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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Title Study of: Transthoracic propagation of ultrasound.
Author Crawford HD.
Journal Rep Okla State Univ Sch Elect Eng
Volume
Year 1961-1963
Abstract No abstract available. Terminal report.


Title Study on the effects of ultrasound on the nervous system (III). Effects of ultrasound on the sciatic nerve.
Author Okumura T
Journal Med J Osaka Univ
Volume
Year 1960
Abstract No abstract available.


Title Study on ultrasonic properties of human gallstone in vitro. [Article in Chinese.]
Author Ruo F.
Journal Chin J Ultrasound Med
Volume
Year 1992
Abstract The acoustic parameters, such as sound speed, attenuation coefficient, etc., for 25 human gallstones in vitro were measured at frequency of 1 MHz by using the pulse insertion substitution method. The obtained results show that the speed is widely dispersed from 1688.8m/s to 2414.5 m/s, and the value of speed, Cs(m/s), tends to decrease with the increase of the gallstone thickness, D(mm), which can be described by the regression equation Cs=3382.2 D(exp)(-0.30) m/s (correlation coefficient r=0.92). The value of sound attenuation of gallstones was found to be very high, ranging from 21.6 dB/cm to 107.8 dB/cm. No distinct difference in acoustic parameters was observed for different constituent categories of the gallstones. The significance of these findings has been discussed along with the application of ultrasound in clinical medicine.


Title Superresolution of ultrasound images using the first and second harmonic signal.
Author Taxt T, Jirik R.
Journal IEEE Trans UFFC
Volume
Year 2004
Abstract This paper presents a new method of blind two-dimensional (2-D) homomorphic deconvolution and speckle reduction applied to medical ultrasound images. The deconvolution technique is based on an improved 2-D phase unwrapping scheme for pulse estimation. The input images are decomposed into minimum-phase and allpass components. The 2-D phase unwrapping is applied only to the allpass component. The 2-D phase of the minimum-phase component is derived by a Hilbert transform. The accuracy of 2-D phase unwrapping is also improved by processing small (16/spl times/16 pixels) overlapping subimages separately. This takes the spatial variance of the ultrasound pulse into account. The deconvolution algorithm is applied separately to the first and second harmonic images, producing much sharper images of approximately the same resolution and different speckle patterns. Speckle reduction is made by adding the envelope images of the deconvolved first and second harmonic images. Neither the spatial resolution nor the frame rate decreases, as the common compounding speckle reduction techniques do. The method is tested on sequences of clinical ultrasound images, resulting in high-resolution ultrasound images with reduced speckle noise.


Title Superthreshold behavior and threshold estimates of ultrasound-induced lung hemorrhage in adult rats: Role of beamwidth.
Author O'Brien WD Jr, Simpson DG, Frizzell LA, Zachary JF.
Journal IEEE Trans UFFC
Volume
Year 2001
Abstract It is well documented that ultrasound-induced lung hemorrhage can occur in mice, rats, rabbits, pigs, and monkeys. The objective of this study was to assess the role of the ultrasound beamwidth (beam diameter incident on the lung surface) on lesion threshold and size. A total of 144 rats were randomly exposed to pulsed ultrasound at three exposure levels and four beamwidths (12 rats per group). The three in situ peak rarefactional pressures were about 5, 7.5, and 10 MPa. The four 19-mm-diameter focused transducers had measured pulse-echo -6-dB focal beamwidths of 470 ?m (2.8 MHz; f/1), 930 ?m (2.8 MHz; f/2), 310 ?m (5.6 MHz; f/1), and 510 ?m (5.6 MHz; f/2). Exposure durations were 10 s, pulse repetition frequencies were 1 kHz, and pulse durations were 1.3 ?s (2.8 MHz; f/1), 1.2 ?s (2.8 MHz; f/2), 0.8 ?s (5.6 MHz; f/1) and 1.1 ?s (5.6 MHz; f/2). The lesion surface area and depth were measured for each rat as well as the percentage of rats with lesions per group. Logistic regression analysis and Gaussian-Tobit analysis methods were used to analyze the data. The effects of in situ peak rarefactional pressure and beamwidth were highly significant, but ultrasonic frequency was not significant. In addition, the estimated interaction between in situ peak rarefactional pressure and beamwidth was positive and highly significant. The ultrasound beamwidth incident on the lung surface was shown to strongly affect the percentage and size of ultrasound-induced lung hemorrhage lesions. Even though ultrasonic frequency was an experimental variable, it was not shown to affect the lesion percentage or size.


