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:

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Your search for ultrasound produced 3296 results.

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Title Quantitative relationship between tissue composition and scattering of ultrasound.
Author Sehgal CM.
Journal J Acoust Soc Am
Volume
Year 1993
Abstract This study establishes quantitative laws by which the magnitude of ultrasonic scatter is related to the gross chemical composition of tissues, viz., water, fat, and collagen.. Tissues are modeled as immiscible mixtures, the constituents of which are uniformly dispersed over the volume. Each component of the mixture causes the ultrasonic. velocity of the medium to fluctuate about the mean value. Such localized variations in the refractive index of a medium cause propagating sound waves to scatter. It is. proposed that the contribution of each component to the total fluctuation is in proportion to its volume fraction. The analysis shows that the scatter of ultrasound exhibits. a complex nonlinear dependence on the concentrations of the individual components. From the knowledge of sound speed of individual components, total velocity. fluctuations are determined for binary and three-component models of the tissue. Comparison on these values, with those estimated from scatter measurements, show a. close correlation between the two sets. Collagen, although present in relatively small amounts in soft tissue, contributes a significant portion of the total scatter. However,. both fat and collagen fractions must be taken into consideration to account for the major fraction of the observed scatter. In conclusion, there is a direct relationship. between tissue composition and scatter from tissues. Such dependence must also be taken into consideration, in addition to the correction function and correlation lengths. to explain backscatter or loss in a transmitted signal due to scatter from tissues.


Title Quantitative relationships between ultrasonic cavitation and effects upon amoebae at 1 MHz.
Author Coakley WT, Hampton D, Dunn F.
Journal J Acoust Soc Am
Volume
Year 1971
Abstract An amoeba, Hartmannella castellanii, which possesses many features typical of higher-order animal cells, was irradiated with 1-MHz ultrasound while suspended in ordinary growth medium and in one with increased viscosity. The ultrasonically produced cavitation was monitored and a strong correlation is found between the number of discrete cavitation events occurring and the decrease in cell numbers, on irradiating at 515 W/cm(^2) for 10 min. The growth of treated cells was also examined.


Title Quantitative study of the effects of ultrasound on biochemical systems.
Author Braginskaya FI.
Journal Sov Phys Acoust
Volume
Year 1976
Abstract Quantitative characteristics of the conversions of a number of biologically important compounds under the action of ultrasonic cavitation at 750 kHz are investigated. The investigated substances (adenine derivatives, proteins, and the TMV ribonucleoprotein) exhibit exponential dissociation and activity reduction. The values obtained by radiochemical dosimetric measurements for the initial rate and chemioacoustic efficiency of dissociation are used as a basis for postulating the relative contributions of chemical and mechanical mechanisms to the ultrasonic degradation of the investigated biochemical compounds.


Title Quantitative tissue characterization based on pulsed-echo ultrasound scans.
Author Walach E, Liu CN, Waag RC, Parker KJ.
Journal IEEE Trans Biomed Eng
Volume
Year 1986
Abstract This paper describes a novel technique for estimating ultrasonic attenuation coefficients. The technique first employs a histogram analysis to estimate the number of tissues present and then utilizes a maximum likelihood criterion to assign attenuation values, thus producing an image of attenuation. Simulated B-scan data and clinical B-scan data are used to illustrate the method. The results show that images representing an intrinsic tissue parameter can be produced when the basic model is valid.


Title Quantitative tissue motion analysis of digitized m-mode images: Gestational differences of fetal lung.
Author Adler RS, Rubin JM, Bland PH, Carson PL.
Journal Ultrasound Med Biol
Volume
Year 1990
Abstract Quantitative analysis of transmitted cardiac motion in fetal lung is evaluated by applying correlation techniques to digitized M-mode images in 21 patients, subdivided into two subgroups by gestational age: (1) 25?30 weeks (11 patients), and (11) ≥35 weeks (10 patients). The corresponding numbers of M-mode images analyzed for each group are 23 and 18, respectively. This partition is expected to reflect functionally "immature" and "mature" lungs. The estimated maximum mean radial deformation per unit epicardial excursion, left angle bracketr, is calculated from the two-time, spatially averaged correlation function obtained between diastolic and systolic M-mode lines. The collective results for each subgroup are left angle bracketr I = 0.79 ? 0.11 (sem) and left angle bracketr II = 0.62 ? 0.13 (sem). The analysis presented, albeit in a limited population, is indicative of a trend in accordance with qualitative observations of Birnholz and Farrell (1985). M-mode analysis, as indicated by Adler et al. (1989) is a potentially useful technique to quantify such tissue motion.


