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BRL Abstracts Database |
Your search for ultrasound produced 3296 results. Page 243 out of 330
Title |
Synthetic aperture-based beam compression for intravascular ultrasound imaging. |
Author |
Vray D, Haas C, Rastello T, Krueger M, Brusseau E, Schroeder K, Gimenez G, Ermert H. |
Journal |
IEEE Trans UFFC |
Volume |
|
Year |
2001 |
Abstract |
In this paper, intravascular ultrasound (IVUS) images acquired with a 64-element array transducer using a multistatic acquisition scheme are presented. The images are reconstructed from a collection of pulse-echo measurements using a synthetic aperture array imaging technique. The main limitations of IVUS imaging are a poor lateral resolution and elevated grating lobes caused by the imaging geometry. We propose a Synthetic Aperture Focusing Technique (SAFT), which uses a limited number of A-scan signals. The focusing process, which is performed in the Fourier domain, requires far less computation time than conventional delay-and-sum methods. Two different reconstruction kernel functions have been derived and are compared for the processing of experimental data. |
Title |
Synthetic applications of ultrasound. |
Author |
Suslick KS. |
Journal |
Modern Synthe Methods |
Volume |
|
Year |
1986 |
Abstract |
No abstract available. |
Title |
System design of a clinical facility for diagnostic ultrasound. |
Author |
Lapayowker MS, Carlsen E, Dick DE, Doust BD, Goldberg BB, Lyons EA, McGimsey DR, Staiano SJ, Watson JL, Zahorik DJ. |
Journal |
Rep AEMB |
Volume |
|
Year |
1977 |
Abstract |
This System Design of a Clinical Facility for Diagnostic Ultrasound sets out the fundamental considerations that are necessary for the successful development and functioning of a clinical diagnostic ultrasound facility. Part 1, Establishing a Clinical Diagnostic Ultrasound Facility, deals with the myriad details that must be considered when establishing such a facility, including the type of facility best suited to the needs of the particular institution, space and equipment requirements, support services, and the facility's personnel and their training. A definition of ultrasound techniques also is discussed in this section. Part 2, Managing a Clinical Diagnostic Ultrasound Facility, is concerned with the functioning of the facility once it is established. Particular stress is placed on the well-being and comfort of the patients, both before and after they arrive at the facility. This section also deals with record keeping, the actual or potential teaching and research functions of the facility, preparation and maintenance of equipment, and the responsibilities of the administrative, professional, and paraprofessional personnel. A short bibliography is in Part 3, as well as a list of those to whom this document was sent for review and comment. |
Title |
System desing of a clinical facility for diagnostic ultrasound. |
Author |
Alliance for engineering for medicine and biology. Task group I. |
Journal |
Rep AEMB |
Volume |
|
Year |
1977 |
Abstract |
The System Design of a Clinical Facility for Diagnostic Ultrasound sets out the fundamental considerations that are necessary for the successful development and functioning of a clinical diagnostic ultrasound facility. |
Title |
Table of integral functions describing diffraction effects in the ultrasound field of a circular piston source. |
Author |
Benson GC, Kiyohara O. |
Journal |
Rep Natl Res Counc Can |
Volume |
|
Year |
1973 |
Abstract |
No abstract available. |
Title |
Tactile perception of ultrasound. |
Author |
Dalecki D, Child SZ, Raeman CH, Carstensen EL. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1995 |
Abstract |
In this investigation, acoustic radiation force was used as a stimulus to determine the threshold for tactile perception in the human finger and upper forearm as a function of frequency and pulse duration. Initially, a small (1.8-cm2) acoustically reflecting disk was affixed to the anatomical exposure site to maximize the delivered radiation force. Exposures were performed using a 2.2-MHz unfocused source modulated to produce square waves at 50, 100, 200, 500, and 1000 Hz. For the finger, maximum tactile sensitivity occurred at 200 Hz with a threshold radiation force of approximately 0.4 mN. For single pulses of 1 to 100 ms at 2.2 MHz, the threshold forces were an.order of magnitude greater than for continuous exposure modulated at 200 Hz. Thresholds for pulse durations of 0.1 ms were somewhat greater than for pulses longer than 1 ms. Subsequently, thresholds of tactile perception were determined for direct exposure of the upper forearm (avoiding bone) to single pulses of 2.2-MHz ultrasound. Comparison of perception thresholds with and without a reflecting material over the tissue were consistent with the hypothesis that the tactile sensation experienced when tissue is exposed to ultrasound is its response to the radiation force associated with the transfer of momentum from the sound field to the tissue medium. . |
Title |
Tapping the medical potential of ultrasound. |
Author |
Freiherr G. |
Journal |
Res Resour Rep |
Volume |
|
Year |
1986 |
Abstract |
No abstract available. |
Title |
Targeted imaging using ultrasound contrast agents. |
Author |
Bloch SH, Dayton PA, Ferrara KW. |
Journal |
IEEE Med Biol |
Volume |
|
Year |
2004 |
Abstract |
The applications of ultrasound contrast agents have recently expanded from blood pool enhancement to include passive targeting of physiological systems (in particular, the lymphatic and reticuloendothelial systems) and molecular imaging of factors expressed in angiogenesis, atherosclerosis, and inflammation. This article summarizes the progress made in targeted imaging using ultrasound with an emphasis on the opportunities this research provides for both clinical and research applications. We begin with a summary of current ultrasound contrast technology and then review the latest research in the use of targeted ultrasound contrast agents. |
Title |
Technical evaluation of an ultrasound CT scanner. |
Author |
Dick DE, Carson PL, Bayly EJ, Oughton TV, Kubicheck JE, Kitson FL. |
Journal |
Proc Ultrason Symp IEEE |
Volume |
|
Year |
1977 |
Abstract |
Ultrasonic CT images, using time-of-flight data, have been reported and shown to yield quantitative tissue characteristics with promising clinical utility. Attenuation images have been less satisfactory. An improved ultrasound CT scanner has been constructed and used to produce human breast attenuation images. The system has been evaluated for the major artifacts normally encountered in CT imaging. Specific areas of concern include signal processing, display, geometric errors, and refraction. The effect of each of these factors has been studied in order to identify remaining system limitations and to make further improvements in image quality. |
Title |
Technique for measuring the velocity of sound in liquids in the frequency range from 20 to 1000 kHz. |
Author |
Iigunas V, Leonavichyus G, Stripins E. |
Journal |
Sov Phys Acoust |
Volume |
|
Year |
1976 [1976] |
Abstract |
A new technique is described for measuring the velocity of ultrasound in liquids with the use of open cylindrical or spherical confocal resonators. The velocity of sound is determined from the difference between adjacent natural frequencies of the resonator and twice the distance between the piezoelectric transducers forming it. Data are given from measurements in water, an aqueous sodium chloride solution, and glycerin. The error of the proposed technique is from 0.05 to 0.1%. |
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