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Shear wave

Annette Caenen, Mathieu Pernot, Mathias Peirlinck, Luc Mertens, Abigail Swillens, Patrick Segers
Shear wave elastography (SWE) is a potential tool to non-invasively assess cardiac muscle stiffness. This study focused on the effect of the orthotropic material properties and mechanical loading on the performance of cardiac SWE, as it is known that these factors contribute to complex 3D anisotropic shear wave propagation. To investigate the specific impact of these complexities, we constructed a finite element model with an orthotropic material law subjected to different uniaxial stretches to simulate SWE in the stressed cardiac wall...
February 16, 2018: Physics in Medicine and Biology
F Giacco, L de Arcangelis, M Pica Ciamarra, E Lippiello
According to the acoustic fluidization hypothesis, elastic waves at a characteristic frequency form inside seismic faults even in the absence of an external perturbation. These waves are able to generate a normal stress which contrasts the confining pressure and promotes failure. Here, we study the mechanisms responsible for this wave activation via numerical simulations of a granular fault model. We observe the particles belonging to the percolating backbone, which sustains the stress, to perform synchronized oscillations over ellipticlike trajectories in the fault plane...
January 2018: Physical Review. E
Maggie Km Ma, Helen Kw Law, Kin Sun Tse, Kwok Wah Chan, Gary Cw Chan, Desmond Yh Yap, Maggie My Mok, Lorraine Py Kwan, Sydney Cw Tang, Bo Ying Choy, Tak Mao Chan
OBJECTIVES: To evaluate the use of shear wave elastography in assessment of kidney allograft tubulointerstitial fibrosis. METHODS: Shear wave elastography assessment was carried out by two independent operators in kidney transplant recipients who underwent allograft biopsy for clinical indications (i.e. rising creatinine >15% or proteinuria >1 g/day). Allograft biopsies were interpreted by the same pathologist according to the 2013 Banff Classification. RESULTS: A total of 40 elastography scans were carried out (median creatinine 172...
February 14, 2018: International Journal of Urology: Official Journal of the Japanese Urological Association
Michael Praktiknjo, Viktoria Krabbe, Alessandra Pohlmann, Matthias Sampels, Christian Jansen, Carsten Meyer, Christian P Strassburg, Jonel Trebicka, Maria A Gonzalez Carmona
BACKGROUND: Early information on treatment response of HCC to local ablative therapy is crucial. Elastography as a non-invasive method has recently been shown to play a potential role in distinguishing between benign and malignant liver lesions. Elastography of hepatocellular carcinoma (HCC) in early response to local ablative therapy has not been studied to date. METHODS: We prospectively included a cohort of 14 patients with diagnosis of HCC who were treated with local ablative therapy (transarterial chemoembolization, TACE and/or radiofrequency ablation, RFA)...
2018: PloS One
Guillaume Boivin, Martin Viens, Pierre Belanger
Structural health monitoring is a prominent alternative to the scheduled maintenance of safety-critical components. The nondispersive nature as well as the through-thickness mode shape of the fundamental shear horizontal guided wave mode (SH 0 ) make it a particularly attractive candidate for ultrasonic guided wave structural health monitoring. However, plane wave excitation of SH 0 at a high level of purity remains challenging because of the existence of the fundamental Lamb modes (A 0 and S 0 ) below the cutoff frequency thickness product of high-order modes...
February 10, 2018: Sensors
Mark G Alford, Luke Bovard, Matthias Hanauske, Luciano Rezzolla, Kai Schwenzer
Inferring the properties of dense matter is one of the most exciting prospects from the measurement of gravitational waves from neutron star mergers. However, it requires reliable numerical simulations that incorporate viscous dissipation and energy transport as these can play a significant role in the survival time of the post-merger object. We calculate time scales for typical forms of dissipation and find that thermal transport and shear viscosity will not be important unless neutrino trapping occurs, which requires temperatures above 10 MeV and gradients over length scales of 0...
January 26, 2018: Physical Review Letters
Samantha L Lipman, Ned C Rouze, Mark L Palmeri, Kathryn R Nightingale
Shear wave elasticity imaging (SWEI) characterizes the mechanical properties of human tissues to differentiate healthy from diseased tissue. Commercial scanners tend to reconstruct shear wave speeds for a region of interest using time-of-flight methods reporting a single shear wave speed (or elastic modulus) to the end user under the assumptions that tissue is elastic and shear wave speeds are not dependent on the frequency content of the shear waves. Human tissues, however, are known to be viscoelastic, resulting in dispersion and attenuation...
