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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William D. O'Brien, Jr. publications:

Michael L. Oelze publications:

Aiguo Han publications:

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Your search for ultrasound produced 3296 results.

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Title Application of l1 regularization for high-quality reconstruction of ultrasound tomography
Author Tran-Duc T, Linh-Trung N, Oelze ML, Do MN.
Journal Proc IFMBE
Volume
Year 2013
Abstract Ultrasound tomography based on inverse scattering has the capability to resolve structures which are smaller than the wavelength of the incident wave, as opposed to conventional ultrasound imaging using echo method. Some material properties such as sound contrast are very useful to detect small objects. Born Iterative Method (BIM) based on first-order Born approximation has been introduced as an efficient diffraction tomography approach. However, this method has a high complexity because it has to solve large iterative forward and inverse problems. In this paper, we propose to replace Tikhonov regularization by l1-regularized least squares problem (LSP) in solving the inverse problem in BIM. As a result, the quality of reconstruction is improved and the complexity is reduced.


Title Application of liposomes to sonoporation.
Author Wu J, Chen D, Pepe J, Himberg BE, Ricn M.
Journal Ultrasound Med Biol
Volume
Year 2006
Abstract A method to prepare liposomes is presented. Liposomes made in our laboratory were characterized acoustically and optically. The phase velocity and attenuation of liposomes in suspension (concentration = 10(9)/mL) were measured, ranging from 2 to 14 MHz, using ultrasound spectroscopy. Anti-rabbit IgG conjugated with Alexafluor 647 was delivered into Jurkat cells in suspension, using the liposomes, by 10 % duty cycle ultrasound tonebursts of 2.2 MHz (the in situ spatial peak-pressure amplitude = 80 W/cm2) with an efficiency of 13 %. It has been experimentally shown that liposomes may be an alternative stable agent to Optison for delivering macromolecules into cells.


Title Application of neural nets to ultrasound tissue characterization.
Author Ostrem JS, Valdes AD, Edmonds PD.
Journal Ultrason Imaging
Volume
Year 1991
Abstract No abstract available.


Title Application of phase-insensitive detection and frequency-dependent measurements to computed ultrasonic attenuation tomography.
Author Klepper JR, Brandenburger GH, Mimbs JW, Sobel BE, Miller JG.
Journal IEEE Trans Biomed Eng
Volume
Year 1981
Abstract Physical principles underlying the application of the techniques of computed tomography to quantitative imaging of the ultrasonic attenuation within soft tissue specimens are explored. From a phenomenological model of the propagation of ultrasound through inhomogenous media, appropriate methods are reviewed that provide attenuation measurements consistent with the imaging equations of computed tomography. Specifically, the use of a phase-insensitive acoustoelectric receiving transducer is demonstrated to eliminate phase cancellation errors. Attenuation reconstructions based on the slope of the attenuation coefficient as a function of frequency are shown to reduce image artifacts arising from reflection and refraction. A new technique is described to compensate for the frequency dependence of the transmitter directivity pattern in the computation of the slope. Reconstructed images of excised hearts are used to illustrate these techniques. The used of ultrasonic computed tomography to identify tissue pathology in vitro is demonstrated using myocardial infarction in the dog as a model. Results of attenuation and time-of-flight reconstructions are compared, with both methods demonstrated to be capable of differentiating normal myocardium from infarct. The consequences of anisotropy, i.e., the dependence of the attenuation on the direction of ultrasonic propagation, are discussed in the context of computed tomographic imaging.


