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https://www.readbyqxmd.com/read/28092531/a-200-1380-khz-quadrifrequency-focused-ultrasound-transducer-for-neurostimulation-in-rodents-and-primates-transcranial-in-vitro-calibration-and-numerical-study-of-the-influence-of-skull-cavity
#1
Charlotte Constans, Thomas Deffieux, Pierre Pouget, Mickael Tanter, Jean-Francois Aubry
Low intensity transcranial focused ultrasound has been demonstrated to produce neuromodulation in both animals and humans. Primarily for technical reasons, frequency is one of the most poorly investigated critical wave parameters. We propose the use of a quadri-band transducer capable of operating at 200, 320, 850 and 1380 kHz for further investigation of the frequency dependence of neuromodulation efficacy while keeping the position of the transducer fixed with respect to the subject's head. This paper presents the results of the transducer calibration in water, in vitro transmission measurements through a monkey skull flap, 3D simulations based on both a μCT-scan of a rat and on CT-scans of 2 macaques...
January 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28091280/rotation-elastogram-estimation-using-synthetic-transmit-aperture-technique
#2
Lokesh B, Bhaskara Rao Chintada, Arun Kumar Thittai
It is well-documented in literature that benign breast lesions, such as fibroadenomas, are loosely bonded to their surrounding tissue and tend to slip under a small quasi-static compression, whereas malignant lesions being firmly bonded to their surrounding tissue do not slip. Recent developments in quasi-static ultrasound elastography have shown that an image of the axial-shear strain distribution can provide information about the bonding condition at the lesion-surrounding tissue boundary. Further studies analyzing the axial-shear strain elastograms revealed that nonzero axial-shear strain values appear inside the lesion, referred to as fill-in, only when a lesion is loosely bonded and asymmetrically oriented to the axis of compression...
January 1, 2017: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28090656/real-time-monitoring-of-tissue-displacement-and-temperature-changes-during-mr-guided-high-intensity-focused-ultrasound
#3
Pierre Bour, Fabrice Marquet, Valéry Ozenne, Solenn Toupin, Erik Dumont, Jean-François Aubry, Matthieu Lepetit-Coiffe, Bruno Quesson
PURPOSE: The therapy endpoint most commonly used in MR-guided high intensity focused ultrasound is the thermal dose. Although namely correlated with nonviable tissue, it does not account for changes in mechanical properties of tissue during ablation. This study presents a new acquisition sequence for multislice, subsecond and simultaneous imaging of tissue temperature and displacement during ablation. METHODS: A single-shot echo planar imaging sequence was implemented using a pair of motion-encoding gradients, with alternated polarities...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28088840/evaluation-of-a-short-term-training-program-in-bedside-emergency-ultrasound-in-southwestern-tanzania
#4
Mark Shaffer, Heather A Brown, Chloé McCoy, Prosper Bashaka
OBJECTIVES: To evaluate the effect of a short-term training program in emergency ultrasound on physician skills and attitudes in southwestern Tanzania. METHODS: Eight registrar physicians at Mbeya Zonal Referral Hospital (Mbeya, Tanzania) underwent a 5-day course in bedside emergency ultrasound, focusing primarily on the focused assessment with sonography for trauma examination, including didactic sessions, practical sessions, and on-job training. The impact on ultrasound knowledge was assessed by pretest and posttest evaluations...
January 15, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/28076337/coded-excitation-for-diverging-wave-cardiac-imaging-a-feasibility-study
#5
Feifei Zhao, Ling Tong, Qiong He, Jianwen Luo
Diverging wave (DW) based cardiac imaging has gained increasing interest in recent years given its capacity to achieve ultrahigh frame rate. However, the signal-to-noise ratio (SNR), contrast, and penetration depth of the resulting B-mode images are typically low as DWs spread energy over a large region. Coded excitation is known to be capable of increasing the SNR and penetration for ultrasound imaging. The aim of this study was therefore to test the feasibility of applying coded excitation in DW imaging to improve the corresponding SNR, contrast and penetration depth...
