Bioacoustics Research Lab
University of Illinois at Urbana-Champaign | Department of Electrical and Computer Engineering | Department of Bioengineering
Department of Statistics | Coordinated Science Laboratory | Beckman Institute | Food Science and Human Nutrition | Division of Nutritional Sciences | College of Engineering
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Your search for ultrasound produced 3296 results.

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Title Microbubble administration accelerates clot lysis during continuous 2-MHz ultrasound monitoring in stroke patients treated with intravenous tissue plasminogen activator.
Author Molina CA, Ribo M, Ruberia M, Montaner J, Santamarina E, Delgado-Mederos R, Arenillas JF, Huertas R, Purroy F, Delgado P, Alvarez-Sabin J.
Journal Stroke
Volume
Year 2006
Abstract Matrigel, a basement membrane extract, has been extensively used in in vivo angiogenesis. Contrast ultrasound imaging (CUI) of implanted Matrigel plugs with (+bFGF) and without basic fibroblast growth factor (−bFGF) was performed 7 and 14 d after implantation, followed by histologic analysis. Statistically significant differences between +bFGF and −bFGF plugs were apparent at d 7 in both plug size and contrast enhancement (both p < 0.05). Histopathology revealed differences in microvessel density (MVD) between +bFGF and −bFGF at d 7 and d 14. A significant correlation between MVD and both power Doppler contrast-enhanced area (r = 0.65, p < 0.05) and fraction of plug enhanced (r = 0.59, p < 0.05) was present. CUI of Matrigel plugs was shown to be a robust method for distinguishing between two different angiogenic states. Ultrasound measurements of blood flow in the plugs correlated with MVD, a histologic technique used to quantify tumor angiogenesis. (E-mail: smstieger@ucdavis.edu) Key Words: Contrast ultrasound imaging; Angiogenesis; Matrigel; Tumor; Power Doppler; Rat


Title Microbubbles in ultrasound-triggered drug and gene delivery.
Author Hernot S, Klibanov AL.
Journal Adv Drug Deliv Rev
Volume
Year 2008
Abstract Ultrasound contrast agents, in the form of gas-filled microbubbles, are becoming popular in perfusion monitoring; they are employed as molecular imaging agents. Microbubbles are manufactured from biocompatible materials, they can be injected intravenously, and some are approved for clinical use. Microbubbles can be destroyed by ultrasound irradiation. This destruction phenomenon can be applied to targeted drug delivery and enhancement of drug action. The ultrasonic field can be focused at the target tissues and organs; thus, selectivity of the treatment can be improved, reducing undesirable side effects. Microbubbles enhance ultrasound energy deposition in the tissues and serve as cavitation nuclei, increasing intracellular drug delivery. DNA delivery and successful tissue transfection are observed in the areas of the body where ultrasound is applied after intravascular administration of microbubbles and plasmid DNA. Accelerated blood clot dissolution in the areas of insonation by cooperative action of thrombolytic agents and microbubbles is demonstrated in several clinical trials.


Title Microbubbles in ultrasound-triggered drug and gene delivery.
Author Hernot S, Klibanov AL.
Journal Adv Drug Deliv Rev
Volume
Year 2008
Abstract Ultrasound contrast agents, in the form of gas-filled microbubbles, are becoming popular in perfusion monitoring; they are employed as molecular imaging agents. Microbubbles are manufactured from biocompatible materials, they can be injected intravenously, and some are approved for clinical use. Microbubbles can be destroyed by ultrasound irradiation. This destruction phenomenon can be applied to targeted drug delivery and enhancement of drug action. The ultrasonic field can be focused at the target tissues and organs; thus, selectivity of the treatment can be improved, reducing undesirable side effects. Microbubbles enhance ultrasound energy deposition in the tissues and serve as cavitation nuclei, increasing intracellular drug delivery. DNA delivery and successful tissue transfection are observed in the areas of the body where ultrasound is applied after intravascular administration of microbubbles and plasmid DNA. Accelerated blood clot dissolution in the areas of insonation by cooperative action of thrombolytic agents and microbubbles is demonstrated in several clinical trials.


Title Microbubbles induce renal hemorrhage when exposed to diagnostic ultrasound in anesthetized rats.
Author Wible JH Jr,Galen KP,Wojdyla JK,Hughes MS,Klibanov AL,Brandenburger GH.
Journal Ultrasound Med Biol
Volume
Year 2002
Abstract The generation of ultrasound (US) bioeffects using a clinical imaging system is controversial. We tested the hypothesis that the presence of microbubbles in the US field of a medical imager induces biologic effects. Both kidneys of anesthetized rats were insonified for 5 min using a medical imaging system after the administration of microbubbles. One kidney was insonified using a continuous mode (30 Hz) and the opposite kidney was insonified using an intermittent (1 Hz) technique. The microbubbles were exposed to three different transducer frequencies and four transducer output powers. After insonification, the animals were euthanized, the kidneys were removed and their gross appearance scored under “blinded” conditions using a defined scale. After the administration of microbubbles, US imaging of the kidney caused hemorrhage in the renal tissue. The severity and area of hemorrhage increased with an increase in the transducer power and a decrease in the transducer frequency. Intermittent insonification in the presence of microbubbles produced a greater degree of renal hemorrhage than continuous imaging techniques. (E-mail: james.wible@tycohealthcare.com) Keywords: Microbubbles; Ultrasound contrast agents; Bioeffects; Hemorrhage; Transducer frequency; Output power