February 5, 2018: Ultrasound in Medicine & Biology
Bhillie D Luciani, David M Desmet, Amani A Alkayyali, Joshua M Leonardis, David Benjamin Lipps
Neck muscles are preferentially activated in specific force directions, but the constraints that the central nervous system considers when programming these preferred directions of muscle activity are unknown. The current study utilized ultrasound shear wave elastography (SWE) to investigate whether the material properties of the sternocleidomastoid (SCM) muscles exhibit preferred directions similar to their preferred direction of muscle activity during an isometric task. Twenty-four healthy participants matched isometric forces in 16 axial directions...
February 8, 2018: Journal of Applied Physiology
Gi Young Park, Dong Rak Kwon, Dae Gil Kwon
Congenital muscular torticollis (CMT) is characterized by shortening or excessive contraction of the sternocleidomastoid muscle (SCM). The main purpose of this study was to evaluate the feasibility of quantifying SCM stiffness using acoustic radiation force impulse (ARFI) sonoelastography in infants with CMT. Twenty infants with an SCM thickness greater than 10 mm with or without involvement of the entire SCM length (limitation of neck rotation passive range of motion [PROM]: group 1S >30°, group 1M = 15°-30°) and 12 infants with an SCM thickness smaller than 10 mm with or without involvement of any part of SCM (group 2) were included...
February 2018: Medicine (Baltimore)
Hui Liu, Guang Xu, Ming-Hua Yao, Huan Pu, Yan Fang, Li-Hua Xiang, Rong Wu
Background: To evaluate whether conventional ultrasound, elastography [conventional strain elastography of elasticity imaging, acoustic radiation force impulse induced strain elastography of virtual touch tissue imaging, and a novel two-dimensional shear wave elastography of virtual touch tissue imaging quantification] and clinicopathological factors are associated with axillary lymph node metastasis in invasive ductal breast carcinoma with sizes > 10 mm. Materials and Methods: We evaluated 150 breast lesions from 148 patients using the above methods and the clinicopathological factors...
January 5, 2018: Oncotarget
Shane Koppenhaver, Joshua Kniss, Daniel Lilley, Michael Oates, Cesar Fernández-de-Las-Peñas, Ruth Maher, Theodore Croy, Minoru Shinohara
Patients with low back pain commonly exhibit impaired morphology and function of spinal musculature that may be quantifiable using shear-wave elastography (SWE). The purpose of this study was to assess the intra-rater and test-retest reliability of SWE elasticity measures of the lumbar erector spinae and multifidus muscles during rest and differing levels of contraction in asymptomatic individuals. This single-group repeated-measures design involved a baseline measurement session and a follow-up session 3 days later...
February 2, 2018: Journal of Electromyography and Kinesiology
C R C Fontenelle, P Mannarino, F B D O Ribeiro, M A Milito, A C P Carvalho, L L Menegaldo, L F Oliveira
PURPOSE: Shear modulus (μ) is directly correlated to the tissue stiffness and can predict the tendon ultimate force to failure. With the knee extended 0° (K0), semitendinosus tendon (ST) is tensioned while patellar tendon (PT) is relaxed. At 80o , knee flexion (K80) tendons present an opposite stress pattern; however, the relation between ST and PT μ in both situations was not studied yet. METHOD: We accessed the μ of the ST and PT at 0o and 80o knee flexion by supersonic shear wave imaging (SSI) elastography from 18 healthy males...
February 7, 2018: Clinical Physiology and Functional Imaging
Takuji Iyama, Tomoaki Takata, Masahiko Koda, Satoko Fukuda, Shotaro Hoi, Yukari Mae, Takeaki Fukui, Chishio Munemura, Hajime Isomoto
PURPOSE: To investigate the association of renal elasticity to microscopic findings of nephron hypertrophy and nephrosclerosis. METHODS: Patients who underwent renal biopsy were enrolled. Renal elasticity was measured by acoustic radiation force impulse, and nephron size (glomerular volume, non-sclerotic glomerular density, and mean profile tubular area) and nephrosclerosis (globally sclerotic glomeruli and interstitial fibrosis) were estimated. Nephron hypertrophy was indicated by larger glomerular volume, larger tubular area, and lower non-sclerotic glomerular density...