January 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28072580/in-vivo-real-time-cavitation-imaging-in-moving-organs
#6
B Arnal, J Baranger, C Demene, M Tanter, M Pernot
The stochastic nature of cavitation implies visualization of the cavitation cloud in real-time and in a discriminative manner for the safe use of focused ultrasound therapy. This visualization is sometimes possible with standard echography, but it strongly depends on the quality of the scanner, and is hindered by difficulty in discriminating from highly reflecting tissue signals in different organs. A specific approach would then permit clear validation of the cavitation position and activity. Detecting signals from a specific source with high sensitivity is a major problem in ultrasound imaging...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28072572/a-3d-time-reversal-cavity-for-the-focusing-of-high-intensity-ultrasound-pulses-over-a-large-volume
#7
J Robin, B Arnal, M Tanter, M Pernot
Shock wave ultrasound therapy techniques, increasingly used for non-invasive surgery, require extremely high pressure amplitudes in precise focal spots, and large high-power transducers arranged on a spherical shell are usually used to achieve that. This solution allows limited steering of the beam around the geometrical focus of the device at the cost of a large number of transducer elements, and the treatment of large and moving organs like the heart is challenging or impossible. This paper validates numerically and experimentally the possibility of using a time reversal cavity (TRC) for the same purpose...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28070760/the-generation-r-study-design-and-cohort-update-2017
#8
Marjolein N Kooijman, Claudia J Kruithof, Cornelia M van Duijn, Liesbeth Duijts, Oscar H Franco, Marinus H van IJzendoorn, Johan C de Jongste, Caroline C W Klaver, Aad van der Lugt, Johan P Mackenbach, Henriëtte A Moll, Robin P Peeters, Hein Raat, Edmond H H M Rings, Fernando Rivadeneira, Marc P van der Schroeff, Eric A P Steegers, Henning Tiemeier, André G Uitterlinden, Frank C Verhulst, Eppo Wolvius, Janine F Felix, Vincent W V Jaddoe
The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. This multidisciplinary study focuses on several health outcomes including behaviour and cognition, body composition, eye development, growth, hearing, heart and vascular development, infectious disease and immunity, oral health and facial growth, respiratory health, allergy and skin disorders of children and their parents...
December 2016: European Journal of Epidemiology
https://www.readbyqxmd.com/read/28069224/a-method-for-water-well-regeneration-based-on-shock-waves-and-ultrasound
#9
Anna V Abramova, Vladimir O Abramov, Vadim M Bayazitov, Roman V Nikonov
The regeneration of water wells is an urgent problem nowadays, when drilling of new wells becomes more and more expensive. Formation damage leads to a reduction of the formation's permeability and/or pore volume which in turn inhibits the ability of the water to flow from the reservoir formation into the wellbore. A new technology that uses high-power ultrasound to remove formation damage of water wells has been developed. The effectiveness of regeneration of wells can be enhanced if ultrasound and shockwaves are used during the same treatment...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069222/ultrasound-assisted-extraction-of-bioactive-compounds-from-palm-pressed-fiber-with-high-antioxidant-and-photoprotective-activities
#10
Valéria Dal Prá, Felipe C Lunelli, Raquel Guidetti Vendruscolo, Rafael Martins, Roger Wagner, Ayres P Lazzaretti, Denise M Guimarães Freire, Maria Alexandri, Apostolis Koutinas, Marcio A Mazutti, Marcelo Barcellos da Rosa
This work is focused on the optimization of the ultrasound-assisted extraction of antioxidant compounds with photoprotective effect from palm pressed fiber. The influence of ultrasound intensity and pulse cycle was investigated by means of a central composite rotational design. The optimized condition was ultrasound intensity of 120W.cm(-2) and pulse factor of 0.4, yielding 3.24wt%. Compounds such as fatty acids, β-sitosterol, α-tocopherol, squalene, total phenolics and carotene were identified. The extract presented antioxidant activity towards synthetic (2,2-diphenyl-1-picrylhydrazyl - DPPH, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) - ABTS) and biological radicals (Hydroxyl - OH), besides a sun protection factor of 15...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069221/effects-of-different-hydrostatic-pressure-on-lesions-in-ex-vivo-bovine-livers-induced-by-high-intensity-focused-ultrasound
#11
Min He, Zhiqiang Zhong, Xing Li, Xiaobo Gong, Zhibiao Wang, Faqi Li
