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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 2 out of 330
| Title |
'Son et lumiere': A new combined optical and Doppler ultrasound approach to the detection of breast cancer. |
| Author |
Watmough DJ, Moran C, Watmough JA. |
| Journal |
J Biomed Eng |
| Volume |
|
| Year |
1988 |
| Abstract |
X-ray mammography is the gold standard for diagnosis of lesions within the female breast. It is also recognized as the technique of choice for breast cancer screening in women over 50-years-old. Notwithstanding these important roles it has shortcomings in terms of limited sensitivity and specificity, especially in younger women. This paper describes the concept of a combined optical density and Doppler ultrasound method proposed initially as a supplement to mammography. A specially devised tissue compressor is also described. Results obtained using test phantoms and initial clinical studies are presented. Neovascularization at the advancing front of neoplastic lesions is believed to underlie detection of lesions by both telediaphanography and Doppler ultrasound. |
| Title |
1.5-D high intensity focused ultrasound array for non-invasive prostate cancer surgery. |
| Author |
Curiel L, Chavrier F, Souchon R, Birer A, Chapelon JY. |
| Journal |
IEEE Trans Ultrason Ferroelectr Freq Control |
| Volume |
|
| Year |
2002 |
| Abstract |
The aim of this study is to demonstrate the feasibility of a new spherically curved 1.5-D phased array for the treatment of localized prostatic cancer. The device is designed to conform to the Ablatherm machine (EDAP-Technomed, France), a commercially available machine in which high intensity focused ultrasound (HIFU) treatment for prostate cancer is administered transrectally. It uses high intensity electronically focused ultrasound to steer a beam along two axes, allowing enough depth to be reached to treat large prostates and eliminating two degrees of mechanical movement. Through computer simulation, it was determined that a curved 1.5-D configuration offered the optimal design. Two configurations were then proposed, and their ability to steer a beam within a target volume centered on the geometric focus of the transducer was simulated. An eight-element prototype was constructed to test the piezo-composite material and its electro-acoustical efficiency. Then, an array was constructed, and a multi-channel amplifier and control system were added, to permit remote operation. Acoustical and electrical measurements were made to verify performance. Finally, the 1.5-D array was tested in vitro on samples of pig liver to confirm the ability to induce lesions. |
| Title |
1985 Acoustical data for diagnostic ultrasound equipment. |
| Author |
Unknown. |
| Journal |
Rep AIUM |
| Volume |
|
| Year |
1985 |
| Abstract |
No abstract available. |
| Title |
1993 Annual Report. |
| Author |
Unknown. |
| Journal |
Rep Univ Rochester Cent Biomed Ultrasound |
| Volume |
|
| Year |
1993 |
| Abstract |
No abstract available. |
| Title |
1994 Annual Report. |
| Author |
Various. |
| Journal |
Rep Univ Rochester Cent Biomed Ultrasound |
| Volume |
|
| Year |
1994 |
| Abstract |
A summary of research projects. |
| Title |
25 megahertz gastrointestinal ultrasonography. |
| Author |
Wiersema MJ, Reilly CR, Sanghvi NT, Hawes R, Wiersema L, Aust C. |
| Journal |
Proc Ultrason Symp IEEE |
| Volume |
|
| Year |
1989 |
| Abstract |
Endoscopic gastrointestinal ultrasonography provides the only method of in vivo evaluation of all gastrointestinal wall layers and surrounding structures. Higher frequencies (7.5 and 12 MHz) have been used due to the proximity of the transducer to the bowel wall. In an attempt to define the tissue characteristics at a macroscopic level and differentiate their structural content as a function of backscattering, we have employed a 25 MHz transceiver, high speed digitizer and high resolution display in a conventional in vitro pulse-echo system. A linear B-mode scan constructed from digitized A-modes is stored in the microcomputer and displayed in grey scale (257 levels) on a high resolution monitor. Transducer characterization yielded focal lateral and axial resolutions of 200 and 100 micrometers, respectively. We have compiled over 250 scans of normal and diseased postmortem and surgical specimens from the esophagus, stomach, small intestine, colon and rectum. These ultrasound images were then correlated to corresponding histologic sections taken from the scan plane. Images at this higher frequency demonstrate and enhanced ability to distinguish the microscopic layers of the gastrointestinal wall when compared to conventional endoscopic ultrasonography. The ultrasound tissue texture characterization allows greater contrast between neoplastic and surrounding normal structures. Preliminary results suggest that 25 MHz imaging may allow better tumor staging and more accurate thickness measurments. |
