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https://www.readbyqxmd.com/read/28436857/real-time-triple-modal-photoacoustic-ultrasound-and-magnetic-resonance-fusion-imaging-of-humans
#1
Sara Park, Jongseong Jang, Jeesu Kim, Young Soo Kim, Chulhong Kim
Imaging that fuses multiple modes has become a useful tool for diagnosis and therapeutic monitoring. As a next step, real-time fusion imaging has attracted interest as for a tool to guide surgery. One widespread fusion imaging technique in surgery combines real-time ultrasound (US) imaging and preacquired magnetic resonance (MR) imaging. However, US imaging visualizes only structural information with relatively low contrast. Here, we present a photoacoustic (PA), US, and MR fusion imaging system which integrates a clinical PA and US imaging system with an optical tracking-based navigation subsystem...
April 24, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28436843/fabrication-and-performance-of-a-miniaturized-and-integrated-endoscope-ultrasound-convex-array-for-digestive-tract-imaging
#2
Jue Peng, Xiaojian Peng, Hu Tang, Xiaozhen Li, Ruimin Chen, Yang Li, Tianfu Wang, Siping Chen, Koping Shung, Qifa Zhou
OBJECTIVE: This work presents the design, fabrication and testing of a miniaturized and integrated ultrasound endoscope for use as an in situ digestive diagnostic device to facilitate real-time ultrasound guidance of intervention treatments. METHODS: We designed an optimal structure to integrate an auto-focus 5-megapixel camera module with an 8-MHz, 64-element curvilinear ultrasonic array in one miniaturized package. A novel three-axis auto-focusing voice coil motor (VCM) was designed and manufactured for the camera module to move the lens position for auto-focusing and to adjust the lens tilt...
April 24, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28433440/spatial-compounding-technique-to-obtain-rotation-elastogram-a-feasibility-study
#3
AliArshad Kothawala, Sowmiya Chandramoorthi, N Ravi Kiran Reddy, Arun Kumar Thittai
The perception of stiffness and slipperiness of a breast mass on palpation is used by physicians to assess the level of suspicion of a lesion as being malignant or benign. However, most current ultrasound elastography imaging methods provide only stiffness-related information. There is no existing approach that provides information about the local rigid body rotation undergone by only a loosely bonded, asymmetrically oriented lesion subjected to a small quasi-static compression. The inherent poor lateral resolution in ultrasound imaging poses a limitation in estimating the local rigid body rotation...
April 19, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28432447/twofold-minimum-variance-beamforming-for-enhanced-ultrasound-imaging
#4
Sayed Mahmoud Sakhaei, Seyede Elham Shamsian
PURPOSE: To calculate the optimal weights of a minimum variance (MV) beamformer, the covariance matrix of the received data should be estimated. In ultrasound imaging, it is done through spatial smoothing. However, this technique reduces the effective aperture and consequently limits the attainable resolution. To mitigate this effect, we propose a new configuration for applying an adaptive beamforming method. METHODS: The method is based on applying MV in a twofold configuration such that the outputs of the subarrays are combined through an adaptive MV-like beamformer, instead of simply summing them...
April 21, 2017: Journal of Medical Ultrasonics
https://www.readbyqxmd.com/read/28430318/teaching-medical-students-ultrasound-guided-vascular-access-which-learning-method-is-best
#5
Alwin Lian, James C R Rippey, Peter J Carr
INTRODUCTION: Ultrasound is recommended to guide insertion of peripheral intravenous vascular cannulae (PIVC) where difficulty is experienced. Ultrasound machines are now common-place and junior doctors are often expected to be able to use them. The educational standards for this skill are highly varied, ranging from no education, to self-guided internet-based education, to formal, face-to-face traditional education. In an attempt to decide which educational technique our institution should introduce, a small pilot trial comparing educational techniques was designed...
