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Ultrasonic Imaging

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https://www.readbyqxmd.com/read/29923458/a-novel-microflow-phantom-dedicated-to-ultrasound-microvascular-measurements
#1
Virginie Grand-Perret, Jean-René Jacquet, Ingrid Leguerney, Baya Benatsou, Jean-Marc Grégoire, Georges Willoquet, Ayache Bouakaz, Nathalie Lassau, Stephanie Pitre-Champagnat
Tumor microvascularization is a biomarker of response to antiangiogenic treatments and is accurately assessed by ultrasound imaging. Imaging modes used to visualize slow flows include Power Doppler imaging, dynamic contrast-enhanced ultrasonography, and more recently, microvascular Doppler. Flow phantoms are used to evaluate the performance of Doppler imaging techniques, but they do not have a steady flow and sufficiently small channels. We report a novel device for robust and stable microflow measurements and the study of the microvascularization...
June 1, 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29857786/ultrasonic-nakagami-imaging-of-high-intensity-focused-ultrasound-induced-thermal-lesions-in-porcine-livers-ex-vivo-study
#2
Sheng-Min Huang, Hao-Li Liu, Dai-Wei Li, Meng-Lin Li
High-intensity focused ultrasound (HIFU) has demonstrated the capacity to be used for local thermal ablation in clinical surgery; however, relying solely on conventional ultrasound B-mode imaging to monitor HIFU thermal ablation and determine ablation levels remains a challenge. Here, we experimentally demonstrate the ability to use Nakagami imaging to monitor HIFU-induced thermal lesions in porcine livers ex vivo. Ultrasonic Nakagami imaging has been proven to be able to characterize tissues with different scatterer concentrations and distributions...
June 1, 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29848216/method-for-recovering-lost-ultrasonic-information-using-the-echo-intensity-mean
#3
Sara Bahramian, Craig K Abbey, Michael F Insana
The axial resolution of a B-mode (or intensity) image is limited by the bandwidth of the pulse envelope. In this report, we investigate the source of this limitation by examining the transfer of high-resolution information from the tissue impedance variance throughout the imaging process. For that purpose, we express the mean and variance of the echo-intensity signal as a linear system to track the flow of object information along the image-formation chain. The results reveal how demodulation influences the available information by discarding high spatial-frequency information...
May 1, 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29848202/is-kidney-stiffness-measured-using-elastography-influenced-mainly-by-vascular-factors-in-patients-with-diabetic-kidney-disease
#4
Flaviu Bob, Iulia Grosu, Ioan Sporea, Romulus Timar, Daniel Lighezan, Alina Popescu, Roxana Sirli, Roxana Buzas, Ligia Petrica, Mircea Munteanu, Adalbert Schiller
Studies published so far using ultrasound-based elastography in the kidneys, lack to prove a clear relationship between kidney shear wave speed (KSWS) and renal disease progression. Taking into account that the kidney is a highly vascularized organ, the present study aims to find a relationship between KSWS and vascular factors (blood pressure [BP], arterial stiffness). Our study included 38 diabetic kidney disease patients (mean age 56.52 ± 16.12 years, 19 female, 19 male). KSWS, an indicator of renal stiffness, was measured using point Shear Wave Elastography (pSWE; Siemens Acuson S2000)...
May 1, 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29862931/automated-identification-and-localization-of-the-inferior-vena-cava-using-ultrasound-an-animal-study
#5
Jiangang Chen, Jiawei Li, Xin Ding, Cai Chang, Xiaoting Wang, Dean Ta
Ultrasound measurement of the inferior vena cava (IVC) is widely implemented in the clinic. However, the process is time consuming and labor intensive, because the IVC diameter is continuously changing with respiration. In addition, artificial errors and intra-operator variations are always considerable, making the measurement inconsistent. Research efforts were recently devoted to developing semiautomated methods. But most required an initial identification of the IVC manually. As a first step toward fully automated IVC measurement, in this paper, we present an intelligent technique for automated IVC identification and localization...
July 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29862930/uitc-abstracts-2018
#6
(no author information available yet)
No abstract text is available yet for this article.
July 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29739309/performance-evaluation-of-adaptive-imaging-based-on-multiphase-apodization-with-cross-correlation-a-pilot-study-in-abdominal-ultrasound
#7
Junseob Shin, Yu Chen, Harshawn Malhi, Frank Chen, Jesse Yen
Degradation of image contrast caused by phase aberration, off-axis clutter, and reverberation clutter remains one of the most important problems in abdominal ultrasound imaging. Multiphase apodization with cross-correlation (MPAX) is a novel beamforming technique that enhances ultrasound image contrast by adaptively suppressing unwanted acoustic clutter. MPAX employs multiple pairs of complementary sinusoidal phase apodizations to intentionally introduce grating lobes that can be used to derive a weighting matrix, which mostly preserves the on-axis signals from tissue but reduces acoustic clutter contributions when multiplied with the beamformed radio-frequency (RF) signals...
