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IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

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https://www.readbyqxmd.com/read/27913343/a-frequency-shift-method-to-measure-shear-wave-attenuation-in-soft-tissues
#1
Simon Bernard, Siavash Kazemirad, Guy Cloutier
In vivo quantification of shear wave attenuation in soft tissues may help to better understand human tissue rheology and lead to new diagnostic strategies. Attenuation is difficult to measure in acoustic radiation force elastography because the shear wave amplitude decreases due to a combination of diffraction and viscous attenuation. Diffraction correction requires assuming a cylindrical wavefront and an isotropic propagation medium, which may not be the case in some applications. In this study, the frequency shift method, used in ultrasound imaging and seismology, was adapted for shear wave attenuation measurement in elastography...
December 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913342/efficient-strategies-for-estimating-the-spatial-coherence-of-backscatter
#2
Dongwoon Hyun, Anna Lisa C Crowley, Jeremy J Dahl
The spatial coherence of ultrasound backscatter has been proposed to reduce clutter in medical imaging, to measure the anisotropy of the scattering source, and to improve the detection of blood flow. These techniques rely on correlation estimates that are obtained using computationally expensive strategies. In this study, we assess existing spatial coherence estimation methods and propose three computationally efficient modifications: a reduced kernel, a downsampled receive aperture, and the use of an ensemble correlation coefficient...
December 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913341/quantification-of-shear-wave-scattering-from-far-surface-defects-via-ultrasonic-wavefield-measurements
#3
Alexander J Dawson, Jennifer E Michaels, Joseph W Kummer, Thomas E Michaels
Nondestructive evaluation methods rely on prior knowledge of the expected interaction of ultrasonic waves with defects to inform detection and characterization decisions. Wavefield imaging, which refers to the measurement of signals originating from a spatially fixed source on a two-dimensional rectilinear grid, can be applied to visualize the effect of a subsurface scatterer on surface-measured wave motion. Here, obliquely-incident shear waves are directed at the far surface of a plate containing a through-hole using the well-known angle-beam ultrasonic inspection method...
December 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913340/efficient-3d-reconstruction-in-ultrasound-elastography-via-a-sparse-iteration-based-on-markov-random-fields
#4
Atul Ingle, Tomy Varghese, William Sethares
Percutaneous needle-based liver ablation procedures are becoming increasingly common for treatment of small isolated tumors in hepatocellular carcinoma patients who are not candidates for surgery. Rapid three dimensional visualization of liver ablations has potential clinical value because it can enable interventional radiologists to plan and execute needle-based ablation procedures with real time feedback. Ensuring the right volume of tissue is ablated is desirable to avoid recurrence of tumors from residual untreated cancerous cells...
November 29, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913339/a-parametric-study-for-the-design-of-an-optimized-ultrasonic-percussive-planetary-drill-tool
#5
Xuan Li, Patrick Harkness, Kevin Worrall, Ryan Timoney, Margaret Lucas
Traditional rotary drilling for planetary rock sampling, in-situ analysis and sample return, is challenging because the axial force and holding torque requirements are not necessarily compatible with lightweight spacecraft architectures in low-gravity environments. This article seeks to optimize an ultrasonic-percussive drill tool to achieve rock penetration with lower reacted force requirements, with a strategic view towards building an Ultrasonic Planetary Core Drill (UPCD) device. The UPCD is a descendant of the Ultrasonic/Sonic Driller/Corer (USDC) technique...
November 29, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913338/intracardiac-vortex-dynamics-by-high-frame-rate-doppler-vortography-i-in-vivo-i-comparison-with-vector-flow-mapping-and-4-d-flow-mri
#6
Julia Faurie, Mathilde Baudet, Kondo Claude Assi, Dominique Auger, Guillaume Gilbert, Francois Tournoux, Damien Garcia
Recent studies have suggested that intracardiac vortex flow imaging could be of clinical interest to early diagnose the diastolic heart function. Doppler vortography has been intro-duced as a simple color Doppler method to detect and quantify intraventricular vortices. This method is able to locate a vortex core based on the recognition of an antisymmetric pattern in the Doppler velocity field. Because the heart is a fast-moving organ, high frame rates are needed to decipher the whole blood vortex dynamics during diastole...
