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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 76 out of 330
| Title |
Correlation between Doppler vascular density and PSA response to radiation therapy in patients with localized prostate carcinoma. |
| Author |
Sehgal CM, Arger PH, Holzer AC, Krisch RE. |
| Journal |
Acad Radiol |
| Volume |
|
| Year |
2003 |
| Abstract |
Transrectal ultrasound (US) is an essential tool for the clinical management of prostate cancer. Gray-scale transrectal US is routinely used to guide biopsies and therapeutic procedures such as brachytherapy and cryotherapy. It is also frequently used to evaluate the prostate gland in patients with palpable, abnormal findings at digital rectal examination or elevated levels of prostate-specific antigen (PSA). Doppler US imaging is used increasingly to evaluate prostate cancers. Some correlation between biopsy findings and Doppler assessment of vascularity in the prostate (1-7) has been observed. However, the results to date are inconclusive, and the usefulness of Doppler technology for evaluating prostate cancer remains uncertain.
While gray-scale US and Doppler US have already been applied extensively for the diagnosis of cancer and for guiding therapeutic procedures, less attention has been given to using these methods to evaluate the response of the prostate to various therapies. An imaging marker that correlates with therapeutic efficacy could prove useful in clinical decision making related to the care of patients with prostate cancer. Currently, measurements of the serum PSA level is one of the most commonly used assays to evaluate the efficacy of therapeutic treatment. The goal of this study was to determine whether vascular measurements obtained with Doppler US before radiation therapy correlate with early PSA response following therapy. Such a correlation could be useful for predicting PSA response and for planning radiation therapy.
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| Title |
Correlation of cavitation with ultrasound enhancement of thrombolysis. |
| Author |
Datta S, Coussios CC, McAdory LE, Tan J, Porter T, De Courten-Myers G, Holland CK. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
2006 |
| Abstract |
Pulsed ultrasound, when used as an adjuvant to recombinant tissue plasminogen activator (rt-PA), has been shown to enhance thrombolysis in the laboratory as well as in clinical trials for the treatment of ischemic stroke. The exact mechanism of this enhancement has not yet been elucidated. In this work, stable and inertial cavitation (SC and IC) are investigated as possible mechanisms for this enhancement. A passive cavitation detection scheme was utilized to measure cavitation thresholds at 120 kHz (80% duty cycle, 1667 Hz pulse repetition frequency) for four host fluid and sample combinations: plasma, plasma with rt-PA, plasma with clot and plasma with clot and rt-PA. Following cavitation threshold determination, clots were exposed to pulsed ultrasound for 30 min in vitro using three separate ultrasound treatment regimes: (1) no cavitation (0.15 MPa), (2) SC alone (0.24 MPa) or (3) SC + IC combined (0.36 MPa) in the presence of rt-PA. Percent clot mass loss after each treatment was used to determine thrombolysis efficacy. The highest percent mass loss was observed in the stable cavitation regime (26%), followed by the combined stable and inertial cavitation regime (20.7%). Interestingly, the percent mass loss in clots exposed to ultrasound without cavitation (13.7%) was not statistically significantly different from rt-PA alone (13%) [p > 0.05]. Significant enhancement of thrombolysis correlates with presence of cavitation and stable cavitation appears to play a more important role in the enhancement of thrombolysis. |
| Title |
Correlation of tissue constituents with the acoustic properties of skin and wound. |
| Author |
Olerud JE, O'Brien WD Jr, Riederer-Henderson MA, Steiger DL, Debel JR, Odland GF. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1990 |
| Abstract |