July 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29683052/effect-of-transmit-beamforming-on-clutter-levels-in-transthoracic-echocardiography
#8
Vaibhav Kakkad, Melissa LeFevre, Kingshuk Roy Choudhury, Joseph Kisslo, Gregg E Trahey
Transmit beamforming has a strong impact on several factors that govern image quality, field-of-view, and frame-rate in ultrasound imaging. For cardiac applications, the visualization of fine structures and the ability to track their motion is equally important. Consequently, beamforming choices for echocardiography aim to optimize these trade-offs. Acoustic clutter can dramatically impact image quality and degrade the diagnostic value of cardiac ultrasound imaging. Clutter levels, however, are closely tied to the choice of beamforming configuration...
July 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29506441/three-dimensional-visualization-of-ultrasound-backscatter-statistics-by-window-modulated-compounding-nakagami-imaging
#9
Zhuhuang Zhou, Shuicai Wu, Man-Yen Lin, Jui Fang, Hao-Li Liu, Po-Hsiang Tsui
In this study, the window-modulated compounding (WMC) technique was integrated into three-dimensional (3D) ultrasound Nakagami imaging for improving the spatial visualization of backscatter statistics. A 3D WMC Nakagami image was produced by summing and averaging a number of 3D Nakagami images (number of frames denoted as N) formed using sliding cubes with varying side lengths ranging from 1 to N times the transducer pulse. To evaluate the performance of the proposed 3D WMC Nakagami imaging method, agar phantoms with scatterer concentrations ranging from 2 to 64 scatterers/mm3 were made, and six stages of fatty liver (zero, one, two, four, six, and eight weeks) were induced in rats by methionine-choline-deficient diets (three rats for each stage, total n = 18)...
May 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29353529/ultrasound-shear-wave-elastography-of-the-normal-prostate-interobserver-reproducibility-and-comparison-with-functional-magnetic-resonance-tissue-characteristics
#10
Hugh Harvey, Veronica Morgan, Jeremie Fromageau, Tuathan O'Shea, Jeffrey Bamber, Nandita M deSouza
The purpose of this study was to establish interobserver reproducibility of Young's modulus (YM) derived from ultrasound shear wave elastography (US-SWE) in the normal prostate and correlate it with multiparametric magnetic resonance imaging (mpMRI) tissue characteristics. Twenty men being screened for prostate cancer underwent same-day US-SWE (10 done by two blinded, newly-trained observers) and mpMRI followed by 12-core biopsy. Bland-Altman plots established limits of agreement for YM. Quantitative data from the peripheral zone (PZ) and the transitional zone (TZ) for YM, apparent diffusion coefficient (ADC, mm2 /s from diffusion-weighted MRI), and Ktrans (volume transfer coefficient, min-1 ), Ve (extravascular-extracellular space, %), Kep (rate constant, /min), and initial area under the gadolinium concentration curve (IAUGC60, mmol/L/s) from dynamic contrast-enhanced MRI were obtained for slice-matched prostate sextants...
May 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29332489/thermoacoustic-lensing-in-ultrasound-imaging-of-nonechogenic-tissue-during-high-intensity-focused-ultrasound-exposure
#11
Matthew Jahns, Dan MacDougall, Robert B A Adamson
We develop a ray-tracing theory to describe the effects of thermoacoustic lensing during high-intensity focused ultrasound (HIFU) on ultrasound images of reflectors lying distal to the HIFU focal region and discuss the application of thermal lensing effects to dose monitoring in HIFU therapy. By analyzing the effects of thermal and geometric delays of acoustic rays passing through a region of tissue undergoing localized heating, we show how the shape of a reflector distal to the heated region can be predicted and present experimental measurements in good agreement with the model...
May 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29207924/speckle-tracking-in-transcranial-ultrasound-allows-noninvasive-analysis-of-pulsation-patterns-of-the-third-ventricle
#12
Benjamin Würzer, Cristina Laza, Jörn Pons-Kühnemann, Manfred Kaps, Bernd Junge, Florian C Roessler
Cerebrospinal fluid (CSF) flow is sensitive to many cerebral disorders. We aimed to develop a noninvasive bedside method to detect physiological and pathological CSF phenomena by measuring pulsation patterns of the third ventricle. By transcranial B-mode ultrasound, electrocardiography (ECG)-gated video loops of the third ventricle were acquired. "Speckle tracking" software was used to quantify the relative change of its width. We conducted measurements of nine cardiac cycles in 11 healthy subjects in sitting and in supine position during Valsalva maneuver to investigate the influence of an increased intracranial pressure on the relative deformation of the third ventricle...
March 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29182056/lesion-segmentation-in-automated-3d-breast-ultrasound-volumetric-analysis
#13
Richa Agarwal, Oliver Diaz, Xavier Lladó, Albert Gubern-Mérida, Joan C Vilanova, Robert Martí
Mammography is the gold standard screening technique in breast cancer, but it has some limitations for women with dense breasts. In such cases, sonography is usually recommended as an additional imaging technique. A traditional sonogram produces a two-dimensional (2D) visualization of the breast and is highly operator dependent. Automated breast ultrasound (ABUS) has also been proposed to produce a full 3D scan of the breast automatically with reduced operator dependency, facilitating double reading and comparison with past exams...