| Title |
3-D in vitro estimation of temperature using the change in backscattered ultrasonic energy. |
| Author |
Arthur R, Basu D, Guo Y, Trobaugh J, Moros E. |
| Journal |
IEEE Trans Ultrason Ferroelectr Freq Control |
| Volume |
|
| Year |
2010 |
| Abstract |
Temperature imaging with a non-invasive modality to monitor the heating of tumors during hyperthermia treatment is an attractive alternative to sparse invasive measurement. Previously, we predicted monotonic changes in backscattered energy (CBE) of ultrasound with temperature for certain sub-wavelength scatterers. We also measured CBE values similar to our predictions in bovine liver, turkey breast muscle, and pork rib muscle in 2-D in vitro studies and in nude mice during 2-D in vivo studies. To extend these studies to three dimensions, we compensated for motion and measured CBE in turkey breast muscle. 3-D data sets were assembled from images formed by a phased-array imager with a 7.5-MHz linear probe moved in 0.6-mm steps in elevation during uniform heating from 37 to 45 degrees C in 0.5 degrees C increments. We used cross-correlation as a similarity measure in RF signals to automatically track feature displacement as a function of temperature. Feature displacement was non-rigid. Envelopes of image regions, compensated for non-rigid motion, were found with the Hilbert transform then smoothed with a 3 x 3 running average filter before forming the backscattered energy at each pixel. CBE in 3-D motion-compensated images was nearly linear with an average sensitivity of 0.30 dB/ degrees C. 3-D estimation of temperature in separate tissue regions had errors with a maximum standard deviation of about 0.5 degrees C over 1-cm(3) volumes. Success of CBE temperature estimation based on 3-D non-rigid tracking and compensation for real and apparent motion of image features could serve as the foundation for the eventual generation of 3-D temperature maps in soft tissue in a non-invasive, convenient, and low-cost way in clinical hyperthermia. |
| Title |
3-D ultrasound imaging of the prostate. |
| Author |
Fenster A, Tong S, Downey DB. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1998 |
| Abstract |
No Abstract Available. |
| Title |
3D prostate model formation from non-parallel 2D ultrasound biopsy images. |
| Author |
Cool D, Downey D, Izawa J, Chin J, Fenster A. |
| Journal |
Med Image Anal |
| Volume |
|
| Year |
2006 |
| Abstract |
Biopsy of the prostate using 2D transrectal ultrasound (TRUS) guidance is the current gold standard for diagnosis of prostate cancer; however, the current procedure is limited by using 2D biopsy tools to target 3D biopsy locations. We propose a technique for patient-specific 3D prostate model reconstruction from a sparse collection of non-parallel 2D TRUS biopsy images. Our method conforms to the restrictions of current TRUS biopsy equipment and could be efficiently incorporated into current clinical biopsy procedures for needle guidance without the need for expensive hardware additions. In this paper, the model reconstruction technique is evaluated using simulated biopsy images from 3D TRUS prostate images of 10 biopsy patients. All reconstructed models are compared to their corresponding 3D manually segmented prostate models for evaluation of prostate volume accuracy and surface errors (both regional and global). The number of 2D TRUS biopsy images used for prostate modeling was varied to determine the optimal number of images necessary for accurate prostate surface estimation. |
| Title |
3D ultrasonic image feature localization based on magnetic scanhead tracking: In vitro calibration and validation. |
| Author |
Detmer PR, Bashein G, Hodges T, Beach KW, Filer EP, Burns DH, Strandness DE Jr. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1994 |
| Abstract |
The basis of a three-dimensional (3D) ultrasound imaging system was constructed from a commercially available magnetometer-based position and orientation measurement (POM) device, a standard B-Mode ultrasound instrument and a personal computer. To evaluate the system's performance, a novel method was devised using an iterative, least-squares technique to simultaneously determine the system's calibration parameters and measure its precision in locating points in three-dimensional space. When tested separately, the POM system located single points with a root mean squared (RMS) uncertainty of from 1.4 mm to 3.2 mm over the 610 mm working radius of the system. When combined with the ultrasound instrument, the RMS uncertainty in locating point targets varied from 2.1 mm to 3.5 mm. These results establish the lower limits of variability to be expected from this system when locating fiducial anatomical landmarks for repeated examinations of the same region of the body, and when making numerical 3D reconstructions from multiple planar images. |
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