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Ultrasound phantom

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https://www.readbyqxmd.com/read/27929509/comparison-of-the-low-contrast-detectability-of-two-ultrasound-systems-using-a-greyscale-phantom
#1
Robert Lorentsson, Nasser Hosseini, Jan-Olof Johansson, Wiebke Rosenberg, Benny Stenborg, Lars Gunnar Månsson, Magnus Båth
The purpose of the present study was to evaluate the relevance of using a phantom to simulate a clinical situation where small low contrast objects are embedded in relatively homogeneous organs in order to discriminate between different ultrasound machines, taking into account human observer variability. One high-end and one general ultrasound machine using the same probe were included. Images containing 4 and 6.4-mm objects of four different contrasts were collected from a greyscale phantom at different depths...
November 8, 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27925588/fabrication-of-two-flow-phantoms-for-doppler-ultrasound-imaging
#2
Xiaowei Zhou, David Kenwright, Shiying Wang, John Hossack, Peter Hoskins
Flow phantoms are widely used in studies associated with Doppler ultrasound measurements, acting as an effective experimental validation system in cardiovascular related research and in new algorithm / instrumentation development. The development of materials that match the acoustic and mechanical properties of vascular system are of great interest while designing flow phantoms. Although recipes that meet the flow phantom standard defined by International Electrotechnical Commission (IEC) 61685 are already available in the literature, standard procedure of material preparations and phantom fabrications have not been well established...
December 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27921121/a%C3%A2-4d-ultrasound-real-time-tracking-system-for-external-beam-radiotherapy-of-upper-abdominal-lesions-under-breath-hold
#3
Dwi Seno Kuncoro Sihono, Lena Vogel, Christel Weiß, Johannes Thölking, Frederik Wenz, Frank Lohr, Judit Boda-Heggemann, Hansjörg Wertz
BACKGROUND AND PURPOSE: To evaluate a novel four-dimensional (4D) ultrasound (US) tracking system for external beam radiotherapy of upper abdominal lesions under computer-controlled deep-inspiration breath-hold (DIBH). MATERIALS AND METHODS: The tracking accuracy of the research 4D US system was evaluated using two motion phantoms programmed with sinusoidal and breathing patterns to simulate free breathing and DIBH. Clinical performance was evaluated with five healthy volunteers...
December 5, 2016: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/27914403/acoustic-attenuation-imaging-of-tissue-bulk-properties-with-a-priori-information
#4
Fong Ming Hooi, Oliver Kripfgans, Paul L Carson
Attenuation of ultrasound waves traversing a medium is not only a result of absorption and scattering within a given tissue, but also of coherent scattering, including diffraction, refraction, and reflection of the acoustic wave at tissue boundaries. This leads to edge enhancement and other artifacts in most reconstruction algorithms, other than 3D wave migration with currently impractical, implementations. The presented approach accounts for energy loss at tissue boundaries by normalizing data based on variable sound speed, and potential density, of the medium using a k-space wave solver...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27913343/a-frequency-shift-method-to-measure-shear-wave-attenuation-in-soft-tissues
#5
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/27913340/efficient-3d-reconstruction-in-ultrasound-elastography-via-a-sparse-iteration-based-on-markov-random-fields
#6
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/27908486/an-inverse-method-to-determine-arterial-stiffness-with-guided-axial-waves
#7
Guo-Yang Li, Qiong He, Lin Jia, Ping He, Jianwen Luo, Yanping Cao
Many cardiovascular diseases can alter arterial stiffness; therefore, measurement of arterial wall stiffness can provide valuable information for both diagnosis of such diseases in the clinic and evaluation of the effectiveness of relevant drugs. However, quantitative assessment of the in vivo elastic properties of arterial walls in a non-invasive manner remains a great challenge. In this study, we found that the elastic modulus of the arterial wall can be extracted from the dispersion curve of the guided axial wave (GAW) measured using the ultrasound elastography method...