Title Microcalifications as elastic scatterers under ultrasound.
Author Anderson ME, Soo MSC, Trahey GE.
Journal IEEE Trans UFFC
Volume
Year 1998
Abstract One of the fundamental limitations of medical ultrasound in the imaging of the breast is the inability of current practice to reliably visualize microcalcifications in the size range of clinical interest. Microcalcifications (MCs) are small crystals of calcium phosphates that form in human tissue through a number of mechanisms. The size, morphology, and distribution of MCs are important indicators in the mammographic screening for and diagnosis of various carcinomas in the breast. We are investigating the imaging of MCs under ultrasound in the interest of extending the utility of medical ultrasound in the breast clinic. We present an analysis of the acoustic properties of MCs modeled as elastic spheres based on the Faran model that considers the predicted complex spectra and spatial coherence of echoes from MCs. We have found the predictions of the model to be similar to ultrasound echoes form suspected MCs in vivo. We also present breast phase aberration estimates and spatial and frequency compounding results based on the echoes from these targets.


Title Micromachined high frequency ferroelectric sonar transducers.
Author Bernstein JJ, Finberg SL, Houston K, Niles LC, Chen HD, Cross LE, Li KK, Udayakumar K.
Journal IEEE Trans UFFC
Volume
Year 1997
Abstract Millimeter-sized ferroelectric monomorph sonar transducers have been built using sol-gel PZT on micromachined silicon wafers. First generation transducer arrays with diaphragms varying in size from 0.2 to 2 mm were tested. Second generation 8*8 arrays have also been built and tested in water in the frequency range of 0.3 to 2 MHz. Improvements to the sol-gel process have yielded high-quality, crack-free PZT films up to 12 mu m in thickness, which leads directly to higher sensitivity and figure of merit for acoustic transducers. The longitudinal piezoelectric coefficient d(33) is 140 to 240 pC/N, measured through a double beam laser interferometer. Remanent polarization of 28 mu C/cm(^2), a coercive field of 30 kV/cm, and dielectric constant of 1400 were measured on 4- mu m thick films. Test results are presented, including frequency response, beam patterns, and sensitivity. High-resolution acoustic images have been generated using these transducers and a four-element underwater acoustic lens. Potential applications for these transducers include high-frequency imaging sonars, medical ultrasound, ultrasonic communication links, and flaw detection (NDT).


Title Micromachined two-dimensional array piezoelectrically actuated transducers.
Author Percin G, Atalar A, Degertekin FL, Khuri-Yakub TK.
Journal Appl Physics Letters
Volume
Year 1998
Abstract This letter presents micromachined two-dimensional array flextensional transducers that can be used to generate sound in air or water. Individual array elements consist of a thin piezoelectric ring and a thin, fully supported, circular membrane. We report on an optimum design for an individual array element based on finite element modeling. We manufacture the transducer in two-dimensional arrays using planar silicon micromachining and demonstrate ultrasound transmission in air at 2.85 MHz. Such an array could be combined with on-board driving and an addressing circuitry for different applications. © 1998 American Institute of Physics.


Title Microscopic effects of ultrasound on the structure of potato starch.
Author Gallant D, Degrois M, Sterling C, Guilbot A.
Journal Die Starke
Volume
Year 1972
Abstract This preliminary study has related the nature of rupture in starch grains, induced by ultrasound, to the ambient atmosphere, the concentration of the suspension, the frequency and the time of irradiation. It has been tentatively concluded that principally mechanical effects have been induced under conditions that would promote vaporous cavitation (280 KHz, 15 W/cm2). In an atmosphere of hydrogen, many deep conical pits are produced. In an atmosphere of air or oxygen, deep pitting is somewhat less pronounced than in hydrogen but injury to other parts of the surface is greater. Virtually no effect is produced in vacuo, and under carbon dioxide the effect is very weak. The extent of damage increases with time of radiation and decreases with increasing concentration of starch in the suspension. It is suggested that damage produced by ultrasound indicates a primarily radial structure of submicroscopic units in the starch grain. Explanations proposed for the effects observed must be tested in further experiments.


Title Microscopic lung alterations and reduction of respiration rate in insonated anesthetized swine.
Author Harrison GH, Eddy HA, Wang JP, Liberman FZ.
Journal Ultrasound Med Biol
Volume
Year 1995
Abstract No abstract available.


Title Microstreaming shear as a mechanism of cell death in Elodea leaves exposed to ultrasound.
Author Miller DL.
Journal Ultrasound Med Biol
Volume
Year 1985
Abstract The hypothesis that ultrasonically induced membrane damage and cell death in Elodea leaves is caused by shear stress associated with microstreaming flow generated in the vicinity of oscillating gas-filled channels between the cells is investigated. Cell death thresholds as a function of frequency seem to follow a condition of constant shear stress, with minimum thresholds near the resonance frequency of a gas-filled channel. Theoretical estimates of the shear stress generated within the cells at the ultrasonic intensity of the cel l death threshold are in order of magnitude agreement with measurements of the shear stress required for lysis of blood cells. Furthermore, the dependence of the cell death thresholds on exposure duration seems to correspond roughly with the dependence of critical shear stress for blood cells as a function of the duration of the stress. Membrane damage induced by microstreaming shear stress therefore appears to be a plausible mechanism of cell death in Elodea, and a valuable unifying concept for.consideration of bioeffects of ultrasonic cavitation.


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