April 20, 2017: Journal of Vascular Access
https://www.readbyqxmd.com/read/28426437/supersonic-transient-magnetic-resonance-elastography-for-quantitative-assessment-of-tissue-elasticity
#6
Yu Liu, Jingfei Liu, Brett Z Fite, Josquin Foiret, Asaf Ilovitsh, J Kent Leach, Erik Dumont, Charles F Caskey, Katherine W Ferrara
Non-invasive, quantitative methods to assess the properties of biological tissues are needed for many therapeutic and tissue engineering applications. Magnetic resonance elastography (MRE) has historically relied on external vibration to generate periodic shear waves. In order to focally assess a biomaterial or to monitor the response to ablative therapy, the interrogation of a specific region of interest by a focused beam is desirable and transient MRE (t-MRE) techniques have previously been developed to accomplish this goal...
April 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28425388/lower-bound-on-estimation-variance-of-the-ultrasonic-attenuation-coefficient-using-the-spectral-difference-reference-phantom-method
#7
Kayvan Samimi, Tomy Varghese
Ultrasonic attenuation is one of the primary parameters of interest in Quantitative Ultrasound (QUS). Non-invasive monitoring of tissue attenuation can provide valuable diagnostic and prognostic information to the physician. The Reference Phantom Method (RPM) was introduced as a way of mitigating some of the system-related effects and biases to facilitate clinical QUS applications. In this paper, under the assumption of diffuse scattering, a probabilistic model of the backscattered signal spectrum is used to derive a theoretical lower bound on the estimation variance of the attenuation coefficient using the Spectral-Difference RPM...
May 2017: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28415122/p1138cardiac-shear-wave-velocity-in-healthy-individuals
#8
M Strachinaru, M L Geleijnse, J G Bosch, N De Jong, Afw Van Der Steen, B M Van Dalen, H J Vos
Background: The closure of the valves generates shear waves in the heart walls. The propagation velocity of shear waves relates to stiffness. This could potentially be used to estimate the stiffness of the myocardium, with huge potential implications in pathologies characterized by a deterioration of the diastolic properties of the left ventricle. In an earlier phantom study we already validated shear wave tracking with a clinical ultrasound system in cardiac mode. Purpose: In this study we aimed to measure the shear waves velocity in normal individuals...
December 1, 2016: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28414927/integration-of-free-hand-3d-ultrasound-and-mobile-c-arm-cone-beam-ct-feasibility-and-characterization-for-real-time-guidance-of-needle-insertion
#9
E Marinetto, A Uneri, T De Silva, S Reaungamornrat, W Zbijewski, A Sisniega, S Vogt, G Kleinszig, J Pascau, J H Siewerdsen
This work presents development of an integrated ultrasound (US)-cone-beam CT (CBCT) system for image-guided needle interventions, combining a low-cost ultrasound system (Interson VC 7.5MHz, Pleasanton, CA) with a mobile C-arm for fluoroscopy and CBCT via use of a surgical tracker. Imaging performance of the ultrasound system was characterized in terms of depth-dependent contrast-to-noise ratio (CNR) and spatial resolution. US-CBCT system was evaluated in phantom studies simulating three needle-based procedures: drug delivery, tumor ablation, and lumbar puncture...
April 3, 2017: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/28413682/multi-focal-hifu-reduces-cavitation-in-mild-hyperthermia
#10
Vandiver Chaplin, Charles F Caskey
BACKGROUND: Mild-hyperthermia therapy (40-45 °C) with high-intensity focused ultrasound (HIFU) is a technique being considered in a number of different treatments such as thermally activated drug delivery, immune-stimulation, and as a chemotherapy adjuvant. Mechanical damage and loss of cell viability associated with HIFU-induced acoustic cavitation may pose a risk during these treatments or may hinder their success. Here we present a method that achieves mild heating and reduces cavitation by using a multi-focused HIFU beam...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28410100/estimation-of-strain-elastography-from-ultrasound-radio-frequency-data-by-utilizing-analytic-gradient-of-the-similarity-metric
#11
Mona Omidyeganeh, Yiming Xiao, M Omair Ahmad, Hassan Rivaz
Most strain imaging techniques follow a pipeline strategy: in the first step tissue displacement is estimated from radio-frequency (RF) frames, and in the second step, a spatial derivative operation is applied. There are two main issues that arise from this framework. First, the gradient operation amplifies noise, and therefore, smoothing techniques have to be adopted. Second, strain estimation does not exploit the original RF data. It rather relies solely on the noisy displacement field. In this paper, a novel technique is proposed that utilizes both the displacement field and the RF frames to accurately obtain the strain estimates...
