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Ultrasound in Medicine & Biology

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https://www.readbyqxmd.com/read/28733030/accounting-for-the-spatial-observation-window-in-the-2-d-fourier-transform-analysis-of-shear-wave-attenuation
#1
Ned C Rouze, Yufeng Deng, Mark L Palmeri, Kathryn R Nightingale
Recent measurements of shear wave propagation in viscoelastic materials have been analyzed by constructing the 2-D Fourier transform (2DFT) of the shear wave signal and measuring the phase velocity c(ω) and attenuation α(ω) from the peak location and full width at half-maximum (FWHM) of the 2DFT signal at discrete frequencies. However, when the shear wave is observed over a finite spatial range, the 2DFT signal is a convolution of the true signal and the observation window, and measurements using the FWHM can yield biased results...
July 18, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28728780/detecting-regional-stiffness-changes-in-aortic-aneurysmal-geometries-using-pressure-normalized-strain
#2
Doran S Mix, Ling Yang, Camille C Johnson, Nathan Couper, Ben Zarras, Isaac Arabadjis, Lauren E Trakimas, Michael C Stoner, Steven W Day, Michael S Richards
Transabdominal ultrasound elasticity imaging could improve the assessment of rupture risk for abdominal aortic aneurysms by providing information on the mechanical properties and stress or strain states of vessel walls. We implemented a non-rigid image registration method to visualize the pressure-normalized strain within vascular tissues and adapted it to measure total strain over an entire cardiac cycle. We validated the algorithm's performance with both simulated ultrasound images with known principal strains and anatomically accurate heterogeneous polyvinyl alcohol cryogel vessel phantoms...
July 17, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28720285/ultrasound-based-shear-wave-elastography-in-the-assessment-of-patients-with-diabetic-kidney-disease
#3
Flaviu Bob, Iulia Grosu, Ioan Sporea, Simona Bota, Alina Popescu, Alexandra Sima, Roxana Şirli, Ligia Petrica, Romulus Timar, Adalbert Schiller
In previous studies of acoustic radiation force impulse (ARFI) elastography, using Virtual Touch tissue quantification (VTQ) (Siemens Acuson S2000), it was reported that the measurement of renal shear wave speed in patients with chronic kidney disease (CKD) is not influenced exclusively by renal fibrosis. The purpose of the present study was to analyze the role of VTQ in patients with diabetic kidney disease, considered the main cause of CKD. The study group included 164 patients: 80 patients with diabetic kidney disease (DKD) and 84 without renal disease or diabetes mellitus...
July 15, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28716434/training-midwives-to-perform-basic-obstetric-point-of-care-ultrasound-in-rural-areas-using-a-tablet-platform-and-mobile-phone-transmission-technology-a-wfumb-coe-project
#4
Sudhir Vinayak, Joyce Sande, Harvey Nisenbaum, Christian Pállson Nolsøe
Point-of-care ultrasound (POCUS) has become a topical subject and can be applied in a variety of ways with differing outcomes. The cost of all diagnostic procedures including obstetric ultrasound examinations is a major factor in the developing world and POCUS is only useful if it can be equated to good outcomes at a lower cost than a routine obstetric examination. The aim of this study was to assess a number of processes including accuracy of images and reports generated by midwives, performance of a tablet-sized ultrasound scanner, training of midwives to complete ultrasounds, teleradiology solution transmissions of images via internet, review of images by a radiologist, communication between midwife and radiologist, use of this technique to identify high-risk patients and improvement of the education and teleradiology model components...
July 14, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28716433/unmyelinated-peripheral-nerves-can-be-stimulated-in%C3%A2-vitro-using-pulsed-ultrasound
#5
Christopher J Wright, Seyyed R Haqshenas, John Rothwell, Nader Saffari
Appreciation for the medical and research potential of ultrasound neuromodulation is growing rapidly, with potential applications in non-invasive treatment of neurodegenerative disease and functional brain mapping spurring recent progress. However, little progress has been made in our understanding of the ultrasound-tissue interaction. The current study tackles this issue by measuring compound action potentials (CAPs) from an ex vivo crab walking leg nerve bundle and analysing the acoustic nature of successful stimuli using a passive cavitation detector (PCD)...
