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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 295 out of 330
| Title |
Ultrasonic spectral-paramter imaging of the prostate. |
| Author |
Feleppa EJ, Liu T, Kalisz A, Shao MC, Fleshner N, Reuter V, Fair WR. |
| Journal |
Int J Imaging Syst Technol |
| Volume |
|
| Year |
1997 |
| Abstract |
Spectrum analysis of the radiofrequency echo signals obtained from ultrasonically scanning the prostate may provide information capable of distinguishing cancerous from noncancerous tissue. In American men, prostate cancer is the. highest-incidence cancer and the second-highest cancer killer. It is diagnosed using ultrasonically guided biopsies, which are limited by the low sensitivity and specificity of the guidance method. Spectrum analysis of the echo signals uses. information that is discarded by conventional ultrasound imaging technology. The inclusion of this information shows differences between the ultrasound-scattering properties of cancerous and noncancerous prostate tissues. Spectrum. analysis of ultrasonic echoes provides parameter values that can be related to scattering properties of tissue and can be compared to database parameter value ranges associated with cancerous and noncancerous tissues. Images can be. generated to display parameter values, scatterer properties, or most likely tissue type. Results to date suggest that these differences may be sufficient to improve biopsy guidance significantly and therefore to improve the efficacy of. biopsy-based diagnosis of prostate cancer. |
| Title |
Ultrasonic spectroscopic study of relaxation processes in aqueous solutions of nucleosides. |
| Author |
Braginskaya FI. |
| Journal |
Sov Phys Acoust |
| Volume |
|
| Year |
1975 |
| Abstract |
The absorption of ultrasound in aqueous solution of purine and pyrimidine nucleotides is investigated by means of a pulsed ultrasonic apparatus operating in the frequency range from 12 to 84 MHz. Relaxation processes are detected in the purine nucleoside solutions, and their acoustic relaxation parameters are calculated.. |
| Title |
Ultrasonic spectroscopy of the porcine eye lens. |
| Author |
van der Steen AFW, De Korte CL, Thijssen JM. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1994 |
| Abstract |
The purpose of the work is to measure and study the acoustic characteristics of the porcine eye lens and find correlations with chemical and optical parameters, obtained from literature. Ultrasonic spectroscopy was performed by using a scanning acoustic macroscope (frequency 20 MHz, resolution 150 microns). The transducer performed a two-dimensional scan over a central slice (1 mm thickness) of porcine lens (number of lenses = 10). A double transmission pulse-echo method was used to acquire the ultrasonic data from the lens. Two-dimensional images were reconstructed of the local ultrasound velocity and the frequency-dependent ultrasound attenuation. Axial and equatorial profiles of these parameters were calculated from the images. The acoustic parameters are not constant, but show a systematic dependence on the location within the lens. The profiles of the acoustic parameters are similar in shape to profiles of the protein and water contents of eye lens and to the profiles of the optical refractive index. A thorough quantitative correlation study is indicated, which should be based on detailed protein content data in porcine lenses. |
| Title |
Ultrasonic spectroscopy of the porcine eye lens. |
| Author |
van der Steen AFW, De Korte CL, Thijssen JM. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1994 |
| Abstract |
The purpose of the work is to measure and study the acoustic characteristics of the porcine eye lens and find correlations with chemical and optical parameters, obtained from literature. Ultrasonic spectroscopy was performed by using a scanning acoustic macroscope (frequency 20 MHz, resolution 150 microns). The transducer performed a two-dimensional scan over a central slice (1 mm thickness) of porcine lens (number of lenses = 10). A double transmission pulse-echo method was used to acquire the ultrasonic data from the lens. Two-dimensional images were reconstructed of the local ultrasound velocity and the frequency-dependent ultrasound attenuation. Axial and equatorial profiles of these parameters were calculated from the images. The acoustic parameters are not constant, but show a systematic dependence on the location within the lens. The profiles of the acoustic parameters are similar in shape to profiles of the protein and water contents of eye lens and to the profiles of the optical refractive index. A thorough quantitative correlation study is indicated, which should be based on detailed protein content data in porcine lenses. |
| Title |
Ultrasonic stethoscope. |
| Author |
Unknown. |
| Journal |
Med Electron News |
| Volume |
|
| Year |
1972 |
| Abstract |