It is well-known that acoustic cavitation associated with the high intensity focused ultrasound (HIFU) treatment often would change the morphology and size of lesions in its treatment. In most studies reported in literature, high ambient hydrostatic pressure was used to suppress the cavitation completely. Investigation of the effects by varying the ambient hydrostatic pressure (Pstat) is still lacking. In this paper, the effects of HIFU on lesions in ex vivo bovine liver specimens under various Pstat are systematically investigated...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069215/intensification-of-esterification-of-non-edible-oil-as-sustainable-feedstock-using-cavitational-reactors
#12
Ashish V Mohod, Abhijeet S Subudhi, Parag R Gogate
Using sustainable feed stock such as non-edible oil for the biodiesel production can be one of the cost effective approaches considering the ever growing interest towards renewable energy and problems in existing approaches for production. However, due to the high free fatty acid content, non-edible oils require considerable preprocessing before the actual transesterification reaction for biodiesel production. The present work focuses on intensification of the esterification reaction used as preprocessing step based on acoustic and hydrodynamic cavitation also presenting the comparison with the conventional approach...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069201/pulsed-wave-low-dose-ultrasound-hyperthermia-selectively-enhances-nanodrug-delivery-and-improves-antitumor-efficacy-for-brain-metastasis-of-breast-cancer
#13
Sheng-Kai Wu, Chi-Feng Chiang, Yu-Hone Hsu, Houng-Chi Liou, Wen-Mei Fu, Win-Li Lin
The clinical application of chemotherapeutics for brain tumors remains a challenge due to limitation of blood-brain barrier/blood-tumor barrier (BBB/BTB). In this study, we investigated the effects of low-dose focused ultrasound hyperthermia (UH) on the delivery and therapeutic efficacy of pegylated liposomal doxorubicin (PLD) for brain metastasis of breast cancer. Murine breast cancer cells (4T1-luc2) expressing firefly luciferase were implanted into mouse striatum as a brain tumor model. The mice were intravenously injected with PLD with/without transcranial pulsed-wave/continuous-wave UH (pUH/cUH) treatment on day-6 after tumor implantation...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069193/safety-of-ultrasound-guided-high-intensity-focused-ultrasound-ablation-for-diffuse-adenomyosis-a-retrospective-cohort-study
#14
Yujie Feng, Liang Hu, Wenzhi Chen, Rong Zhang, Xi Wang, Jinyun Chen
OBJECTIVES: To evaluate the safety of ultrasound-guided high-intensity focused ultrasound (HIFU) ablation for patients with diffuse adenomyosis. METHODS: This was a retrospective cohort study. The data was collected from 417 symptomatic adenomyosis patients who underwent ultrasound-guided HIFU between January 2012 and December 2015 at 1st Affiliated Hospital of Chongqing Medical University, Chongqing, China. Among them were 260 patients with diffuse adenomyosis (Group D) and 157 patients with focal adenomyosis (Group F)...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069188/simulation-of-phase-separation-with-large-component-ratio-for-oil-in-water-emulsion-in-ultrasound-field
#15
Heping Wang, Xiaoguang Li, Yanggui Li, Xingguo Geng
This paper presents an exploration for separation of oil-in-water and coalescence of oil droplets in ultrasound field via lattice Boltzmann method. Simulations were conducted by the ultrasound traveling and standing waves to enhance oil separation and trap oil droplets. The focus was to the effect of ultrasound irradiation on oil-in-water emulsion properties in the standing wave field, such as oil drop radius, morphology and growth kinetics of phase separation. Ultrasound fields were applied to irradiate the oil-in-water emulsion for getting flocculation of the oil droplets in 420kHz case, and larger dispersed oil droplets and continuous phases in 2MHz and 10MHz cases, respectively...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28068874/short-lag-spatial-coherence-ultrasound-imaging-with-adaptive-synthetic-transmit-aperture-focusing
#16
Jinxin Zhao, Yuanyuan Wang, Jinhua Yu, Wei Guo, Shun Zhang, Saeid Aliabadi
The short-lag spatial coherence (SLSC) imaging has been demonstrated to be advantageous over the traditional B-mode ultrasound imaging. With focused scanning beams, the SLSC imaging has an excellent performance in clutter reduction and lesion detection, especially in the low signal-to-noise ratio (SNR) scenarios. The synthetic aperture (SA) imaging is an appropriate mode for the SLSC imaging as the dynamic transmit focusing could keep a good focusing quality at any depth. However, the SLSC image may still suffer a bad resolution performance when a low lag value is used in the coherence summation to ensure the contrast enhancement...
