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https://www.readbyqxmd.com/read/28646602/comparison-of-acoustic-radiation-force-impulse-imaging-and-strain-elastography-in-differentiating-malignant-from-benign-thyroid-nodules
#1
Fengjuan Zhang, Xinming Zhao, Ruoling Han, Min Du, Ping Li, Xiaohui Ji
OBJECTIVES: This study aimed to evaluate the diagnostic value of acoustic radiation force impulse (ARFI) imaging and strain elastography in differentiating malignant from benign thyroid nodules. METHODS: This study included 128 patients (104 female and 24 male; mean age ± standard deviation, 48 ± 11 years; range, 23-76 years) with 152 pathologically proven thyroid nodules. Conventional sonography, strain ratio (SR) of strain elastography, virtual touch tissue imaging (VTI) grade, and virtual touch tissue quantification (shear wave velocity [SWV]) from ARFI imaging data were generated for each nodule...
June 24, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/28643789/tidal-dynamics-and-mangrove-carbon-sequestration-during-the-oligo-miocene-in-the-south-china-sea
#2
Daniel S Collins, Alexandros Avdis, Peter A Allison, Howard D Johnson, Jon Hill, Matthew D Piggott, Meor H Amir Hassan, Abdul Razak Damit
Modern mangroves are among the most carbon-rich biomes on Earth, but their long-term (≥10(6) years) impact on the global carbon cycle is unknown. The extent, productivity and preservation of mangroves are controlled by the interplay of tectonics, global sea level and sedimentation, including tide, wave and fluvial processes. The impact of these processes on mangrove-bearing successions in the Oligo-Miocene of the South China Sea (SCS) is evaluated herein. Palaeogeographic reconstructions, palaeotidal modelling and facies analysis suggest that elevated tidal range and bed shear stress optimized mangrove development along tide-influenced tropical coastlines...
June 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28643136/assessment-of-liver-fibrosis-in-chronic-hepatitis-comparison-of-shear-wave-elastography-and-transient-elastography
#3
Shashi B Paul, Prasenjit Das, Mousumi Mahanta, Vishnubhatla Sreenivas, Saurabh Kedia, Nancy Kalra, Harpreet Kaur, Maneesh Vijayvargiya, Shouriyo Ghosh, Shivanand R Gamanagatti, Shalimar, Siddhartha Dutta Gupta, Subrat K Acharya
PURPOSE: To evaluate the diagnostic accuracy of shear wave elastography (SWE) and transient elastography (TE) in the evaluation of liver fibrosis in chronic hepatitis B (CHB) and C (CHC) patients taking liver biopsy as gold standard. METHODS: Ethics committee approved this prospective cross-sectional study. Between October 2012 and December 2014, consecutive CHB/CHC patients fulfilling the inclusion criteria were included-age more than 18 years, informed written consent, willing and suitable for liver biopsy...
June 22, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28640694/assessment-of-rectal-tumors-with-shear-wave-elastography-before-surgery-comparison-with-endorectal-us
#4
Li-Da Chen, Wei Wang, Jian-Bo Xu, Jian-Hui Chen, Xin-Hua Zhang, Hui Wu, Jin-Ning Ye, Jin-Ya Liu, Zhi-Qiang Nie, Ming-De Lu, Xiao-Yan Xie
Purpose To compare the value of endorectal ultrasonography (US) with shear-wave elastography (SWE) in staging rectal tumors before surgery. Materials and Methods This prospective study was approved by the institutional review board and written informed consent was obtained. In a pilot cohort from April 2015 to January 2016, 70 patients with rectal adenocarcinomas and/or adenomas confirmed with histopathologic examination underwent both endorectal US and SWE. Tumor stiffness and three regions of reference backgrounds, as well as tumor stiffness ratios (SRs) versus these backgrounds, were analyzed...