November 28, 2016: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/27908160/correspondence-optimization-in-2d-standardized-carotid-wall-thickness-map-by-description-length-minimization-a-tool-for-increasing-reproducibility-of-3d-ultrasound-based-measurements
#8
Yimin Chen, Bernard Chiu
PURPOSE: The previously described 2D standardized vessel-wall-plus-plaque thickness (VWT) maps constructed from 3D ultrasound vessel wall measurements using an arc-length (AL) scaling approach adjusted the geometric variability of carotid arteries and has allowed for the comparisons of VWT distributions in longitudinal and cross-sectional studies. However, this mapping technique did not optimize point correspondence of the carotid arteries investigated. The potential misalignment may lead to errors in point-wise VWT comparisons...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27903789/a-color-doppler-shear-wave-imaging-phase-reconstruction-method-using-four-color-flow-images
#9
Naoki Sunaguchi, Yoshiki Yamakoshi, Takahito Nakajima
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...
November 30, 2016: Ultrasonic Imaging
https://www.readbyqxmd.com/read/27896015/development-of-a-multi-wavelength-diffuse-optical-tomography-system-for-early-diagnosis-of-rheumatoid-arthritis-simulation-phantoms-and-healthy-human-studies
#10
Hao Yang Wu, Andrew Filer, Iain Styles, Hamid Dehghani
A multi-wavelength diffuse optical tomography (DOT) system has been developed to directly extract physiological information, such as total haemoglobin concentration, from tissue in human hand joints. Novel methods for 3D surface imaging and spectrally constrained image reconstruction are introduced and their potential application to imaging of rheumatoid arthritis is discussed. Results are presented from simulation studies as well as experiments using phantoms and data from imaging of three healthy volunteers...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27895986/combined-frequency-domain-photoacoustic-and-ultrasound-imaging-for-intravascular-applications
#11
Robin F Castelino, Michael Hynes, Chelsea E Munding, Sergey Telenkov, F Stuart Foster
Intravascular photoacoustic (IVPA) imaging has the potential to characterize lipid-rich structures based on the optical absorption contrast of tissues. In this study, we explore frequency domain photoacoustics (FDPA) for intravascular applications. The system employed an intensity-modulated continuous wave (CW) laser diode, delivering 1W over an intensity modulated chirp frequency of 4-12MHz. We demonstrated the feasibility of this approach on an agar vessel phantom with graphite and lipid targets, imaged using a planar acoustic transducer co-aligned with an optical fibre, allowing for the co-registration of IVUS and FDPA images...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27893440/a-3d-reconstruction-algorithm-for-magneto-acoustic-tomography-with-magnetic-induction-based-on-ultrasound-transducer-characteristics
#12
Ren Ma, Xiaoqing Zhou, Shunqi Zhang, Tao Yin, Zhipeng Liu
In this study we present a three-dimensional (3D) reconstruction algorithm for magneto-acoustic tomography with magnetic induction (MAT-MI) based on the characteristics of the ultrasound transducer. The algorithm is investigated to solve the blur problem of the MAT-MI acoustic source image, which is caused by the ultrasound transducer and the scanning geometry. First, we established a transducer model matrix using measured data from the real transducer. With reference to the S-L model used in the computed tomography algorithm, a 3D phantom model of electrical conductivity is set up...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27884775/tuning-acoustic-and-mechanical-properties-of-materials-for-ultrasound-phantoms-and-smart-substrates-for-cell-cultures
#13
A Cafarelli, A Verbeni, A Poliziani, P Dario, A Menciassi, L Ricotti
: Materials with tailored acoustic properties are of great interest for both the development of tissue-mimicking phantoms for ultrasound tests and smart scaffolds for ultrasound mediated tissue engineering and regenerative medicine. In this study, we assessed the acoustic properties (speed of sound, acoustic impedance and attenuation coefficient) of three different materials (agarose, polyacrylamide and polydimethylsiloxane) at different concentrations or cross-linking levels and doped with different concentrations of barium titanate ceramic nanoparticles...