November 29, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27898380/famus-ii-a-fast-and-mechanistic-ultrasound-simulator-using-an-impulse-response-approach
#7
Luis Aguilar, Justin Wong, David A Steinman, Richard S C Cobbold
Real-time simulation of ultrasound images is increasingly important for providing a means of presenting a wide variety of clinical images for the training of ultrasound specialists and technologists. In order to realistically represent the visual effects caused by changes to the transducer position or its focal properties, very rapid transducer field response calculations are needed, typically on the order of a fraction of a second. Currently available methods are severely limited in this regard. Based on the impulse response, a point source/receiver method for accurately calculating the fields produced by ultrasound transducer arrays is proposed and illustrated with realistic B-mode and Doppler spectral display simulations...
November 24, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27875220/high-quality-factor-low-temperature-dependency-smr-fbar-based-on-bst-using-mod-deposition-method
#8
Almonir Mansour, Thottam Kalkur
This paper presents the design, fabrication and experimental evaluation of switchable and tunable thin film bulk acoustic wave (BAW) resonators and filters with MOSD deposited BST for radio frequency (RF) applications. The switchability and tunability of these devices come from utilizing the electrostrictive effect of ferroelectric materials such as barium strontium titanate (BST) with the application of an external dc bias voltage. The BAW resonators and filters in this paper were fabricated on high resistivity silicon substrate as solidly mounted resonator (SMR) structure with eight layers of silicon dioxide and tantalum oxide as a Bragg reflector...
November 18, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27849526/an-adaptive-array-excitation-scheme-for-the-unidirectional-enhancement-of-guided-waves
#9
Chris Adams, Sevan Harput, David Cowell, Thomas Carpenter, David Charutz, Steven Freear
Control over the direction of wave propagation allows an engineer to spatially locate defects. When imaging with longitudinal waves, time delays can be applied to each element of a phased array transducer to steer a beam. Because of the highly dispersive nature of guided waves, this beamsteering approach is sub-optimal. More appropriate time delays can be chosen to direct a guided wave if the dispersion relation of the material is known. Existing techniques however need a priori knowledge of material thickness and acoustic velocity, which changes as a function of temperature and strain...
November 11, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27845660/investigating-shear-wave-physics-in-a-generic-left-ventricular-model-via-in-vitro-experiments-and-finite-element-simulations
#10
Annette Caenen, Mathieu Pernot, Darya Shcherbakova, Luc Mertens, Mathias Kersemans, Patrick Segers, Abigail Swillens
Shear wave elastography (SWE) is a potentially valuable tool to non-invasively assess ventricular function in children with cardiac disorders, which could help in the early detection of abnormalities in muscle characteristics. Initial experiments demonstrated the potential of this technique in measuring ventricular stiffness, however, its performance remains to be validated as complicated shear wave (SW) propagation characteristics are expected to arise due to the complex non-homogeneous structure of the myocardium...
November 9, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27845659/pipe-phantoms-with-applications-in-molecular-imaging-and-system-characterization
#11
Shiying Wang, Elizabeth B Herbst, Stephen D Pye, Carmel M Moran, John A Hossack
Pipe (vessel) phantoms mimicking human tissue and blood flow are widely used for cardiovascular related research in medical ultrasound. Pipe phantom studies require the development of materials and liquids that match the acoustic properties of soft tissue, blood vessel wall, and blood. Over recent years, pipe phantoms have been developed to mimic the molecular properties of the simulated blood vessels. In this paper, the design, construction, and functionalization of pipe phantoms are introduced and validated for applications in molecular imaging and ultrasound imaging system characterization...
November 9, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27845658/shear-wave-imaging-of-in-vivo-breast-tissue-by-color-doppler-shear-wave-elastography
#12
Yoshiki Yamakoshi, Takahito Nakajima, Toshihiro Kasahara, Mayuko Yamazaki, Ren Koda, Naoki Sunaguchi
Shear wave elastography is a distinctive method to access the viscoelastic characteristic of the soft tissue that is difficult to obtain by other imaging modalities. This paper proposes a novel shear wave elastography (color Doppler shear wave imaging: CD SWI) for breast tissue. Continuous shear wave is produced by a small lightweight actuator which is attached to the tissue surface. Shear wave wavefront which propagates in tissue is reconstructed as a binary pattern which consists of zero and the maximum flow velocities on color flow image (CFI)...
November 8, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27834645/robust-detection-of-fast-and-slow-frequency-jumps-of-atomic-clocks
#13
Lorenzo Galleani, Patrizia Tavella
This paper presents a frequency jump detector for atomic clocks. The detector considers both fast frequency jumps, which are abrupt variations of the clock frequency trend, and slow frequency jumps, which correspond to variations of the frequency trend over a finite time interval. These anomalies are particularly critical for space clocks in global navigation satellite systems (GNSS). The developed detector is robust in the sense that it can deal with time-varying frequency trends, sinusoidal terms, outliers and missing data...