January 1, 2017: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28067975/assessment-of-acute-thermal-damage-volumes-in-muscle-using-magnetization-prepared-3d-t2-weighted-imaging-following-mri-guided-high-intensity-focused-ultrasound-therapy
#17
Robert M Staruch, Joris Nofiele, Jamie Walker, Chenchen Bing, Ananth J Madhuranthakam, April Bailey, Young-Sun Kim, Avneesh Chhabra, Dennis Burns, Rajiv Chopra
PURPOSE: To evaluate magnetization-prepared 3D T2 -weighted magnetic resonance imaging (MRI) measurements of acute tissue changes produced during ablative MR high-intensity focused ultrasound (MR-HIFU) exposures. MATERIALS AND METHODS: A clinical MR-HIFU system (3T) was used to generate thermal lesions (n = 24) in the skeletal muscles of three pigs. T1 -weighted, 2D T2 -weighted, and magnetization-prepared 3D T2 -weighted sequences were acquired before and after therapy to evaluate tissue changes following ablation...
January 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28063909/periprocedural-outcomes-comparing-fibroid-embolization-and-focused-ultrasound-a-randomized-controlled-trial-and-comprehensive-cohort-analysis
#18
Emily P Barnard, Ahmed M AbdElmagied, Lisa E Vaughan, Amy L Weaver, Shannon K Laughlin-Tommaso, Gina K Hesley, David A Woodrum, Vanessa L Jacoby, Maureen P Kohi, Thomas M Price, Angel Nieves, Michael J Miller, Bijan J Borah, Krzysztof R Gorny, Phyllis C Leppert, Lisa G Peterson, Elizabeth A Stewart
BACKGROUND: Uterine fibroids are a common problem for reproductive-aged women, yet little comparative effectiveness research is available to guide treatment choice. Uterine artery embolization and magnetic resonance imaging-guided focused ultrasound surgery are minimally invasive therapies approved by the United States Food and Drug Administration for treating symptomatic uterine fibroids. The Fibroid Interventions: Reducing Symptoms Today and Tomorrow study is the first randomized controlled trial to compare these 2 fibroid treatments...
January 4, 2017: American Journal of Obstetrics and Gynecology
https://www.readbyqxmd.com/read/28063191/salvage-high-intensity-focused-ultrasound-hifu-for-locally-recurrent-prostate-cancer-after-failed-radiation-therapy-multi-institutional-analysis-of-418-patients
#19
Sebastien Crouzet, Andreas Blana, Francois J Murat, Gilles Pasticier, Stephen C W Brown, Giario N Conti, Roman Ganzer, Olivier Chapet, Albert Gelet, Christian G Chaussy, Cary N Robertson, Stefan Thuroff, John F Ward
OBJECTIVE: To report the oncological outcome of Salvage high-intensity focused ultrasound (S-HIFU) for locally recurrent prostate cancer (PCa) following External Beam Radiotherapy (EBRT) from a multicenter database. MATERIALS AND METHODS: This retrospective study comprises patients from 9 centers with local recurrent disease following EBRT treated with S-HIFU from 1995 to 2009. Biochemical free survival rates (BFSR) was based on the "Phoenix" definition (nadir+2)...
January 7, 2017: BJU International
https://www.readbyqxmd.com/read/28063115/bedside-focused-cardiac-ultrasound-in-the-evaluation-of-systolic-dysfunction
#20
Elisa Maria Fiorelli, Francesco Casella, Daniela Torzillo, Chiara Cogliati
No abstract text is available yet for this article.
January 6, 2017: Internal and Emergency Medicine
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