April 6, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28408062/novel-method-for-vessel-cross-sectional-shear-wave-imaging
#12
Qiong He, Guo-Yang Li, Fu-Feng Lee, Qihao Zhang, Yanping Cao, Jianwen Luo
Many studies have investigated the applications of shear wave imaging (SWI) to vascular elastography, mainly on the longitudinal section of vessels. It is important to investigate SWI in the arterial cross section when evaluating anisotropy of the vessel wall or complete plaque composition. Here, we proposed a novel method based on the coordinate transformation and directional filter in the polar coordinate system to achieve vessel cross-sectional shear wave imaging. In particular, ultrasound radiofrequency data were transformed from the Cartesian to the polar coordinate system; the radial displacements were then estimated directly...
April 10, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28391597/contrast-enhanced-ultrasound-imaging-in-vivo-with-laser-activated-nanodroplets
#13
Heechul Yoon, Steven K Yarmoska, Alexander S Hannah, Changhan Yoon, Kristina A Hallam, Stanislav Y Emelianov
PURPOSE: This study introduces a real-time contrast-enhanced ultrasound imaging method with recently developed laser-activated nanodroplets (LANDs), a new class of phase-change nanometer-scale contrast agents that provides perceptible, sustained high-contrast with ultrasound. METHODS: In response to pulsed laser irradiation, the LANDs-, which contain liquid perfluorohexane and optical fuses-blink (vaporize and recondense). That is, they change their state from liquid nanodroplets to gas microbubbles, and then back to liquid nanodroplets...
April 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/28391195/development-of-a-low-complexity-cost-effective-digital-beamformer-architecture-for-high-frequency-ultrasound-imaging
#14
Changhan Yoon, Hyung Ham Kim, K K Shung
This paper presents a low-complexity, cost-effective digital beamformer architecture for a high-frequency ultrasound imaging system. The proposed beamformer uses a look-up-table (LUT) and linear interpolation methods for computing the dynamic receive focusing delays and a post-filtering technique to minimize hardware complexity. In the post-filtering technique, channel radio-frequency (RF) data having the same fractional delay (i.e., 16f0 resolution) are aggregated prior to interpolation. Thus, only four polyphase structure filters are required in the developed beamformer...
April 4, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28384646/enhanced-thermal-effect-using-magnetic-nano-particles-during-high-intensity-focused-ultrasound
#15
Surendra Balaji Devarakonda, Matthew R Myers, Dushyanth Giridhar, Seyed Ahmad Reza Dibaji, Rupak Kumar Banerjee
Collateral damage and long sonication times occurring during high-intensity focused ultrasound (HIFU) ablation procedures limit clinical advancement. In this reserarch, we investigated whether the use of magnetic nano-particles (mNPs) can reduce the power required to ablate tissue or, for the same power, reduce the duration of the procedure. Tissue-mimicking phantoms containing embedded thermocouples and physiologically acceptable concentrations (0%, 0.0047%, and 0.047%) of mNPs were sonicated at acoustic powers of 5...