Ultrasound Stethoscope can determine presence of fetal life after uterus becomes abdominal, registers sounds of fetal heart, umbilical cord, and placenta. It also helps evaluate fetal condition during labor. |
| Title |
Ultrasonic studies in binary solutions of pyridine with water, methanol, and ethanol. |
| Author |
Thomas KN, Stumpf FB. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1973 |
| Abstract |
The velocity and absorption of ultrasound at 19.5 MHz were studied as a function of the concentration in binary solutions of pyridine with water, methanol, and ethanol. In addition, the compressibility and volume viscosity were calculated. Molecular processes are suggested to explain the variation of the ultrasonic properties of these binary solutions with respect to concentration. |
| Title |
Ultrasonic studies of molecular association in aqueous solutions of formic, acetic, propionic, and n-butyric acids. |
| Author |
Stumpf FB, Crum LA |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1966 |
| Abstract |
The absorption of ultrasound at 19 Mc/sec is studied, as a function of concentration in aqueous solutions of formic, acetic, propionic, and n-butyric acids. Peaks in the absorption-versus-concentration curves give the association ratios. The bonding mechanism responsible for the association is suggested. |
| Title |
Ultrasonic study of proton-transfer reactions in aqueous solutions of amino acids. |
| Author |
Chalikian TV, Kharakoz DP, Sarvazyan AP, Cain CA, McGough RJ, Pogosova IV, Gareginian TN. |
| Journal |
J Phys Chem |
| Volume |
|
| Year |
1992 |
| Abstract |
Ultrasonic velocity and absorption in dilute solutions of 12 amino acids have been measured over a wide pH range. Ultrasound velocity, volume, and compressibility changes in amino acids solutions due to ionization of amino and carboxyl groups were evaluated by means of a single-frequency method recently developed. The mutual influence of the amino and carboxyl groups on the hydrational volume and compressibility has been estimated quantitatively. An abnormal reverse sign of the compressibility change during ionization of the amino group in the amino acid skeleton has been found and leads to a question about the reliability of a previously published method of separation of the individual partial compressibilities of oppositely charged ions. |
| Title |
Ultrasonic three-dimensional imaging and volume from a series of arbitrary sector scans. |
| Author |
Brinkley JF, Moritz WE, Baker DW. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1978 |
| Abstract |
A computer-based system has been developed for generating a three-dimensional reconstruction of an organ as a series of arbitrary outlines from a real-time, two-dimensional ultrasonic sector scanner. This reconstruction can be viewed in perspective or used to find volume by an algorithm which assumes no a priori shape for the organ. The various outlines are obtained by positioning the scan head over the organ to be imaged and tracing the borders with a light pen. The position and orientation of each scan is obtained with a special acoustic position locating system allowing nearly complete freedom of motion of the scan head. .An initial feasibility test of this system has been done on seven balloons in a water tank. The correlation between measured and calculated volumes for 30 reconstructions on the seven balloons was R = 0.99, while the range of errors was -9.3 to +7.8%. Possible applications of this system include carotid artery imaging, fetal and liver volumes, and left ventricular volumes. |
| Title |
Ultrasonic three-dimensional reconstruction: in vitro and in vivo volume and area.measurement. |
| Author |
Hodges TC, Detmer PR, Burns DH, Beach KW, Strandness DE Jr. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1994 |
| Abstract |
This study validates the use of an ultrasound three-dimensional reconstruction system to measure phantom and blood conduit.geometry. Independently determined uniform and stenotic phantom dimensions are compared with reconstruction-based.measurements. Lower extremity saphenous vein bypass graft reconstructions were performed to demonstrate clinical application..Uniform phantom independent and reconstructed volume correlation was high (r = 0.989), the average volume difference was.4.68 mm3 and the average area difference was 0.4 mm2. An in vitro 28% diameter reduction was detected. Stenotic bypass graft.segment volume was 795 mm3; following successful angioplasty the volume increased to 1419 mm3. Advantages of this.technique are its accuracy, the luminal information it provides and the absence of mechanical arm or acoustic transmitter.limitations. We are exploring the possibility that measurement of luminal change over time may allow stenosis detection prior to.hemodynamic disturbance, in an ongoing clinical saphenous vein bypass graft surveillance study. |
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