June 21, 2017: Radiology
https://www.readbyqxmd.com/read/28634626/hepatic-shear-wave-elastography-in-children-under-free-breathing-and-breath-hold-conditions
#5
Caroline Jung, Michael Groth, Kay Uwe Petersen, Anna Hammel, Florian Brinkert, Enke Grabhorn, Sören Alexander Weidemann, Jasmin Busch, Gerhard Adam, Jochen Herrmann
OBJECTIVES: To compare hepatic 2D shear wave elastography (2D SWE) in children between free-breathing and breath-hold conditions, in terms of measurement agreement and time expenditure. METHODS: A cohort of 57 children (12.7±4.3 years) who underwent standardized 2D SWE between May and October 2015 were retrospectively evaluated. Liver elastograms were obtained under free-breathing and breath-hold conditions and time expenditure was measured. Median stiffness, interquartile range (IQR), and IQR/median ratio were calculated based on 12, six, and three elastograms...
June 20, 2017: European Radiology
https://www.readbyqxmd.com/read/28634041/a-machine-learning-algorithm-toward-color-analysis-for-chronic-liver-disease-classification-employing-ultrasound-shear-wave-elastography
#6
Ilias Gatos, Stavros Tsantis, Stavros Spiliopoulos, Dimitris Karnabatidis, Ioannis Theotokas, Pavlos Zoumpoulis, Thanasis Loupas, John D Hazle, George C Kagadis
The purpose of the present study was to employ a computer-aided diagnosis system that classifies chronic liver disease (CLD) using ultrasound shear wave elastography (SWE) imaging, with a stiffness value-clustering and machine-learning algorithm. A clinical data set of 126 patients (56 healthy controls, 70 with CLD) was analyzed. First, an RGB-to-stiffness inverse mapping technique was employed. A five-cluster segmentation was then performed associating corresponding different-color regions with certain stiffness value ranges acquired from the SWE manufacturer-provided color bar...
June 17, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28624924/evaluation-of-hepatic-fibrosis-a-review-from-the-society-of-abdominal-radiology-disease-focus-panel
#7
REVIEW
Jeanne M Horowitz, Sudhakar K Venkatesh, Richard L Ehman, Kartik Jhaveri, Patrick Kamath, Michael A Ohliger, Anthony E Samir, Alvin C Silva, Bachir Taouli, Michael S Torbenson, Michael L Wells, Benjamin Yeh, Frank H Miller
Hepatic fibrosis is potentially reversible; however early diagnosis is necessary for treatment in order to halt progression to cirrhosis and development of complications including portal hypertension and hepatocellular carcinoma. Morphologic signs of cirrhosis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) alone are unreliable and are seen with more advanced disease. Newer imaging techniques to diagnose liver fibrosis are reliable and accurate, and include magnetic resonance elastography and US elastography (one-dimensional transient elastography and point shear wave elastography or acoustic radiation force impulse imaging)...
June 17, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28622540/scattering-of-airy-elastic-sheets-by-a-cylindrical-cavity-in-a-solid
#8
F G Mitri
The prediction of the elastic scattering by voids (and cracks) in materials is an important process in structural health monitoring, phononic crystals, metamaterials and non-destructive evaluation/imaging to name a few examples. Earlier analytical theories and numerical computations considered the elastic scattering by voids in plane waves of infinite extent. However, current research suggesting the use of (limited-diffracting, accelerating and self-healing) Airy acoustical-sheet beams for non-destructive evaluation or imaging applications in elastic solids requires the development of an improved analytical formalism to predict the scattering efficiency used as a priori information in quantitative material characterization...
June 8, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28618813/ultrasonic-attenuation-of-polycrystalline-materials-with-a-distribution-of-grain-sizes
#9
Andrea P Arguelles, Joseph A Turner
Elastic wave scattering at grain boundaries in polycrystalline media can be quantified to determine microstructural properties. The amplitude drop observed for coherent wave propagation (attenuation) as well as diffuse-field scattering events have been extensively studied. In all cases, the scattering shows a clear dependence on grain size, grain shape, and microstructural texture. Models used to quantify scattering experiments are often developed assuming dependence on a single spatial length scale, usually, mean grain diameter...
