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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 242 out of 330
| Title |
Supervised pattern recognition techniques in quantitative diagnostic ultrasound. |
| Author |
Insana MF, Wagner RF, Garra BS, Momenan R, Shawker TH. |
| Journal |
J Clin Eng |
| Volume |
|
| Year |
1988 |
| Abstract |
The methods of statistical pattern recognition are well suited to the problems of in vivo ultrasonic tissue characterization. This paper describes supervised pattern recognition methods for selecting features for tissue classification, calculating decision boundaries within the selected feature space, and evaluating the performance. This paper expands on the authors' previous work (Insana, 1986a) by addressing the considerations of dimensionality and sample size. These are important in classification problems where the underlying probability distributions are not completely known. Examples are given for the detection of diffuse liver disease in the clinical environment. |
| Title |
Suprasternal ultrasonography. |
| Author |
Goldberg BB. |
| Journal |
JAMA |
| Volume |
|
| Year |
1971 |
| Abstract |
Ultrasound has been used to measure the diameters of the aortic arch, right pulmonary artery, and left atrium. This new method is described in detail. The transducer is placed in the suprasternal region and the ultrasonic beam is directed caudad. Cadaver and clinical experiments have confirmed the reliability of the ultrasonic results. Suprasternal ultrasonic readings were obtained on 100 patients, including 52 normals, 18 with hypertensive cardiovascular disease, 24 with rheumatic heart disease, and 6 with congenital heart disease. Excellent correlation between the ultrasonic and angiographic lumen measurements in both healthy and diseased subjects was shown. |
| Title |
Surgical application of the high intensity focused ultrasound. I. Outline of selective focal destruction of the central nervous system and preliminary report of several neurosurgical experiences. |
| Author |
Oka M, Okumura T, Yokoi H, Murao T, Miyashita Y, Ota K, Yoshitatsu S, Yoshioka K, Hirano H, Kawashima Y |
| Journal |
Med J Osaka Univ |
| Volume |
|
| Year |
1960 |
| Abstract |
No abstract available. |
| Title |
Survival of Drosophila melanogaster pupa exposed to ultrasound. |
| Author |
Pay TL, Andersen FA, Jessup GL Jr. |
| Journal |
Radiat Res |
| Volume |
|
| Year |
1978 |
| Abstract |
Drosophila melanogaster pupa were exposed to 1-MHz continuous wave ultrasound. Exposure ranged from 0.2 to 4.0 W/cm(2) (spatially average acoustic intensities) for 10-min continuous exposure. The LD(50/7) was calculated to be 0.7 W/cm(2). All pupa receiving an exposure greater than 1.5 W/cm(2) failed to emerge into adults, but a number of these continued to develop to a point 78 hr postexposure. These pupae displayed abnormal eye pigmentation and abnormal eye and thorax development. |
| Title |
Swept-frequency diffraction of ultrasound by cylinders and arrays. |
| Author |
Lee PPK, Waag RC, Hunter LP. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1978 |
| Abstract |
Diffraction of ultrasound in water by single cylinders and arrays of equally spaced cylinders is studied experimentally using a swept-frequency technique and the results are compared with theoretical predictions. Scattering of single metallic cylinders is computed from a model which includes the effect of reverberations within the cylinder. A one-dimensional, single-scattering approximation is used for data reduction in the case of the regular array where Fourier inversion of the data is used to determine the scatterer spacing of the array. Swept-frequency measurements were made in a fixed geometry using long pulses of sinusoidal signal whose center frequency was essentially constant during the pulse interval but was varied over the total sequence of pulses. The observed scattering spectrum of a single metallic cylinder agrees closely with the calculated prediction. The Fourier transformation spectra of the array scattering data shows good agreement with the known scatterer spacing even when the data were taken in the nearfield and the data are reduced using a plane wave, farfield assumption. This investigation provides a foundation for additional studies of factors involved in the use of ultrasound diffraction in tissue characterization. |
| Title |
Swept-frequency ultrasonic determination of tissue macrostructure. |
| Author |
Waag RC, Lerner RM, Gramiak R. |
| Journal |
Proc Semin Ultrason Tissue Character - Gaithersburg |
| Volume |
|
| Year |
1975 |
| Abstract |
Ultrasound may be used to determine the acoustic structure of tissue on a scale corresponding to the wavelengths employed by using the scattered signal to infer the organization of tissue elements. The underlying concept is the selective reinforcement or cancellation of certain frequencies depending on the relation of wavelength, reflector spacing, and orientation. A Fourier analysis of the received signal as a function of frequency or scattering angle reveals the acoustic variations corresponding to structure. Data similar to that obtained by angle scanning at a fixed frequency in X-ray diffraction has been recorded. Predicted deterministic interference patterns have been demonstrated for aluminum plates. Random scattering for two different sizes of dextran particles has also demonstrated predicted differences in scattering spectra. Pilot studies of liver specimens have shown marked variations in intensity-frequency distributions for individual disease processes. |
| Title |
Symposium on recent studies in the safety of diagnostic ultrasound. The development of low power ultrasonic instruments. |
| Author |
Morohashi T, Iizuka R. |
| Journal |
Jpn J Med Ultrasound |
| Volume |
|
| Year |
1977 |
| Abstract |
1) Clinically useful gray scale B-mode images were obtained in 1000 obstetrical cases in the use of a new ultrasonic manual scan equipment with the intensity as low as 1/55 and the repetition rate as low as 1/10 comparing conventional contact compound scan devices.