Title Quantitative transcutaneous measurements of blood flow in carotid artery by means of pulse and continuous wave Doppler methods.
Author Borodzinski K, Filipczynski I, Nowicki A, Powalowski T.
Journal Ultrasound Med Biol
Volume
Year 1976
Abstract No abstract available


Title Quantitative ultrasonic characterization of diffuse scatterers in the presence of structures that produce coherent echoes.
Author Luchies AC, Ghoshal G, O'Brien WD Jr, Oelze ML.
Journal IEEE Trans UFFC
Volume
Year 2012
Abstract Quantitative ultrasound (QUS) techniques that parameterize the backscattered power spectrum have demonstrated significant promise for ultrasonic tissue characterization. Some QUS parameters, such as the effective scatterer diameter (ESD), require the assumption that the examined medium contains uniform diffuse scatterers. Structures that invalidate this assumption can significantly affect the estimated QUS parameters and decrease performance when classifying disease. In this work, a method was developed to reduce the effects of echoes that invalidate the assumption of diffuse scattering. To accomplish this task, backscattered signal sections containing non-diffuse echoes were identified and removed from the QUS analysis. Parameters estimated from the generalized spectrum (GS) and the Rayleigh SNR parameter were compared for detecting data blocks with non-diffuse echoes. Simulations and experiments were used to evaluate the effectiveness of the method. Experiments consisted of estimating QUS parameters from spontaneous fibroadenomas in rats and from beef liver samples. Results indicated that the method was able to significantly reduce or eliminate the effects of nondiffuse echoes that might exist in the backscattered signal. For example, the average reduction in the relative standard deviation of ESD estimates from simulation, rat fibroadenomas, and beef liver samples were 13%, 30%, and 51%, respectively. The Rayleigh SNR parameter performed best at detecting nondiffuse echoes for the purpose of removing and reducing ESD bias and variance. The method provides a means to improve the diagnostic capabilities of QUS techniques by allowing separate analysis of diffuse and non-diffuse scatterers


Title Quantitative ultrasonic characterization of lesion composition and.remodeling in atherosclerotic rabbit aorta.
Author Wickline SA, Shepard RK, Daugherty A..Washington University School of Medicine, St Louis, Mo.
Journal Arterioscler Thromb
Volume
Year 1993
Abstract We have previously shown that high-frequency, high-resolution ultrasound can characterize the acoustic properties and.composition of fatty plaques in cholesterol-fed rabbits. To determine whether quantitative ultrasound can delineate the.regression of atherosclerotic lesions by detecting a change in their composition from fatty to fibrous types induced by.alterations in dietary regimen, we fed six New Zealand White rabbits a 2% cholesterol diet for 3 months, followed by a.standard diet for 3 additional months to promote the development of fibrous intimal lesions. Segments of aortas were excised,.and backscattered radiofrequency data were acquired from 400 to 600 independent sites in each specimen with an acoustic.microscope operated at 50 MHz. Control data were provided by measuring backscatter from adjacent portions of the aortas.devoid of lesions. Histological and immunocytochemical analyses of the fibrous intimal lesions confirmed the presence of.smooth muscle cells and abundant connective tissue with little appreciable lipid. Backscatter from normal aortic segments.(-30.7 +/- 1.0 dB) was approximately 10-fold greater than that from fibrous lesions (-42.4 +/- 1.0 dB; P < .05). We.previously reported that integrated backscatter from fatty lesions was -50.6 +/- 0.7 dB, or approximately 10-fold less than.that from fibrous lesions (P < .05). Values for integrated backscatter from the media of each tissue type were approximately.equal (-30.0 +/- 1.7 versus -30.7 +/- 1.6 versus -33.4 +/- 0.8 dB for normal versus fibrous versus fatty tissues, respectively;.P = not significant).