2017: PloS One
https://www.readbyqxmd.com/read/28384210/thermal-characteristics-of-non-biological-vessel-phantoms-for-treatment-of-varicose-veins-using-high-intensity-focused-ultrasound
#16
Mi-Sun Kim, Ju-Young Kim, Si-Cheol Noh, Heung-Ho Choi
The ultrasonic treatment of varicose veins uses high-intensity focused ultrasound, in which a blood vessel is contracted by converting acoustic energy into thermal energy. In this study, we propose a phantom of varicose veins that can be applied for the efficient evaluation of ultrasonic treatment in varicose veins. The proposed phantom consisted of glycerol base tissue equivalent material, vessel mimic tube, and blood mimic substances. The vessel mimic tube was placed inner glycerol phantom and it was filled with blood mimic substances...
2017: PloS One
https://www.readbyqxmd.com/read/28383307/the-thrombolytic-effect-of-diagnostic-ultrasound-induced-microbubble-cavitation-in-acute-carotid-thromboembolism
#17
Thomas R Porter, Feng Xie, John Lof, Jeffry Powers, Francois Vignon, William Shi, Matthew White
BACKGROUND: Acute ischemic stroke is often due to thromboembolism forming over ruptured atherosclerotic plaque in the carotid artery (CA). The presence of intraluminal CA thrombus is associated with a high risk of thromboembolic cerebral ischemic events. The cavitation induced by diagnostic ultrasound high mechanical index (MI) impulses applied locally during a commercially available intravenous microbubble infusion has dissolved intravascular thrombi, especially when using longer pulse durations...
April 5, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28380924/three-dimensional-photoacoustic-imaging-via-scanning-a-one-dimensional-linear-unfocused-ultrasound-array
#18
Yi Tan, Kaiye Xia, Qiushi Ren, Changhui Li
Three-dimensional (3D) photoacoustic imaging can be achieved by a two-dimensional (2D) ultrasound array matrix. However, the 2D matrix consisting of hundreds or thousands of transducer elements makes it not only expensive, but also a big technical challenge for both probe manufacturing and parallel data acquisition. In this study, we performed the photoacoustic imaging by scanning an unfocused linear ultrasound array probe over a planar geometry, resulting in an equivalent 2D matrix probe. The phantom study demonstrated that this method substantially increased imaging quality, which has great potential for animal and clinical photoacoustic imaging...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28374282/a-randomised-crossover-study-to-compare-the-cross-sectional-and-longitudinal-approaches-to-ultrasound-guided-peripheral-venepuncture-in-a-model
#19
James Griffiths, Amadeus Carnegie, Richard Kendall, Rajeev Madan
BACKGROUND: Ultrasound-guided peripheral intravenous access may present an alternative to central or intraosseous access in patients with difficult peripheral veins. Using venepuncture of a phantom model as a proxy, we investigated whether novice ultrasound users should adopt a cross-sectional or longitudinal approach when learning to access peripheral veins under ultrasound guidance. This result would inform the development of a structured training method for this procedure. METHODS: We conducted a randomised controlled trial of 30 medical students...
December 2017: Critical Ultrasound Journal
https://www.readbyqxmd.com/read/28374060/possible-utility-of-contrast-enhanced-ultrasonography-for-detecting-spread-of-local-anesthetic-in-nerve-block
#20
Hideaki Sasaki, Masanori Yamauchi, Takafumi Ninomiya, Haruyuki Tatsumi, Michiaki Yamakage
PURPOSE: This study demonstrated the effects of perfluorobutane (Sonazoid(®)) with contrast-enhanced ultrasonography (CEUS) to identify the spread of local anesthetics in ultrasound-guided nerve block. METHODS: This study consists of simulation, cadaveric, and animal studies. In a simulation study, 1% lidocaine with 10- to 1000-fold diluted Sonazoid(®), a US-specific contrast agent to diagnose hepatic and breast cancers (0.5 mL), was injected into a resin-based phantom to determine the optimal concentration for ultrasound-guided peripheral nerve block...
April 3, 2017: Journal of Anesthesia
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