Title Superthreshold behavior and threshold estimation in ultrasound-induced lung hemorrhage in pigs: Role of age dependency.
Author O'Brien WD Jr, Simpson DG, Ho MH, Miller RJ, Frizzell LA, Zachary JF.
Journal IEEE Trans UFFC
Volume
Year 2003
Abstract Age-dependent threshold and superthreshold behavior of ultrasound-induced lung hemorrhage were investigated with 116 2.1 /spl plusmn/ 0.3-kg neonate crossbred pigs (4.9 /spl plusmn/ 1.6 days old), 103 10 /spl plusmn/ 1.1-kg crossbred pigs (39 /spl plusmn/ 5 days old), and 104 20 /spl plusmn/ 1.2-kg crossbred pigs (58 /spl plusmn/ 5 days old). Exposure conditions were: 3.1 MHz, 10-s exposure duration, 1-kHz pulse repetition frequency (PRF), and 1.2-/spl mu/s pulse duration. The in situ (at the pleural surface) peak rarefactional pressure ranged between 2.2 and 10.4 MPa with either eight or nine acoustic pressure groups for each of the three pig ages (12 pigs/exposure group) plus sham exposed pigs. There were no lesions in the shams. Pigs were exposed bilaterally with the order of exposure (left then right lung, or right then left lung) and acoustic pressure both randomized. Pig age was not randomized. Individuals involved in animal handling, exposure, and lesion scoring were blinded to the exposure condition. Logistic regression analysis was used to examine the dependence of the lesion incidence rates on in situ peak rarefactional pressure, left versus right lung exposure, order of exposure (first versus second), and age in three age groups. Likewise, lesion depth and lesion root surface area were analyzed using Gaussian tobit regression analysis. A significant threshold effect on lesion occurrence was observed as a function of age; younger pigs were less susceptible to lung damage given equivalent in situ exposure. Overall, the oldest pigs had a significantly lower threshold (2.87 /spl plusmn/ 0.29 MPa) than middle-aged pigs (5.83 /spl plusmn/ 0.52 MPa). The oldest pigs also had a lower threshold than neonate pigs (3.60 /spl plusmn/ 0.44 MPa). Also, an unexpected result was observed. The ultrasound exposures were bilateral, and the threshold results reported above were based on the lung that was first exposed. After the first lung was exposed, the pig was turned over and the other lung was exposed to the same acoustic pressure. There was a significant decrease (greater than the confidence limits) in occurrence thresholds: 3.60 to 2.68, 5.83 to 2.97, and 2.87 to 1.16 MPa for neonates, middle-aged, and oldest pigs, respectively, in the second lung exposed. Thus, a subtle effect in lung physiology resulted in a major effect on lesion thresholds.


Title Superthreshold behavior and threshold estimation of ultrasound-induced lung hemorrhage in adult mice and rats.
Author Zachary JF, Sempsrott JM, Frizzell LA, Simpson DG, O'Brien WD Jr.
Journal IEEE Trans UFFC
Volume
Year 2001
Abstract Threshold estimates and superthreshold behaviors for US-induced lung hemorrhage were investigated as a function of species (adult mice and rats) and US frequency (2.8 and 5.6 MHz). A total of 151 6-to-7-week-old female ICR mice and 160 10-to-11-week-old female Sprague-Dawley rats were randomly divided into two US frequency groups, and further randomly divided into seven or eight US peak rarefactional pressure groups. Each group consisted of about 10 animals. Animals were exposed to pulsed US at either 2.8-MHz center frequency (1-kHz PRF, 1.42 µs pulse duration) or 5.6-MHz center frequency (1-kHz PRF, 1.17 µs pulse duration) for a duration of 10 seconds. The in situ (at the pleural surface) peak rarefactional pressure levels ranged between 2.5 and 10.5 MPa for mice and between 2.3 and 11.3 MPa for rats. The mechanical index (MI) ranged between 1.4 and 6.3 at 2.8 MHz for mice and between 1.1 and 3.1 at 5.6 MHz for rats. The lesion surface area and depth were measured for each animal as well as the percentage of animals with lesions per group. The characteristics of the lesions produced in mice and rats were similar to those described in previous studies, suggesting a common pathogenesis in the initiation and propagation of the lesions at the gross and microscopic levels. The percentage of animals with lesions showed no statistical differences between species or between US frequencies. These findings suggest that mice and rats are similar in sensitivity to US-induced lung damage and that the occurrence of lung damage is independent of frequency. Lesion depth and surface area also showed no statistically significant differences between US frequencies for mice and rats. However, there was a significant difference between species for lesion area and a suggestive difference between species for lesion depth. The superthreshold behavior of lesion area and depth showed that rat lung had more damage than mouse lung, and the threshold estimates shelved a weak, or lack of, frequency dependency, suggesting that the MI is not consistent with the observed findings.