Title Quantitative ultrasonic tissue characterization with real-time integrated backscatter imaging in normal human subjects and in patients with dilated cardiomyopathy.
Author Vered Z, Barzilai B, Mohr GA, Thomas LJ III, Genton R, Sobel BE, Shoup TA, Melton HE, Miller JG, Perez JE.
Journal Circulation
Volume
Year 1987
Abstract We have shown previously that the physical properties of myocardium in dogs can be characterized with quantitative ultrasonic integrated backscatter and that interrogation of the tissue with ultrasound can delineate cardiac cycle-dependent changes in ultrasonic backscatter in normal tissue that disappear with ischemia and reappear with reperfusion if functional integrity is restorable. To determine whether this approach can be applied to man, we implemented an automatic gain compensation and continuous data acquisition system to characterize myocardium with quantitative ultrasonic backscatter and to detect cardiac cycle-dependent changes in real time. We developed a two-dimensional echocardiographic system with quantitative integrated backscatter imaging capabilities for use in human subjects that can automatically differentiate ultrasonic signals from blood as opposed to those obtained from tissue and adjust the slope of the gain compensation appropriately. Real-time images were formed from a continuous signal proportional to the logarithm of the integrated backscatter along each A-line. In our initial investigation, 15 normal volunteers (ages 17 to 40 years, heart rates 44 to 88 beats/min) and five patients with dilated cardiomyopathy (ages 22 to 52, heart rates 82 to 120 beats/min) were studied with conventional parasternal long-axis echocardiographic views. Diastolic-to-systolic variation of integrated backscatter in the interventricular septum and left ventricular posterior wall was seen in each of the normal subjects averaging 4.6 +/- 1.4 dB (SD) and 5.3 +/- 1.5 dB (n = 127 sites), respectively. In patients with dilated cardiomyopathy, the magnitude of this variation was either reduced or absent, averaging 0.9 +/- 0.8 dB in the interventricular septum and 1.8 +/- 1.2 dB in the left ventricular posterior wall (n = 31 sites; p < .01 for both). In eight of the 31 sites in myopathic hearts, no variation was detectable. The results obtained demonstrate that quantitative ultrasonic tissue characterization is feasible in man. Real-time integrated backscatter imagining delineates cardiac cycle-dependent changes in normal human myocardium and quantitatively differentiates between normal and myopathic myocardium. This system offers promise for the quantitative, diagnostic detection of diverse disease processes, including myocardial ischemia and responses of the tissue of reperfusion.


Title Quantitative ultrasound and the pancreas: Demonstration of early detection capability
Author Miller RJ, Han A, Gates-Tanzer LT, Erdman JW Jr, Shisler JA, Wallig MA, O'Brien WD Jr.
Journal Proc IEEE Ultrason Symp
Volume
Year 2017
Abstract Identifying real-time changes in tissues via quantitative ultrasound (QUS) approaches are clinically significant, particularly if QUS changes correspond to early detection of disease or provide early assessment of treatment success. Thus, understanding sequential steps in disease progression is key for success. Cerulein-induced inflammation of the pancreas (pancreatitis) in rodent models causes a significant release of pancreatic enzymes into blood, and it induces interstitial edema and inflammatory cell infiltration into the pancreas. This degree of pancreatitis is relatively mild: all animals survive the induction of pancreatitis that resolves itself in ∼7 days. This makes this model an excellent one for studying ultrasonic attenuation coefficient and backscatter coefficient over time. The edematous stroma, cell shrinkage and death, followed by repopulation by dedifferentiated acinar cells, has certain similarities with the morphologies of some forms of pancreatic carcinoma (PCa). The study has several unique contributions: 1) The cerulein-induced pancreatitis model can be used as a surrogate for the PCa model, particularly for detecting early responses to PCa onset/treatment. 2) Understanding the progression of acute pancreatitis per se is imperative for successful intervention and treatment, especially in the early phases of the disease, before other clinical changes are manifest. Pancreatic AC and BSC (25-55 MHz) were estimated in vivo and ex vivo at baseline (no cerulein injections) and from 2 to 168 hr after cerulein injections. Following euthanasia, the pancreas was evaluated histopathologically and biochemically. There are significant measureable early effects on both in vivo AC and BSC (and their respective ex vivo estimates) relative to baseline controls that reflect the temporal biochemical and morphological effects of cerulein. The general trend is decreased AC and BSC at early time points and then rebound increases relative to controls at later time points. The greatest AC and BSC decreases occurred at 2 hr post-cerulein injections [29% AC (in dB/cm-MHz) decrease and 34% BSC (in dB) decrease, at 25 MHz)], suggesting high likelihood for early detection of either disease onset or response to therapy using quantitative ultrasound measures.


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