November 4, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27831870/breast-ultrasound-technology-and-performance-evaluation-of-ultrasound-equipment-b-mode
#14
E Sassaroli, A Scorza, C Crake, S A Sciuto, M Park
Ultrasound (US) has become increasingly important in imaging and image-guided interventional procedures. In order to ensure that the imaging equipment performs to the highest level achievable and thus provides reliable clinical results a number of Quality Control (QC) methods have been developed. Such QC is increasingly required by accrediting agencies and professional organizations, however, these requirements typically do not include detailed procedures for how the tests should be performed. In this paper a detailed overview of QC methods for general and breast ultrasound imaging using computer-based objective methods is described...
November 2, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27810808/biasing-of-capacitive-micromachined-ultrasonic-transducers
#15
Giosue Caliano, Giulia Matrone, Alessandro Stuart Savoia
Capacitive Micromachined Ultrasonic Transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are micro-electromechanical (MEMS) devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies in its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and highperformance devices, including both one- or two-dimensional arrays...
October 28, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27810807/ultrasound-scattering-anisotropy-visualization-with-ultrasound-tomography
#16
Quinn Barber, Roger J Zemp
An ultrasound tomography system was used to image ultrasound scattering anisotropy in phantom experiments. This anisotropy was visualized as vector fields with arrows corresponding to the principal scattering angle of each pixel. Ultrasound tomography with a ring array system allows for a large range of transmit and receive angle combinations, producing real-time acquisition anisotropy maps unachievable with previous single-element and linear array studies. Resolution was measured to be 138±48μm , averaged over seven different placements within the transducer's field of view...
October 28, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27810806/evaluation-of-the-transverse-oscillation-technique-for-cardiac-phased-array-imaging-a-theoretical-study
#17
Brecht Heyde, Nick Bottenus, Jan D'hooge, Gregg E Trahey
The transverse oscillation (TO) technique can improve the estimation of tissue motion perpendicular to the ultrasound beam direction. TOs can be introduced using plane wave (PW) insonification and bi-lobed Gaussian apodisation (BA) on receive (abbreviated as PWTO). Furthermore, the TO frequency can be doubled after a heterodyning demodulation process is performed (abbreviated as PWTO*). This study is concerned with identifying the limitations of the PWTO technique in the specific context of myocardial deformation imaging with phased arrays and investigating the conditions in which it remains advantageous over traditional focused (FOC) beamforming...
October 28, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27810805/characterisation-of-contrast-agent-microbubbles-for-ultrasound-imaging-and-therapy-research
#18
Helen Mulvana, Richard J Browning, Ying Luan, Nico de Jong, Meng-Xing Tang, Robert J Eckersley, Eleanor Stride
The high efficiency with which gas microbubbles can scatter ultrasound compared to the surrounding blood pool or tissues has led to their widespread employment as contrast agents in ultrasound imaging. In recent years their applications have been extended to include super-resolution imaging and the stimulation of localized bio-effects for therapy. The growing exploitation of contrast agents in ultrasound, and in particular these recent developments, have amplified the need to characterize and fully understand microbubble behavior...
October 26, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27775904/design-of-hifu-transducers-for-generating-specified-nonlinear-ultrasound-fields
#19
Pavel B Rosnitskiy, P V Yuldashev, Oleg A Sapozhnikov, Adam Maxwell, Wayne Kreider, Michael R Bailey, Vera A Khokhlova
Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements for the pressure levels and degree of nonlinear waveform distortion at the focus. The goal of this work was to determine transducer design parameters that produce either a specified shock amplitude in the focal waveform or specified peak pressures while still maintaining quasilinear conditions at the focus. Multiparametric nonlinear modeling based on the KZK equation with an equivalent source boundary condition was employed...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27775903/contrast-enhanced-superharmonic-imaging-for-acoustic-angiography-using-reduced-form-factor-lateral-mode-transmitters-for-intravascular-and-intracavity-applications
#20
Zhuochen Wang, Karl Heath Martin, Wenbin Huang, Paul A Dayton, Xiaoning Jiang
Techniques to image the microvasculature may play an important role in imaging tumor-related angiogenesis and vasa vasorum associated with vulnerable atherosclerotic plaques. However, the microvasculature associated with these pathologies is difficult to detect using traditional B-mode ultrasound or even harmonic imaging due to small vessel size and poor differentiation from surrounding tissue. Acoustic angiography, a microvascular imaging technique which utilizes superharmonic imaging (detection of higher order harmonics of microbubble response), can yield a much higher contrast to tissue ratio (CTR) than second harmonic imaging methods...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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