The purpose of this study was to compare measurements of ultrasound properties of skin and wound tissue with measurements of material properties such as total collagen concentration, acetic acid soluble collagen concentration, water concentration, and.morphologic properties. Using a scanning laser acoustic microscope (SLAM), both ultrasonic speed and attenuation coefficient values were obtained for control skin (2-3 cm from the wound), for skin immediately adjacent to wounds (within 0.3 mm), as well as for wound tissue itself. The attenuation coefficient and speed measurements were lowest for wound tissue followed by adjacent skin and then control skin. As the wounds healed there appeared to be an increase in both speed and attenuation coefficient although the wound age at which these increases started and the length of time for which they continued varied from one dog to the next. The precision of duplicate sample measurement of wave speed was +/- 1.7% for control skin, whereas that for attenuation coefficient it was +/- 16%. Both ultrasonic speed and attenuation coefficient were directly correlated with tissue.collagen concentration and inversely correlated with tissue water concentration (p less than 0.001). Attenuation coefficient correlated best (r = 0.73) with acetic acid soluble collagen concentration which reflects the changes in collagen taking place.during the repair process. These attenuation measurements made at 100 MHz using the SLAM were compared for control skin.and wound samples with measurements made at 10-40 MHz using backscatter acoustic techniques (BAT). The tissue samples analyzed by each ultrasound technique were from adjacent locations on the animals. |
| Title |
Correlation of tissue constituents with the acoustic properties of skin and wound. |
| Author |
Olerud JE, O'Brien WD Jr, Riederer-Henderson MA, Steiger DL, Debel J, Odlnad GF. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1990 |
| Abstract |
The purpose of this study was to compare measurements of ultrasound properties of skin and wound tissue with measurements of material properties such as total collagen concentration, acetic acid soluble collagen concentration, water concentration, and morphologic properties. Using a scanning laser acoustic microscope (SLAM), both ultrasonic speed and attenuation coefficient values were obtained for control skin (2–3 cm from the wound), for skin immediately adjacent to wounds (within 0.3 mm), as well as for wound tissue itself. The attenuation coefficient and speed measurements were lowest for wound tissue followed by adjacent skin and then control skin. As the wounds healed there appeared to be an increase in both speed and attenuation coefficient although the wound age at which these increases started and the length of time for which they continued varied from one dog to the next. The precision of duplicate sample measurement of wave speed was ±1.7% for control skin, whereas that for attenuation coefficient it was ±16%. Both ultrasonic speed and attenuation coefficient were directly correlated with tissue collagen concentration and inversely correlated with tissue water concentration (p < 0.001). Attenuation coefficient correlated best (r = 0.73) with acetic acid soluble collagen concentration which reflects the changes in collagen taking place during the repair process. These attenuation measurements made at 100 MHz using the SLAM were compared for control skin and wound samples with measurements made at 10–40 MHz using backscatter acoustic techniques (BAT). The tissue samples analyzed by each ultrasound technique were from adjacent locations on the animals. |
| Title |
Correlation of ultrasonic and endocrinologic assessment of human follicular development. |
| Author |
Hackeloer BJ, Fleming R, Robinson HP, Adam AH, Coutts JR. |
| Journal |
Am J Obstet Gynecol |
| Volume |
|
| Year |
1979 |
| Abstract |
Human ovarian follicular development measured by peripheral plasma hormone levels and ovarian follicular growth assessed by ultrasonic visualization of the ovary were compared and contrasted in apparently normally menstruating women. The linear correlation coefficient between the mean values for plasma estradiol and follicular diameter on day -5 to day 0 of 15 normal cycles was r = 0.968. When the individual paired data were subjected to multiple linear regression analyses (on days -5 to 0), r = 0.771. These good correlations show that ultrasound measurements of follicular diameter are valuable in the assessment of follicular growth and development. Observations on apparently abnormal cycles are also discussed. Ultrasound measurement of follicular diameter offers an additional technique for the study of ovarian function. |
| Title |
Correlation of ultrasonic attenuation with pathologic fat and fibrosis in liver disease. |
| Author |
Lin T, Ophir J, Potter G. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1988 |
| Abstract |