July 14, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28716432/effect-of-frequency-and-focal-spacing-on-transcranial-histotripsy-clot-liquefaction-using-electronic-focal-steering
#6
Tyler Gerhardson, Jonathan R Sukovich, Aditya S Pandey, Timothy L Hall, Charles A Cain, Zhen Xu
This in vitro study investigated the effects of ultrasound frequency and focal spacing on blood clot liquefaction via transcranial histotripsy. Histotripsy pulses were delivered using two 256-element hemispherical transducers of different frequency (250 and 500 kHz) with 30-cm aperture diameters. A 4-cm diameter spherical volume of in vitro blood clot was treated through 3 excised human skullcaps by electronically steering the focus with frequency proportional focal spacing: λ/2, 2 λ/3 and λ with 50 pulses per location...
July 14, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28716431/freehand-3-d-ultrasound-imaging-a-systematic-review
#7
REVIEW
Mohammad Hamed Mozaffari, Won-Sook Lee
Two-dimensional ultrasound (US) imaging has been successfully used in clinical applications as a low-cost, portable and non-invasive image modality for more than three decades. Recent advances in computer science and technology illustrate the promise of the 3-D US modality as a medical imaging technique that is comparable to other prevalent modalities and that overcomes certain drawbacks of 2-D US. This systematic review covers freehand 3-D US imaging between 1970 and 2017, highlighting the current trends in research fields, the research methods, the main limitations, the leading researchers, standard assessment criteria and clinical applications...
July 14, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28716430/non-invasive-evaluation-of-right-ventricular-function-with-real-time-3-d-echocardiography
#8
Ran Chen, Meihua Zhu, Kacie Amacher, Xia Wu, David J Sahn, Muhammad Ashraf
The aim of this study was to evaluate the accuracy and feasibility of real-time 3-D echocardiography (3-DE) in assessing right ventricular (RV) systolic function. A latex balloon was inserted into the right ventricle of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus. The RV global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and RV ejection fraction (RVEF), derived from 3-DE, as well as the RVEF obtained from 2-D echocardiography (2-DE) were quantified at different stroke volumes (30-70 mL) and compared with sonomicrometry data...
July 14, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28711283/common-carotid-artery-flow-measured-by-3-d-ultrasonic-vector-flow-imaging-and-validated-with-magnetic-resonance-imaging
#9
Simon Holbek, Kristoffer Lindskov Hansen, Hamed Bouzari, Caroline Ewertsen, Matthias Bo Stuart, Carsten Thomsen, Michael Bachmann Nielsen, Jørgen Arendt Jensen
Ultrasound (US) examination of the common carotid artery was compared with a through-plane magnetic resonance imaging (MRI) sequence to validate a recently proposed technique for 3-D US vector flow imaging. Data from the first volunteer examined were used as the training set, before volume flow and peak velocities were calculated for the remaining eight volunteers. Peak systolic velocities (PSVs) and volume flow obtained with 3-D US were, on average, 34% higher and 24% lower than those obtained with MRI, respectively...
July 12, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28705557/automatic-identification-of-the-optimal-reference-frame-for-segmentation-and-quantification-of-focal-liver-lesions-in-contrast-enhanced-ultrasound
#10
Spyridon Bakas, Dimitrios Makris, Gordon J A Hunter, Cheng Fang, Paul S Sidhu, Katerina Chatzimichail
Post-examination interpretation of contrast-enhanced ultrasound (CEUS) cineloops of focal liver lesions (FLLs) requires offline manual assessment by experienced radiologists, which is time-consuming and generates subjective results. Such assessment usually starts by manually identifying a reference frame, where FLL and healthy parenchyma are well-distinguished. This study proposes an automatic computational method to objectively identify the optimal reference frame for distinguishing and hence delineating an FLL, by statistically analyzing the temporal intensity variation across the spatially discretized ultrasonographic image...