2) Useful results were obtained in the detection of fetal heart beat in the early pregnancy in the use of a new low power ultrasonic Doppler fetal detector in 1000 cases with the intensity of 0.4 mW/cm2
3) In an epidemiological study in Kei-O University hospital utilizing ultrasonic Doppler detector with the ultrasonic intensity below 10mW/cm2 in 12083 cases neonatal anomaly was found in 0.21% in 1950 cases tested in the stage of organogenesis. The rate was 0.20% in 10133 cases tested after the organogenesis stage. No significant difference was found among these two groups. Abortion rate was higher in the cases tested after the organogenesis stage than those examined before the stage.
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| Title |
Synergism between ultrasound and X rays in tumour therapy. |
| Author |
Clarke PR, Hill CR, Adams K. |
| Journal |
Br J Radiol |
| Volume |
|
| Year |
1970 |
| Abstract |
No abstract available. |
| Title |
Synergistic effect of ultrasound and hematoporphyrin on sarcoma 180. |
| Author |
Yumita N, Nishigaki R, Umemura K, Umemera S-i. |
| Journal |
Jpn J Cancer Res |
| Volume |
|
| Year |
1990 |
| Abstract |
The antitumor effects of combined use of ultrasound (US) and a photosensitizer, hematoporphyrin (Hp), were determined in mice bearing sarcoma 180. In order to find the optimum timing of the US irradiation after the administration of Hp, the Hp concentrations in the tumor and in the plasma were determined and were analyzed pharmacokinetically. Antitumor effects were evaluated by measuring the tumor size and the tumor weight. Hp alone showed no antitumor effect but US alone showed a slight antitumor effect. The combined treatment with US and Hp showed marked synergistic effects on sarcoma 180 (inhibition ratio was 74% of the control). From these results, the enhancement of antitumor effect is thought to be caused by the sensitization of tumor cells to US mediated by Hp. |
| Title |
Synergistic effects of ultrasound-activated microbubbles and doxorubicin on short-term survival of mouse mammary tumor cells. |
| Author |
Ghoshal G, Swat S, Oelze M. |
| Journal |
Ultrasound Imaging |
| Volume |
|
| Year |
2012 |
| Abstract |
The primary focus of this paper is to quantify the therapeutic synergism when combining ultrasound,ultrasound contrast agents (UCAs) and doxorubicin for breast cancer treatment using an in vitro experimental configuration with mouse mammary tumor (4T1) cells. The 4T1 cells were grown in 96 well plates and allowed to grow to 90% confluency. A 1-MHz focused (f/3) single-element transducer was used to expose the microbubbles (MBs) (Definity) with ultrasound near the surface of the cells. After the ultrasound exposure, different doses of doxorubicin were added and incubated for 24 hours at 37 °C,100% humidity and 5% CO2. The efficacies of the drug only and ultrasound-activated MBs combined with drug therapies to kill cells were then quantified by analyzing the cell viability after 24 hours of treatment using the MTT Cell Proliferation Assay. The combined therapy resulted in 60±5.9% of cell viability compared to 82±4.5% when only doxorubicin was used. The cell viability was 72±5.8% when only ultrasound-activated MBs were used with a similar acoustic pressure condition. No significant increase in cell death was observed for higher concentrations of doxorubicin whereas higher peak negative pressure of the ultrasound wave resulted in increased cell death. |
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