February 6, 2018: Journal of Medical Ultrasonics
Rustu Turkay, Ercan Inci, Mustafa Gurkan Yenice, Volkan Tugcu
Introduction: Erectile dysfunction (ED) is a common health problem among males, and radiology has limited use in its diagnosis and treatment. Shear wave elastography (SWE) is a new sonographic technique. In this study, we examined the significance of SWE in the diagnosis of ED. Methods: The study included a total number of 70 participants. The mean age of the participants was 54.14 ± 8.03 years (range: 39 and 71 years old). We composed two groups. Group 1 had 35 patients who presented to the urology clinic in our hospital complaining of ED, and had a score of 17 or lower from the International Index of Erectile Function (IIEF) questionnaire...
August 2017: Ultrasound: Journal of the British Medical Ultrasound Society
I E Kuznetsova, I A Nedospasov, V V Kolesov, Z Qian, B Wang, F Zhu
The profiles of an acoustic field and electric potential of the forward and backward shear-horizontal (SH) acoustic waves of a higher order propagating in X-Y potassium niobate plate have been theoretically investigated. It has been shown that by changing electrical boundary conditions on a surface of piezoelectric plates, it is possible to change the distributions of an acoustic field and electric potential of the forward and backward acoustic waves. The dependencies of the distribution of a mechanical displacement and electrical potential over the plate thickness for electrically open and electrically shorted plates have been plotted...
February 1, 2018: Ultrasonics
Qiang Huan, Hongchen Miao, Faxin Li
The guided wave based inspection technique has been playing an important role in modern industries due to its capability in rapid detection of large structures. Among all the wave modes in plate-like structures, the fundamental shear horizontal wave (SH0) is of great importance since it is the unique non-dispersive mode. However, the generation and reception of SH0 wave using piezoelectrics is always a challenge. In this work, we synthesized face-shear deformation mode in a thickness-poled piezoelectric wafer and successfully excited/received SH0 wave in a thin aluminum plate...
January 31, 2018: Ultrasonics
Joline E Brandenburg, Sarah F Eby, Pengfei Song, William Bamlet, Gary C Sieck, Kai-Nan An
OBJECTIVE: A pilot study to longitudinally quantify effect of onabotulinum toxin A (BoNT-A) on passive muscle properties in children with cerebral palsy (CP) using ultrasound shear wave elastography (SWE). DESIGN: Prospective longitudinal cohort study RESULTS: Between 1 and 3 months post-BoNT-A, a significant improvement in the shear modulus of the lateral gastrocnemius was found at 10° plantar flexion (PF) (-7.57 [-10.98, -5.07], p=0.02) and 0° PF (-14.74 [-18...
February 5, 2018: American Journal of Physical Medicine & Rehabilitation
Tristan Langlais, Claudio Vergari, Raphael Pietton, Jean Dubousset, Wafa Skalli, Raphael Vialle
OBJECTIVES: In vitro studies showed that annulus fibrosus lose its integrity in idiopathic scoliosis. Shear-wave ultrasound elastography can be used for non-invasive measurement of shear-wave speed (SWS) in vivo in the annulus fibrosus, a parameter related to its mechanical properties. The main aim was to assess SWS in lumbar annulus fibrosus of scoliotic adolescents and compare it to healthy subjects. METHODS: SWS was measured in 180 lumbar IVDs (L3L4, L4L5, L5S1) of 30 healthy adolescents (13 ± 1...
February 5, 2018: European Radiology
A Hocquelet, N Frulio, G Gallo, C Laurent, P Papadopoulos, C Salut, A Denys, H Trillaud
PURPOSE: To correlate point-shear wave elastography (SWE) with liver hypertrophy after right portal vein embolization (RPVE) and to determine its usefulness in predicting postoperative liver failure in patients undergoing partial liver resection. PATIENTS AND METHODS: Point-SWE was performed the day before RPVE in 56 patients (41 men) with a median age of 66 years. The percentage (%) of future remnant liver (FRL) volume increase was defined as: %FRLpost-%FRLpre%FRLpre×100 and assessed on computed tomography performed 4 weeks after RPVE...
February 2, 2018: Diagnostic and Interventional Imaging
Tingting Qiu, Hong Wang, Jinzhen Song, Gang Guo, Yujun Shi, Yan Luo, Jibin Liu
The purpose of this study was to investigate whether ultrasound elastography reflects liver function reserve relative to liver fibrosis histology. Sixty-five New Zealand rabbits were divided into an experimental group (n = 45) and a control group (n = 20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. Point shear wave elastography and the indocyanine green (ICG) elimination test were performed for the two groups at 4-wk intervals for 56 wk...
February 2, 2018: Ultrasound in Medicine & Biology
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