November 21, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/27868241/high-intensity-focused-ultrasound-treatment-for-skin-ex-vivo-evaluation
#14
J-H Park, S-D Lim, S H Oh, J H Lee, U C Yeo
BACKGROUND/PURPOSE: High-intensity focused ultrasound (HIFU) has been used for skin tightening. However, there is a rising concern of irreversible adverse effects. Our aim was to evaluate the depth of thermal injury zone after HIFU energy passes through different condition. MATERIALS AND METHODS: To analyze the consistency of the HIFU device, phantom tests were performed. Simulations were performed on ex vivo porcine tissues to estimate the area of the thermal coagulation point (TCP) according to the applied energy and skin condition...
November 20, 2016: Skin Research and Technology
https://www.readbyqxmd.com/read/27861273/thermodilution-determined-internal-jugular-venous-flow
#15
Peter Rasmussen, Mario Widmer, Matthias P Hilty, Mike Hug, Henrik Sørensen, Shigehiko Ogoh, Kohei Sato, Niels H Secher, Marco Maggiorini, Carsten Lundby
PURPOSE: Cerebral blood flow (CBF) increases ~20% during whole body exercise although a Kety-Schmidt-determined CBF is reported to remain stable; a discrepancy that could reflect evaluation of arterial vs. internal jugular venous (IJV) flow and/or that CBF is influenced by posture. Here we test the hypothesis that IJV flow, as determined by retrograde thermodilution increases during exercise when body position is maintained. METHODS: Introducing retrograde thermodilution, IJV flow was measured in 8 healthy humans at supine and upright rest and during exercise in normoxia and hypoxia with results compared to changes in ultrasound-derived IJV flow and middle cerebral artery mean velocity (MCA Vmean)...
November 17, 2016: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/27847534/quality-assurance-testing-of-transoesophageal-echocardiography-probes
#16
Christopher McLeod, Kirsty McNeill, Karne McBride, Scott Inglis, Stephen D Pye
INTRODUCTION: In response to an ultrasound imaging issue with transoesophageal echocardiography probes, a testing protocol was developed to check features pertinent to the operation of these probes. The imaging problem was detected in multiple probes of the same make and model. METHODS: Over a two-year period, a series of 26 probes of this model were tested at acceptance, then three to six months later before being replaced due to a defect. A range of visual, mechanical and electrical tests were performed...
November 2016: Ultrasound: Journal of the British Medical Ultrasound Society
https://www.readbyqxmd.com/read/27845751/effects-of-non-elevation-focalized-linear-array-transducer-on-ultrasound-plane-wave-imaging
#17
Congzhi Wang, Yang Xiao, Jingjing Xia, Weibao Qiu, Hairong Zheng
Plane-wave ultrasound imaging (PWUS) has become an important method of ultrasound imaging in recent years as its frame rate has exceeded 10,000 frames per second, allowing ultrasound to be used for two-dimensional shear wave detection and functional brain imaging. However, compared to the traditional focusing and scanning method, PWUS images always suffer from a degradation of lateral resolution and contrast. To improve the image quality of PWUS, many different beamforming algorithms have been proposed and verified...
November 12, 2016: Sensors
https://www.readbyqxmd.com/read/27845659/pipe-phantoms-with-applications-in-molecular-imaging-and-system-characterization
#18
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
#19
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/27837312/a-combination-of-parabolic-and-grid-slope-interpolation-for-2d-tissue-displacement-estimations
#20
John Albinsson, Åsa Rydén Ahlgren, Tomas Jansson, Magnus Cinthio
Parabolic sub-sample interpolation for 2D block-matching motion estimation is computationally efficient. However, it is well known that the parabolic interpolation gives a biased motion estimate for displacements greater than |y.2| samples (y = 0, 1, …). Grid slope sub-sample interpolation is less biased, but it shows large variability for displacements close to y.0. We therefore propose to combine these sub-sample methods into one method (GS15PI) using a threshold to determine when to use which method...
November 11, 2016: Medical & Biological Engineering & Computing
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