July 10, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28705556/supersonic-shear-wave-imaging-of-the-spleen-for-staging-of-liver-fibrosis-in-rats
#11
Xiang-Dong Hu, Hui-Ying Geng, Lei Wang, Hu-Feng Xu, Yuan Su, Si Liang, Lin-Xue Qian
The goal of the work described here was to explore the cause of spleen stiffness (SS) in hepatic fibrogenesis and evaluate the value of SS in liver fibrosis (LF) staging. LF was induced with carbon tetrachloride (CCl4) in rats (n = 40). Supersonic shear wave imaging and contrast-enhanced ultrasound were performed to determine liver stiffness (LS), SS and splenic hemodynamics. SS, LS and free portal pressure exhibited moderate correlations with fibrosis stage (r = 0.744-0.835, p < 0.001). Time-intensity curves of contrast-enhanced ultrasound for the spleen were presented as decreasing peak intensity and slope of decrease, and increasing time to peak...
July 10, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28705555/sonodynamic-therapy-based-on-combined-use-of-low-dose-administration-of-epirubicin-incorporating-drug-delivery-system-and-focused-ultrasound
#12
Masanori Maeda, Yoshihiro Muragaki, Jun Okamoto, Shin Yoshizawa, Nobutaka Abe, Hidekazu Nakamoto, Hiroshi Ishii, Kenichi Kawabata, Shinichiro Umemura, Nobuhiro Nishiyama, Kazunori Kataoka, Hiroshi Iseki
Sonodynamic therapy (SDT) is currently considered as one of the promising minimally invasive treatment options for solid cancers. SDT is based on the combined use of a sonosensitizer drug and high-intensity focused ultrasound (HIFU) to produce cytotoxic reactive oxygen species (ROS) in and around neoplastic cells. Anthracycline drugs, including epirubicin (EPI), have been well known as effective sonosensitizers after interaction with focused ultrasound. Recently a new anticancer drug delivery system (DDS), NC-6300, has been developed that comprises EPI through an acid-labile hydrazone bond...
July 10, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28693906/reproducible-computer-assisted-quantification-of-myocardial-perfusion-with-contrast-enhanced-ultrasound
#13
Yuanwei Li, Navtej Chahal, Roxy Senior, Meng-Xing Tang
Myocardial perfusion can be quantified by myocardial contrast echocardiography (MCE) and is used for the diagnosis of coronary artery disease (CAD). However, existing MCE quantification software is highly operator dependent and has poor reproducibility and ease of usage. The aim of this study was to develop robust and easy-to-use software that can perform MCE quantification accurately, reproducibly and rapidly. The developed software has the following features: (i) semi-automatic segmentation of the myocardium; (ii) automatic rejection of MCE data with poor image quality; (iii) automatic computation of perfusion parameters such as myocardial blood flow (MBF)...
July 7, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28693905/a-temporal-and-spatial-analysis-approach-to-automated-segmentation-of-microbubble-signals-in-contrast-enhanced-ultrasound-images-application-to-quantification-of-active-vascular-density-in-human-lower-limbs
#14
Wing Keung Cheung, Katherine J Williams, Kirsten Christensen-Jeffries, Brahman Dharmarajah, Robert J Eckersley, Alun H Davies, Meng-Xing Tang
Contrast-enhanced ultrasound (CEUS) using microbubble contrast agents has shown great promise in visualising and quantifying active vascular density. Most existing approaches for vascular density quantification using CEUS are calculated based on image intensity and are susceptible to confounding factors and imaging artefact. Poor reproducibility is a key challenge to clinical translation. In this study, a new automated temporal and spatial signal analysis approach is developed for reproducible microbubble segmentation and quantification of contrast enhancement in human lower limbs...
July 7, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28689675/hypothesis-of-improved-visualization-of-microstructures-in-the-interventricular-septum-with-ultrasound-and-adaptive-beamforming
#15
Ole Marius Hoel Rindal, Svend Aakhus, Sverre Holm, Andreas Austeng
In this work, in vivo ultrasound cardiac images created with Capon's minimum variance adaptive beamformer are compared with images acquired with the conventional delay-and-sum beamformer. Specifically, we provide three views of a human heart imaged through the parasternal short-axis, the parasternal long-axis and the apical four-chamber views. The minimum variance beamformer produced images with improved lateral resolution, resulting in better resolved speckle structure and improved edges, especially on close investigation of the interventricular septum...