June 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28618808/semi-analytical-modeling-of-ground-plate-interaction-for-general-elastic-boundary-conditions
#10
Loïc Grau, Bernard Laulagnet
This letter introduces ground/plate interaction using the concept of ground cross-modal impedance in the case of general elastic boundary conditions. Navier equations are generally used to account for ground vibration with two propagating waves, the dilatational wave and the shear wave. The plate equation of motion follows the Kirchhoff-Love hypothesis, where shear and rotational inertia are neglected in the plate thickness. The general elastic boundary conditions are expressed analytically through a two-dimensional Fourier series in the plate displacement solution...
June 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28618555/viscosity-of-a-classical-gas-the-rare-collision-versus-the-frequent-collision-regime
#11
A G Magner, M I Gorenstein, U V Grygoriev
The shear viscosity η for a dilute classical gas of hard-sphere particles is calculated by solving the Boltzmann kinetic equation in terms of the weakly absorbed plane waves. For the rare-collision regime, the viscosity η as a function of the equilibrium gas parameters-temperature T, particle number density n, particle mass m, and hard-core particle diameter d-is quite different from that of the frequent-collision regime, e.g., from the well-known result of Chapman and Enskog. An important property of the rare-collision regime is the dependence of η on the external ("nonequilibrium") parameter ω, frequency of the sound plane wave, that is absent in the frequent-collision regime at leading order of the corresponding perturbation expansion...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28617883/ruling-in-and-ruling-out-significant-fibrosis-and-cirrhosis-in-patients-with-chronic-hepatitis-c-using-a-shear-wave-measurement-method
#12
Giovanna Ferraioli, Laura Maiocchi, Raffaella Lissandrin, Carmine Tinelli, Annalisa De Silvestri, Carlo Filice
AIMS: To prospectively assess the cutoff values of a point shear wave measurement (SWM) method for ruling-in and ruling-out significant fibrosis and cirrhosis using transient elastography (TE) as the reference standard. METHOD: Consecutive patients with chronic hepatitis C were enrolled. Liver stiffness was assessed with the SWM method implemented on the HI VISION Ascendus ultrasound system (Hitachi Ltd, Japan) and with the TE method of the FibroScan® device (Echosens, France)...
June 2017: Journal of Gastrointestinal and Liver Diseases: JGLD
https://www.readbyqxmd.com/read/28617509/controlled-rotation-and-translation-of-spherical-particles-or-living-cells-by-surface-acoustic-waves
#13
Ianis Bernard, Alexander A Doinikov, Philippe Marmottant, David Rabaud, Cédric Poulain, Pierre Thibault
We show experimental evidence of the acoustically-assisted micromanipulation of small objects like solid particles or blood cells, combining rotation and translation, using high frequency surface acoustic waves. This was obtained from the leakage in a microfluidic channel of two standing waves arranged perpendicularly in a LiNbO3 piezoelectric substrate working at 36.3 MHz. By controlling the phase lag between the emitters, we could, in addition to translation, generate a swirling motion of the emitting surface which, in turn, led to the rapid rotation of spherical polystyrene Janus beads suspended in the channel and of human red and white blood cells up to several rounds per second...
June 15, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28617353/torsional-ultrasound-sensor-optimization-for-soft-tissue-characterization
#14
Juan Melchor, Rafael Muñoz, Guillermo Rus
Torsion mechanical waves have the capability to characterize shear stiffness moduli of soft tissue. Under this hypothesis, a computational methodology is proposed to design and optimize a piezoelectrics-based transmitter and receiver to generate and measure the response of torsional ultrasonic waves. The procedure employed is divided into two steps: (i) a finite element method (FEM) is developed to obtain a transmitted and received waveform as well as a resonance frequency of a previous geometry validated with a semi-analytical simplified model and (ii) a probabilistic optimality criteria of the design based on inverse problem from the estimation of robust probability of detection (RPOD) to maximize the detection of the pathology defined in terms of changes of shear stiffness...