Title Application of stochastic analysis to ultrasonic echoes--estimation of attenuation and tissue heterogeneity from peaks of echo envelope.
Author He P, Greenleaf JF.
Journal J Acoust Soc Am
Volume
Year 1986
Abstract A study of the statistics of ultrasound speckle indicates that the noise-to-signal ratio (NSR) of the echo envelope peaks (EEP) in.a B scan is monotonically related to the variance of the mean power of the backscattered echoes. If it is assumed that the.backscattered echoes all have the same mean power, the NSR of the EEP's in a B scan will be expected to reach a theoretical.minimum value NSR0 (0.40 approximately 0.42). In practical situations, the variance of the mean power of the echoes is.increased due to the presence of both attenuation (including beam spreading) and the spatial variation in the backscattering cross.section (BCS) of the tissue. Accordingly, the measured value of the NSR of the EEP's is expected to be greater than the NSR0..In principle, the effects of beam pattern and the attenuation can be compensated for by system calibration and a depth-related.gain function, respectively. The attenuation coefficient of the tissue may then be obtained by adjusting the gain function to.minimize the NSR of the EEP's. Due to the random nature of the heterogeneity of diseased tissue, the effect of the variation in.the BCS, however, cannot be compensated for by the depth-related gain function. Therefore, the minimum value of the NSR.indicates the spatial variation in the BCS and may finally correlate to the disease state of the tissue. .


Title Application of the sinc basis moment method to the reconstruction of infinite circular cylinders.
Author Cavicchi TJ, Johnson SA, O'Brien WD Jr.
Journal IEEE Trans UFFC
Volume
Year 1988
Abstract A solution of the ultrasonic scattering and inverse scattering problem has been obtained by solving the inhomogeneous Helmholtz wave equation via the sinc basis moment method. In this numerical study the algorithm of Johnson and Tracy has been applied to the reconstruction of an infinite circular cylinder that is subject to an incident cylindrical wave of ultrasound and is surrounded by a homogeneous coupling medium. For weak scattering cylinders, successful reconstruction have been obtained using the known exact solution for the scattered field as the input data for the algorithm. Five-percent noise added to the scattered field values does not significantly affect performance. A detailed discussion of sampling requirements for this algorithm is presented, and the threshold derived correlates well with results of a numerical study of variation of the sampling density. Effects of varying object contrast, object size, grid size, sampling density, and method of iteration are investigated. Optimization of computation is described, for slowness is the most serious limitation of the algorithm. Use of either the discrete scattered field equations or the exact Bessel function series solution yielded identical results, verifying the validity of the sinc function expansions.


Title Application of three scattering models to characterization of solid tumors in mice.
Author Oelze ML, O'Brien WD Jr.
Journal Ultrason Imaging
Volume
Year 2006
Abstract Two mouse models of mammary cancer (a carcinoma and sarcoma) were examined using quantitative ultrasound (QUS) and three models for ultrasound backscattering. The first model that was examined was the spherical Gaussian model (SGM). The second model was the fluid-filled sphere model (FFSM) and was hypothesized to model scattering from cell nuclei with the cell cytoplasm acting as background. The third model, called the new cell model (NCM), was constructed to model backscattering from cell nuclei and cytoskeleton. The average scatterer diameters (ASDs) were estimated from regions-of-interest (ROIs) inside the tumors using all three models and then compared. The ultrasound analysis bandwidth used in the study was 16 to 27 MHz. QUS images of the tumors utilizing the ASD estimates from the three models were constructed. The ASDs were 30.3 +/- 3.06 microm and 25.2 +/- 4.01 microm with the SGM, 47.3 +/- 7.99 microm and 47.7 +/- 7.01 microm with the FFSM and 41.2 +/- 1.39 microm and 34.4 +/- 5.95 microm with the NCM for the carcinoma and sarcoma, respectively, statistically significant differences between the ASD estimates from the carcinomas and sarcomas were observed using the SGM and NCM but not with the FFSM.


Title Application of ultrasound in medicine.
Author Lele PP.
Journal N Engl J Med
Volume
Year 1972
Abstract No abstract available.


Title Application of ultrasound.
Author Baum G.
Journal JAMA
Volume
Year 1974
Abstract No abstract available.


Title Applications of a simple theory of the acoustic motion of fibrous.networks in viscous media.
Author McQueen D.
Journal Ultrasonics
Volume
Year 1977
Abstract The rupture of blood capillaries in the spinal chords of rats by pulsed ultrasound and the motion of fibrils in the corneal stroma are analysed in detail in terms of a simple theory of wave propagation in a fibrous network permeated by a viscous.medium. The advantages of inelastic light scattering experiments in connection with studies of ultrasound are emphasized.


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