Title Superthreshold behavior of ultrasound-induced lung hemorrhage in adult mice and rats: Role of pulse repetition frequency and exposure duration.
Author O'Brien WD Jr, Frizzel LA, Schaeffer DJ, Zachary JF.
Journal Ultrasound Med Biol
Volume
Year 2001
Abstract Superthreshold behavior for ultrasound-induced lung hemorrhage was investigated in adult mice and rats at an ultrasound center frequency of 2.8 MHz to assess the role of pulse repetition frequency and exposure duration. One hundred fifty, 6–7-week-old female ICR mice and 150 10–11-week-old female Sprague-Dawley rats were each divided into 15 exposure groups (10 animals per group) for a 3 × 5 factorial design (3 exposure durations of 5, 10, and 20 s and 5 pulse repetition frequencies of 25, 50, 100, 250, and 500 Hz). The in situ (at the pleural surface) peak rarefactional pressure of 12.3 MPa and the pulse duration of 1.42 μs were the same for all ultrasonically-exposed animals. In addition, 15 sham exposed mice and 15 sham exposed rats were included into both studies. In each study of 165 animals, the exposure conditions were randomized. The lesion depth and surface area were measured for each animal, as well as the percentage of animals with lesions per group. The characteristics of the lesions produced in mice and rats were similar to those described in studies by our research group and others, suggesting a common pathogenesis for the initiation and propagation of the lesions at the gross and microscopic levels. The proportion of lesions in both species was related statistically to pulse repetition frequency (PRF) and exposure duration (ED), with the exception that PRF in rats was not quite significant; the PRF × ED interaction (number of pulses) for lesion production was not significant for either species. The PRF, but not ED, significantly affected lesion depth in both species; the PRF × ED interaction for depth was not significant for either species. Both PRF and ED significantly affected lesion surface area in mice, while neither affected area in rats; the PRF × ED interaction for surface area was not significant for either species.


Title Superthreshold behavior of ultrasound-induced lung hemorrhage in adult rats.
Author O'Brien WD JR, Simpson DG, Frizzell LA, Zachary JF.
Journal J Ultrasound Med
Volume
Year 2005
Abstract Objective. The purpose of this study was to augment and reevaluate the ultrasound-induced lung hemorrhage findings of a previous 5 x 3 factorial design study (Ultrasound Med Biol 2001; 27:267?277) that evaluated the role of pulse repetition frequency (PRF: 25, 50, 100, 250, and 500 Hz) and exposure duration (ED; 5, 10, and 20 s) on ultrasound-induced lung hemorrhage at an in situ (at the pleural surface) peak rarefactional pressure [pr(in situ)] of 12.3 MPa; only PRF was found to be significant. However, saturation (response plateau) due to the high pr(in situ) might have skewed the results. In this follow-up 3 x 3 factorial design study, a wider range of PRFs and EDs were used at a lower pr(in situ). Methods. Sprague Dawley rats (n = 198) were divided into 18 ultrasonically exposed groups (10 rats per group) and 6 sham groups (3 per group). The 3 x 3 factorial design study (PRF: 17, 170, and 1700 Hz; ED: 5, 31.6, and 200 s) was conducted at 2 frequencies (2.8 and 5.6 MHz). The pr(in situ) was 6.1 MPa. Logistic regression analysis evaluated lesion occurrence, and Gaussian tobit analysis evaluated lesion depth and surface area. Results. Frequency did not have a significant effect, so the analysis combined results for the 2 frequencies. For lesion occurrence and sizes, the main effects for PRF and ED were not significant. The interaction term was highly significant, indicating a strong dependence of lesion occurrence and size on the total number of pulses (PRF x ED). Conclusions. The results of both studies are consistent with the hypothesis that the total number of pulses is an important factor in the genesis of ultrasound-induced lung hemorrhage.


Title Superthreshold behavior of ultrasound-induced lung hemorrhage in adult rats: Role of pulse repetition frequency and pulse duration.
Author O'Brien WD Jr., Simpson DG, Frizzell LA, Zachary JF.
Journal J Ultrasound Med
Volume
Year 2006
Abstract Objective. The purpose of this study was to enhance the findings of an earlier ultrasound-induced lung hemorrhage study ( Ultrasound Med Biol 2003; 29:1625?1634) that estimated pressure thresholds as a function of pulse duration (PD: 1.3, 4.4, 8.2, and 11.6 ?s; 2.8 MHz; 10-s exposure duration [ED]; 1-kHz pulse repetition frequency [PRF]). In this study, the roles of PRF and PD were evaluated at 5.9 MPa, the peak rarefactional pressure threshold near that of the ED50 estimate previously determined. Methods. A 4 x 4 factorial design study (PRF: 50, 170, 500, and 1700 Hz; PD: 1.3, 4.4, 8.2, and 11.6 ?s) was conducted (2.8 MHz; 10-s ED). Sprague Dawley rats (n = 175) were divided into 16 exposure groups (10 rats per group) and 1 sham group (15 rats); no lesions were produced in the sham group. Logistic regression analysis evaluated significance of effects for lesion occurrence, and Gaussian tobit analysis evaluated significance for lesion depth and surface area. Results. For lesion occurrence and sizes, the main effect of PRF was not significant. The interaction term, PRF x PD, was highly significant, indicating a strong positive dependence of lesion occurrence on the duty factor. The main effect of PD was almost significant (P = .052) and thus was included in the analysis model for a better fit. Conclusions. Compared with the findings from a PRF x ED factorial study ( J Ultrasound Med 2005; 24:339?348), a function that considers PRF, PD, and ED might yield a sensitive indicator for consideration of a modified mechanical index, at least for the lung.


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