Acoustic Analysis of Ultrasound Contrast Agents PDF Download

Author: Michał Mleczko
Publisher:
ISBN: 9783868539172
Category :
Languages : de
Pages : 187

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Author: L. Hoff
Publisher: Springer Science & Business Media
ISBN: 9401706131
Category : Medical
Languages : en
Pages : 218

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Book Description
Contrast agents for medical ultrasound imaging is a field of growing interest. A large amount of literature has been published on the medical applications of such contrast agents. However, there is no textbook giving a broad overview of the physics and acoustics of the agents. This monograph aims to fill this gap. The book is written by a physicist, from a physics point of view, and it tries to draw links from the physics and acoustics to the medical imaging methods, but medical applications are mainly included for background information. The book consists of nine chapters. The first three chapters give a broad overview of the acoustic theory for bubble-sound interaction, both linear and nonlinear. Most contrast agents are stabilized in a shell, and this shell can have a strong influence on the interaction between the bubbles and the ultrasound. The effect of the shell is given special attention, as this is not easily found in other bubble literature. The following chapters, 4, 5, 6, and 7, describe experimental and theoretical methods used to characterize the acoustic properties of the agents, and results of studies on some agents. Chapter 8 shows how the theory and the experimental results can be combined and used to model various phenomena by means of computer simulations. The main purpose of the simulations is to get insight into the mechanisms behind the described phenomena, not to get accurate predictions and values. The book is aimed at both newcomers into the field, as well as those who are more experienced but want better insight into the acoustics of the contrast bubbles.

Author: Peter Johan Anton Frinking
Publisher:
ISBN: 9789090132785
Category :
Languages : en
Pages : 149

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Author: Gaio Paradossi
Publisher: Springer Science & Business Media
ISBN: 8847014948
Category : Technology & Engineering
Languages : en
Pages : 199

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Recent advancements in nano/micro materials and related characterization approaches allow the design of a new type of ultrasound contrast agents (UCAs) with enhanced multifunctional behaviour. This is chance is also supported by the recent achievements in modelling and signal processing. This book provides the state of art of the research activity of two successful European projects, TAMIRUT and SIGHT, addressing an integrated system, encompassing the contrast agent, the hardware equipment and the processing strategies, as a key tool for a combined diagnostic and therapeutic approaches (theranostics) in medical ultrasound. The work provides a highlight of the state of art in the research of novel ultrasound contrast agents (UCAs). Main progresses on the multifunctional aspects of next-generation UCAs concern targeting and drug release properties, perfusion and biointerface behaviour, ultrasound scattering performance, signal processing, electronic equipment.

Author: Pankaj Jain
Publisher: ProQuest
ISBN: 9780542817083
Category : Microbubbles
Languages : en
Pages :

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Ultrasound contrast agents are micron size bubbles used for medical purposes such as diagnostic ultrasound imaging and targeted drug delivery. These bubbles are encapsulated with a shell and have a sparingly soluble gas inside to prevent them from premature dissolution. When these bubbles are excited by the ultrasound they scatter and absorb energy from the sound field, thus leading to the attenuation of the ultrasound signal. In this thesis, we have developed a viscous and a viscoelastic model for the shell. Attenuation measured in vitro is compared with model predictions to obtain the characteristic model parameters (surface tension, shell elasticity, dilatational viscosity) for commercially available contrast agents. The viscous model predicts unusually high values of surface tension which motivated the viscoelastic model. We have also used both models to predict the scattered response of microbubbles. (Abstract shortened by UMI.).

Author: Hua Lee
Publisher: Springer Science & Business Media
ISBN: 0306471086
Category : Science
Languages : en
Pages : 405

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Book Description
The International Symposium of Acoustical Imaging has been widely recognized as the premier forum for presentations of advanced research results in both theoretical and experimental development. Held regularly since 1968, the symposium brings together th leading international researchers in the area of acoustical imaging. The 24 meeting is the third time Santa Barbara hosted this international conference and it is the first time the meeting was held on the campus of the University of California, Santa Barbara. As many regular participants noticed over the years, this symposium has grown significantly in size due to the quality of the presentations as well as the organization itself. A few years ago multiple and poster sessions were introduced in order to accommodate this growth. In addition, the length of the presentations was shortened so more papers could be included in the sessions. During recent meetings there were discussions regarding the possibility of returning to the wonderful years when the symposium was organized in one single session with sufficient time to allow for in-depth presentation as well as discussions of each paper. And the size of the meeting was small enough that people were able to engage in serious technical interactions and all attendees would fit into one photograph. In light of the constraints of the limited budget with respect to the escalating costs it was not considered feasible.