July 6, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28684185/transabdominal-ultrasound-colonography-for-detection-of-colorectal-neoplasms-initial-clinical-experience
#16
Jin-Ya Liu, Li-Da Chen, Jian-Bo Xu, Hui Wu, Jin-Ning Ye, Xin-Hua Zhang, Xiao-Yan Xie, Wei Wang, Ming-De Lu
We investigated the feasibility of using ultrasound colonography (USC) to visualize the healthy colon and rectum and detect colorectal polyps. Eight healthy volunteers underwent USC after standard bowel preparation. The feasibility and image quality of USC in different segments were evaluated. Then, USC was conducted on eight patients with known colonic neoplasms using colonoscopy as the reference standard. For volunteers, USC examinations were successfully performed on four (50.0%) ascending, three (37.5%) transverse and eight (100%) descending colons, as well as all sigmoid colons and rectums...
July 3, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28684184/quantitative-analysis-of-hepatic-microcirculation-in%C3%A2-rabbits%C3%A2-after-liver-ischemia-reperfusion-injury%C3%A2-using%C3%A2-contrast-enhanced-ultrasound
#17
Haiyuan Li, Jingning Lu, Xiaofeng Zhou, Denghua Pan, Dequan Guo, Haiying Ling, Hong Yang, Yun He, Gang Chen
Previous studies have shown that contrast-enhanced ultrasound (CEUS) can be used quantitatively to analyze microcirculation blood perfusion in hepatocellular carcinoma patients. However, limited data have described the application of CEUS in hepatic microcirculation after liver ischemic-reperfusion injury (IRI). The purpose of this study was to explore the use of CEUS quantitatively to assess liver microcirculation after liver IRI. We randomly sorted 45 New Zealand rabbits into 3 groups (15 in each). Group A was a control group in which the rabbits underwent laparotomy alone...
July 3, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28673478/comparing-performance-of-combinations-of-shear-wave-elastography-and-b-mode-ultrasound-in-diagnosing-breast-masses-is-it-influenced-by-mass-size
#18
Rui Cong, Jing Li, Xuejiao Wang
We determined the diagnostic performance of combinations of shear wave elastography (SWE) and B-mode ultrasound (US) in differentiating malignant from benign breast masses, and we investigated whether performance is affected by mass size. In this prospective study of 315 consecutive patients with 326 breast masses, US and SWE were performed before biopsy. Masses were categorized into two subgroups on the basis of mass size (≤15 mm and >15 mm), and the optimal thresholds for the SWE parameters were determined for each subgroup using receiver operating characteristic curves...
June 30, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28673477/image-monitoring-of-the-impaired-phagocytic-activity-of%C3%A2-kupffer-cells-and-liver-oxygen-saturation-in-a-mouse-cholangitis-model-using-contrast-enhanced-ultrasound-imaging-and-photoacoustic-imaging
#19
Seunghyun Lee, Jung Hoon Kim, Jae Hwan Lee, Seo-Youn Choi
Bile duct ligation (BDL) can cause cholangitis, which is known to induce impaired Kupffer cell (KC) function and increased oxygen consumption in a mouse model. It is important to monitor changes in KC function and tissue oxygen saturation, both of which are critical factors in the progression of cholangitis. The purpose of this study is to investigate the impaired phagocytic activity of KC and liver oxygen saturation (sO2) in a mouse cholangitis model using contrast-enhanced ultrasound imaging (CEUS) and photoacoustic imaging (PAI)...
June 30, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28673476/prediction-for-improvement-and-remodeling-in-first-onset-myocardial-infarction-by-speckle-tracking-echocardiography-is-global-or-regional-selection-better
#20
Bo Hu, Qing Zhou, Jinling Chen, Tuantuan Tan, Xue Yao, Hongning Song, Ruiqiang Guo
Cardiac function improvement and chamber remodeling after the onset of acute myocardial infarction (AMI) is crucial as it is closely related to the outcomes of patients. We sought to investigate the predictive value of left ventricular (LV) global and region of interest (ROI) assessment for prognosis of AMI patients by speckle tracking echocardiography (STE). We prospectively enrolled 81 first-onset AMI patients for baseline and 6-mo follow-up analysis. The echocardiography-derived parameters were compared in receiver operator characteristics (ROC) analysis for prediction of LV remodeling (LVR) (a minimum 20% increase of LV end-diastolic volume) and cardiac function improvement (a minimum 5% increase of LV ejection fraction)...
June 30, 2017: Ultrasound in Medicine & Biology
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