نتایج جستجو برای: shear wave

تعداد نتایج: 280072  

Journal: :Physics in medicine and biology 2012
Kenneth Hoyt Zaegyoo Hah Chris Hazard Kevin J Parker

A novel elasticity imaging system founded on the use of acoustic radiation forces from a dual beam arrangement to generate shear wave interference patterns is described. Acquired pulse-echo data and correlation-based techniques were used to estimate the resultant deformation and to visualize tissue viscoelastic response. The use of normal versus axicon focal configurations was investigated for ...

2003
R. L. Weaver

A new test method is developed for studying mixed-mode interfacial failure of thin films using laser generated stress waves. Guided by recent parametric studies of laser-induced tensile spallation, we successfully extend this technique to achieve mixed-mode loading conditions. By allowing an initial longitudinal wave to mode convert at an oblique surface, a high amplitude shear wave is generate...

2005
G. Gogoberidze G. D. Chagelishvili R. Z. Sagdeev D. G. Lominadze

Abstract Special features of magnetohydrodynamic waves linear dynamics in smooth shear flows are studied. Quantitative asymptotic and numerical analysis are performed for wide range of system parameters when basic flow has constant shear of velocity and uniform magnetic field is parallel to the basic flow. The special features consist of magnetohydrodynamic wave mutual transformation and over-r...

2013
R. De Luca J. Fromageau H. W. Chan F. Marinozzi J. Bamber

Shear wave elastography is an innovative technique that employs one conventional focused ultrasound beam to induce shear waves and another to detect them. The final quantitative elasticity image is presented as a colour map overlaying the B-mode image. This new technique is used in combination with traditional ultrasound imaging in order to improve the specificity of distinguishing malignant an...

Journal: :Ultrasound in medicine & biology 2016
Kai Lun Cheng Young Jun Choi Woo Hyun Shim Jeong Hyun Lee Jung Hwan Baek

The goal of this study was to prospectively evaluate the diagnostic performance of Virtual Touch tissue imaging quantification (VTIQ) shear wave elastography in the discrimination of benign and malignant cervical lymph nodes in routine clinical practice. Shear wave velocity was analyzed using VTIQ in 100 patients with 100 histologically proven cervical lymph nodes. Diagnostic performance was ev...

Journal: :Muscle & nerve 2017
Jane Greening Andrew Dilley

INTRODUCTION Peripheral nerves slide and stretch during limb movements. Changes in nerve stiffness associated with such movements have not been examined in detail but may be important in understanding movement-evoked pain in patients with a variety of different musculoskeletal conditions. METHODS Shear-wave elastography was used to examine stiffness in the median and tibial nerves of healthy ...

2002
B. Kiefer L. Stixrude R. M. Wentzcovitch

[1] We calculated the elasticity of (Mg,Fe)SiO3-perovskite, using the plane-wave pseudopotential method for a pressure range that encompasses the earth’s lower mantle. Adding 25 mol% FeSiO3 to the Mg endmember decreases the shear modulus by 6% at zero pressure and by 8% at core mantle boundary pressures. The bulk modulus is less affected by iron, increasing by 2% at zero pressure and by 1% at t...

2016
Fernando Zvietcovich Jianing Yao Jannick P. Rolland Kevin J. Parker

Various types of waves are produced when a harmonic force is applied to a semi-infinite half space elastic medium. In particular, surface waves are perturbations with transverse and longitudinal components of displacement that propagate in the boundary region at the surface of the elastic solid. Shear wave speed estimation is the standard for characterizing elastic properties of tissue in elast...

2006
Joyce McLaughlin Daniel Renzi

Transient elastography and supersonic imaging are promising new techniques for characterizing the elasticity of soft tissues. Using this method, an ‘ultrafast imaging’ system (up to 10 000 frames s−1) follows in real time the propagation of a low-frequency shear wave. The displacement of the propagating shear wave is measured as a function of time and space. Here we develop a fast level set bas...

Journal: :Geophysical Research Letters 2014

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