demonstrate the efficacy of this method using synthetic and experimental data of a breast phantom and human breast tissue. Our results show that the proposed method maintains image quality and reduces the number of CFIs required to four; previous methods have required at least 32 CFIs to achieve equivalent image quality. The proposed method is applicable to real-time shear wave elastography using a continuous shear wave produced by a mechanical vibrator.

Real time quantitative elastography using Supersonic Shear wave Imaging

2010 ◽  
Author(s):  
Mickael Tanter ◽  
Mathieu Pernot ◽  
Gabriel Montaldo ◽  
Jean-Luc Gennisson ◽  
Eric Bavu ◽  
...  
Keyword(s):  
Real Time ◽  
Shear Wave ◽  
Shear Wave Imaging ◽  
Wave Imaging

Suppression of the influence of surface waves on shear wave imaging for buried pipe location

2021 ◽  
pp. 104517
Author(s):  
Shuan Yan ◽  
Hongyong Yuan ◽  
Yan Gao ◽  
Boao Jin ◽  
Lizheng Deng ◽  
...  
Keyword(s):  
Surface Waves ◽  
Shear Wave ◽  
Buried Pipe ◽  
Shear Wave Imaging ◽  
Wave Imaging
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