March 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/29182054/a-quantitative-method-for-the-evaluation-of-spatial-resolution-in-quality-control-of-b-mode-ultrasound-images
#14
Sabina Strocchi, Francesco Larghi, Raffaele Novario
The work describes a method to quantitatively evaluate spatial resolution in B-mode quality control images as radial modulation transfer function (MTF). The method is easy to use in in-field quality assurance programs in clinical institutions, as it is fast and can be performed with the help of phantoms that are already used for routine quality control. It uses a round insert with different echogenic characteristics compared with the phantom background. The method was automated with a MATLAB® routine, which can be run in full automatic mode or with a grade of interaction by the user, as is sometimes necessary with low-quality images...
March 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28945169/analysis-of-two-quantitative-ultrasound-approaches
#15
Pauline Muleki-Seya, Aiguo Han, Michael P Andre, John W Erdman, William D O'Brien
There are two well-known ultrasonic approaches to extract sets of quantitative parameters: Lizzi-Feleppa (LF) parameters: slope, intercept, and midband; and quantitative ultrasound (QUS)-derived parameters: effective scatterer diameter (ESD) and effective acoustic concentration (EAC). In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD ([Formula: see text]), and from experimental data, LF midband is correlated to EAC ([Formula: see text])...
March 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28832256/3d-tendon-strain-estimation-using-high-frequency-volumetric-ultrasound-images-a-feasibility-study
#16
Catarina Carvalho, Pieter Slagmolen, Stijn Bogaerts, Lennart Scheys, Jan D'hooge, Koen Peers, Frederik Maes, Paul Suetens
Estimation of strain in tendons for tendinopathy assessment is a hot topic within the sports medicine community. It is believed that, if accurately estimated, existing treatment and rehabilitation protocols can be improved and presymptomatic abnormalities can be detected earlier. State-of-the-art studies present inaccurate and highly variable strain estimates, leaving this problem without solution. Out-of-plane motion, present when acquiring two-dimensional (2D) ultrasound (US) images, is a known problem and may be responsible for such errors...
March 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28720056/influence-of-tissue-microstructure-on-shear-wave-speed-measurements-in-plane-shear-wave-elastography-a-computational-study-in-lossless-fibrotic-liver-media
#17
Yu Wang, Jingfeng Jiang
Shear wave elastography (SWE) has been used to measure viscoelastic properties for characterization of fibrotic livers. In this technique, external mechanical vibrations or acoustic radiation forces are first transmitted to the tissue being imaged to induce shear waves. Ultrasonically measured displacement/velocity is then utilized to obtain elastographic measurements related to shear wave propagation. Using an open-source wave simulator, k-Wave, we conducted a case study of the relationship between plane shear wave measurements and the microstructure of fibrotic liver tissues...
January 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28703685/a-method-for-gray-scale-imaging-of-blood-flow-using-high-frequency-ultrasound
#18
Jun Yang, Chao Pang, Xue-Dong Song, Xuan Gao
This paper presents a new method that complements current techniques available in the high-frequency blood imaging field. A comprehensive scattering model was established to determine the feasibility and frequency range of the blood flow imaging of superficial organs and tissues using high-frequency ultrasound. The transmitting and receiving modes and an algorithm were designed to obtain blood flow information based on differentiation between tissues and blood flow. The system was created and tested first with a model that simulates blood flow and was then used on human tissue...
January 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28703644/effects-of-phase-aberration-and-phase-aberration-correction-on-the-minimum-variance-beamformer
#19
Gustavo Chau, Jeremy Dahl, Roberto Lavarello
The minimum variance (MV) beamformer has the potential to enhance the resolution and contrast of ultrasound images but is sensitive to steering vector errors. Robust MV beamformers have been proposed but mainly evaluated in the presence of gross sound speed mismatches, and the impact of phase aberration correction (PAC) methods in mitigating the effects of phase aberration in MV beamformed images has not been explored. In this study, an analysis of the effects of aberration on conventional MV and eigenspace MV (ESMV) beamformers is carried out...
January 2018: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28691586/low-cost-volumetric-ultrasound-by-augmentation-of-2d-systems-design-and-prototype
#20
Carl D Herickhoff, Matthew R Morgan, Joshua S Broder, Jeremy J Dahl
Conventional two-dimensional (2D) ultrasound imaging is a powerful diagnostic tool in the hands of an experienced user, yet 2D ultrasound remains clinically underutilized and inherently incomplete, with output being very operator dependent. Volumetric ultrasound systems can more fully capture a three-dimensional (3D) region of interest, but current 3D systems require specialized transducers, are prohibitively expensive for many clinical departments, and do not register image orientation with respect to the patient; these systems are designed to provide improved workflow rather than operator independence...
January 2018: Ultrasonic Imaging
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