Author: Riccardo Lencioni
Publisher: Springer Science & Business Media
ISBN: 8847004764
Category : Medical
Languages : en
Pages : 252

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Book Description
This book provides an up-to-date overview on the clinical value of contrast agents in ultrasound. The volume moves from a background section on technique and methodology to the main sections on the clinical application of contrast ultrasound in the liver and in vascular diseases. A final section discusses results and prospects of contrast ultrasound modality in the other fields.

Author: Yanjun Gong
Publisher:
ISBN:
Category :
Languages : en
Pages : 294

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Book Description
Abstract: Lipid-coated microbubbles, which have been widely used in diagnostic ultrasound as contrast agents, also show promising applications in medical therapy. The knowledge of acoustic behaviors and shell properties with respect to Ultrasound Contrast Agents (UCA) microbubbles can greatly enhance and extend their clinical applications. A polydimethylsiloxane (PDMS-based microfluidic flow-focusing device was fabricated to produce lipid-coated microbubbles with narrow size distribution and controllable mean diameters (3-12um). These monodisperse microbubbles show unique acoustic properties compared with commercial UCA microbubbles with wide size distribution, which makes it possible to investigate the relationship between microbubble size and attenuation coefficient, resonance frequency, or backscattering experimentally. Our studies show that monodisperse microbubbles can be tailored for optimal contrast enhancement in ultrasound imaging. By using an ultrasound spectroscopy method, the frequency-dependent attenuation coefficient for monodisperse microbubbles and polydisperse microbubbles were measured and compared. The results showed that decreasing the width of the microbubble size distribution would lead to a reduction in the bandwidth, and an increase in the magnitude of the attenuation spectrum. The resonance frequency determined by the attenuation coefficient peak was inversely proportional to the mean diameter of the monodisperse microbubble suspension. These conclusions corroborated the theoretical predications. The dependence of resonance frequency on acoustic pressure and lipid composition have also been examined and compared with theoretical calculations. The results demonstrated that the lipid shell of microbubbles behaviors nonlinearly, even at low pressure, which results in a decrease of resonance frequency as incident pressure was increased, approaching the resonance frequency of uncoated bubbles. Moreover, the length of the lipid hydrocarbon chain impacts the dependences of shell stiffness, attenuation coefficient, and resonance frequency on the excitation pressure. The frequency-dependent backscattering coefficients for monodisperse microbubbles have been investigated using a broadband pulses technique over different sizes, concentrations and pressures. The experimental results showed the same size-dependent resonance peaks as attenuation coefficient. It demonstrated that increasing the acoustic pressure caused a frequency shift of resonance peak, but no significant changes on magnitude. A linear dependence on microbubble concentration for backscatter coefficient was confirmed. In addition, the pressure-dependent backscattering coefficients at 2.25 MHz were studied. It is interesting to note that with the increase of incident pressure, the change of backscattering coefficients values, increase or decrease, were strongly dependent on the mean size of microbubbles.

Author: Chao Sun
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Alicia Clark
Publisher:
ISBN:
Category :
Languages : en
Pages : 115

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Book Description
Ultrasound contrast agents are micron-sized bubbles that are used for ultrasound imaging enhancement and that can potentially be used for targeted drug delivery applications. One strategy to manipulate them inside the cardiovascular system is to use the Bjerknes force, caused by the phase difference between a transmitted ultrasound pressure wave and the microbubble volume oscillations induced by the pressure wave. Although the mechanism causing this force is well established, the balance between ultrasound-induced forces and hydrodynamic forces is poorly understood when the microbubbles are immersed in physiologically-realistic Reynolds and Womersley number flows. In this thesis, experiments were conducted in a cylindrical tube under steady and pulsatile flows over a range of Reynolds and Womersley numbers relevant to drug delivery in the systemic circulation. Two experimental setups were developed: one in which the microbubbles were imaged using a clinical ultrasound imaging system, and a second in which they were imaged by high-speed video using a long distance microscope. In the ultrasound experimental setup, a commercial L15-7io transducer was used to image microbubbles in quiescent, steady, and pulsatile flows. These experiments were extended in the optical experimental setup to explore higher Reynolds numbers. In the optical experiments, individual microbubble trajectories were captured at high magnification and high temporal resolution to determine the relationship between acoustic and hydrodynamic forces. The relative scaling of these forces was computed for different acoustic pressure amplitudes and pulse repetition frequencies. The Bjerknes force scaled linearly with pulse repetition frequency and quadratically with acoustic amplitude. The displacement of the microbubbles due to the ultrasound decreased with increasing Reynolds number suggesting a threshold for clinical applications due to the residence time of microbubbles in the ultrasound beam.