The attenuation coefficient in two groups (n1 = 70; n2 = 59) of pathologically graded in vitro human liver specimens was measured over a frequency range from 1.25-8.0 MHz and fitted to a power law model. The slopes of the power law curves at 5 MHz were correlated with pathological scores for fat in Group I, which consisted of normal and fatty livers (no fibrosis); they were also correlated with the pathological score for fibrosis in Group II, which consisted of normal and fibrotic livers (no intracellular fat). Significant (p less than 0.002) differences were found between the two groups. The fatty liver group exhibited approximately a 0.23 +/- 0.06 dB.cm-1 MHz-1 (fat grade)-1 behavior (mean +/- s.d.), while the fibrotic liver group exhibited approximately a 0.11 +/- 0.01 dB cm-1 MHz-1 (fibrosis grade)-1 behavior. These results may explain some of the conflicting literature in this area, and suggest that attenuation may in principle be used for screening for liver disease, but not for differentiation between fatty and fibrotic conditions. |
| Title |
Correlation of ultrasound parameter imaging with microcirculatory patterns in uveal melanomas. |
| Author |
Silverman RH, Folberg R, Boldt HC, Lloyd HO, Rondeau MJ, Mehaffey MG, Lizzi FL, Coleman DJ. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1997 |
| Abstract |
Previous studies demonstrated a correlation between acoustic backscatter parameters and survival in ocular.melanoma. The histologic presence of microvascular networks in ocular melanoma is also associated with death from.metastases. This study tests the hypothesis that melanomas grouped on the basis of these microvascular patterns are.separable by ultrasound spectrum analysis. We scanned 40 melanomas using a 10-MHz ultrasound unit equipped for.digitization of radio frequency data. After enucleation, tumors were sectioned in planes corresponding to the.ultrasonographic examination and stained to demonstrate microcirculation. Acoustic spectral parameters were.compared between 14 melanomas with a nevuslike microcirculation and 26 with foci of high-risk microvascular.structures. Smaller scatterer size, lower acoustic concentration and greater spatial variability were found to correlate.with high-risk microvascular patterns and areas of cystic degeneration. We suggest that nonvascular extracellular.matrix components associated with microvessels may be responsible for the correlation of acoustic parameters with.microvascular pattern and distribution. |
| Title |
Correlation of ultrasound-induced hemolysis with cavitation detector output in vitro. |
| Author |
Everbach EC, Makin IR, Azadniv M, Meltzer RS. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1997 |
| Abstract |
A 20-MHz passive acoustic detector was used to quantify the amount of transient.acoustic cavitation occurring in a sample exposed to intense pulsed ultrasound. A.dilute suspension of human erythrocytes with and without a microbubble.echo-contrast agent was exposed in vitro to 500 W/cm(^2) (SPPA) ultrasound of.center frequency 1 MHz and tone burst duration 20, 100, 200, 500 and 1000.microseconds at a pulse repetition frequency of 20 Hz. Inertial cavitation.occurring within the sample, as measured by the temporal average of the detector.output, correlated well with hemolysis, suggesting that violent bubble collapse is.responsible for cell damage. The result also raises the prospect of cavitation.monitoring as a possible predictor of adverse bioeffects when echo-contrast.agents are used clinically. |
| Title |
Correlations between ultrasound velocities in the human tibia measured over the medial surface and entire bone. |
| Author |
Dzenis VV, Yanson KA. |
| Journal |
Plenum Pub Corp |
| Volume |
|
| Year |
1984 |
| Abstract |
No abstract available. |
| Title |
Correlative study of properties of water in biological systems using.ultrasound and magnetic resonance. |
| Author |
Sehgal CM, Greenleaf JF. |
| Journal |
Magn Reson Med |
| Volume |
|
| Year |
1986 |
| Abstract |
Ultrasonic and nuclear magnetic resonance properties of media rich in water are investigated. The chemical shift of the water proton in pure water, aqueous solutions of tertiary butanol, and sodium chloride is shown to be linearly correlated to the.reciprocal of sound speed in these media. A new method of determining the self-diffusion coefficient of water by using acoustic nonlinearity and sound speed is proposed. The method is tested on a variety of media that include pure water,.aqueous solutions of glycerol, serum albumin, egg constituents, plant tissues, frog muscle and liver, and excised human tissues. In all the cases the results are found to compare closely to diffusion coefficients measured by magnetic resonance..The results presented here indicate that the acoustic and magnetic resonance modalities, though inherently different in their origin, can provide closely related information on the properties of water. |
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