June 15, 2017: Sensors
https://www.readbyqxmd.com/read/28614362/effect-of-pathological-heterogeneity-on-shear-wave-elasticity-imaging-in-the-staging-of-deep-venous-thrombosis
#15
Xiaona Liu, Na Li, Chaoyang Wen
BACKGROUND: We aimed to observe the relationship between the pathological components of a deep venous thrombus (DVT), which was divided into three parts, and the findings on quantitative ultrasonic shear wave elastography (SWE) to increase the accuracy of thrombus staging in a rabbit model. METHODS: A flow stenosis-induced vein thrombosis model was used, and the thrombus was divided into three parts (head, body and tail), which were associated with corresponding observation points...
2017: PloS One
https://www.readbyqxmd.com/read/28611483/longitudinal-shear-wave-imaging-for-elasticity-mapping-using-optical-coherence-elastography
#16
Jiang Zhu, Yusi Miao, Li Qi, Yueqiao Qu, Youmin He, Qiang Yang, Zhongping Chen
Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Previous transverse shear wave measurements could detect the shear modulus in the lateral region of the force; however, they could not provide the elastic information in the axial region of the force. In this study, we report the imaging and quantification of longitudinal shear wave propagation using optical coherence tomography to measure the elastic properties along the force direction...
May 15, 2017: Applied Physics Letters
https://www.readbyqxmd.com/read/28610712/the-effect-of-heating-rate-and-sintering-temperature-on-the-elastic-modulus-of-porcelain-tiles
#17
Elif Eren Gültekin
The scope of the present study is to investigate the change of elastic modulus with the physical and mechanical properties of porcelain tiles. In the study, porcelain tiles were sintered at different temperatures and at different heating rates to obtain minimum water absorption (%). After this, the time of flight of longitudinal and shear ultrasonic waves was measured through the tile. The time of flight of ultrasonic waves was measured using contact ultrasonic transducers operating on a pulse-echo mode. Using the time of flight of the ultrasonic waves and the thickness of the tiles, the velocity of the waves was determined...
June 3, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28609299/arterial-waveguide-model-for-shear-wave-elastography-implementation-and-in-vitro-validation
#18
Ali Vaziri Astaneh, Matthew W Urban, Wilkins Aquino, James F Greenleaf, Murthy N Guddati
Arterial stiffness is found to be an early indicator of many cardiovascular diseases. Among various techniques, shear wave elastography has emerged as a promising tool for estimating local arterial stiffness through the observed dispersion of guided waves. In this paper, we develop efficient models for the computational simulation of guided wave dispersion in arterial walls. The models are capable of considering fluid-loaded tubes, immersed in fluid or embedded in a solid, which are encountered in in vitro/ex vivo, and in vivo experiments...
July 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28607322/assessment-of-the-mechanical-properties-of-the-muscle-tendon-unit-by-supersonic-shear-wave-imaging-elastography-a-review
#19
Kelly Mônica Marinho E Lima, José Francisco Silva Costa Júnior, Wagner Coelho de Albuquerque Pereira, Liliam Fernandes de Oliveira
This review aimed to describe the state of the art in muscle-tendon unit (MTU) assessment by supersonic shear wave imaging (SSI) elastography in states of muscle contraction and stretching, during aging, and in response to injury and therapeutic interventions. A consensus exists that MTU elasticity increases during passive stretching or contraction, and decreases after static stretching, electrostimulation, massage, and dry needling. There is currently no agreement regarding changes in the MTU due to aging and injury...
April 15, 2017: Ultrasonography
https://www.readbyqxmd.com/read/28604279/diffusion-and-intravoxel-incoherent-motion-mr-imaging-based-virtual-elastography-a-hypothesis-generating-study-in-the-liver
#20
Denis Le Bihan, Shintaro Ichikawa, Utaroh Motosugi
Purpose To investigate the potential of diffusion magnetic resonance (MR) imaging to provide quantitative estimates of tissue stiffness without using mechanical vibrations in patients with chronic liver diseases and to generate a new elasticity-driven intravoxel incoherent motion (IVIM) contrast. Materials and Methods This retrospective study, conducted from January to April 2016, was approved by an institutional review board that waived the requirement for informed consent. Fifteen subjects were included (13 men and two women; mean age ± standard deviation, 73 years ± 8)...
June 12, 2017: Radiology
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