ISSN:0091-2751    

DOI:10.1002/jcu.1870100315

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0091-2751    

DOI:10.1002/jcu.1870100316

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0091-2751    

DOI:10.1002/jcu.1870100317

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThree prototype anthropomorphic breast phantoms are discussed. The phantoms were constructed using ultrasonically tissue‐mimicking materials; these materials mimic various tissue parenchymae in terms of attenuation, speed of sound, density, and scatter level. Realistic artifacts related to refraction and reflection at interfaces between different simulated parenchymae are produced. The phantoms represent premenopausal breasts, and they complement one another. Two of them represent the dense breasts of women under 30 years of age, and one represents that of a woman between 35 and 40 years of age. Of the former two, one produces what is apparently above‐average refraction effects in the region of the peripheral fat layer; the other produces more typical refraction effects. Simulated tumors, cysts, and calcifications of various sizes are suspended in the glandular regions. Such phantoms are valuable for use in developmental testing of state‐of‐the‐art ultrasound machines, quality assurance testing of clinical machines, and training of sonographers in breas

ISSN:0091-2751    

DOI:10.1002/jcu.1870100302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractPulsed Doppler echocardiography and digital Fourier analysis were utilized to examine flow distal to the aortic valve and to quantify aortic stenosis. A graphic index of parameters derived from velocity spectrum patterns generated by Fourier analysis was regressed against mean systolic pressure gradients in 21 adults with clinical evidence of aortic stenosis who underwent catheterization studies and five normal adults (r= .82). Correlation improved in the absence of regurgitation (r= .92). Sensitivity for detecting gradients>30 mmHg was 86%; specificity was 90%. Doppler spectral analysis shows promise in alleviating the need for many invasive studies.

ISSN:0091-2751    

DOI:10.1002/jcu.1870100303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe peak frequency ratio (PFR) between the internal carotid and common carotid artery Fast Fourier Transform Spectral Analysis patterns has been used to identify patients with internal carotid artery stenosis. To evaluate further the accuracy of the PFR, we applied it to the spectral analysis data from 396 vessels whose sound signals were obtained with a Duplex scanner (pulsed Doppler) and 246 arteries whose audible flow data were generated by a continuous‐wave Doppler. The pulse Doppler with spectral analysis (PD/SA) correctly identified 221/254 (87%) of the vessels with less than 50% angiographic stenosis, 81/100 (81%) of the arteries with 50–99% stenosis, and 35/42 (83%) of the totally occluded internal carotid vessels for an overall accuracy of 85%. The continuous‐wave Doppler with spectral analysis (CW/SA) did well in two categories but had an unacceptably high 47% false‐negative rate for arteries with 50–99% stenosis. The PFR when applied to PD/SA test results is a useful parameter in screening patients with suspected internal carotid artery

ISSN:0091-2751    

DOI:10.1002/jcu.1870100304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe sonographic Murphy sign, the presence of maximal tenderness elicited over a sonographically localized gallbladder, has been considered useful in the evaluation of patients with suspected acute cholecystitis. We prospectively evaluated this sign in 427 consecutive patients referred for evaluation of acute cholecystitis. The overall accuracy of the sonographic Murphy sign in the 219 patients with sufficient confirmation to be included in the statistical analysis was 87.2%. Sensitivity was 63% and specificity was 93.6%. The predictive value of a positive sign was 72.5%, while the predictive value of a negative sign was 90.5%. The sonographic Murphy sign is a useful, albeit imperfect, adjunct in the assessment of patients with suspected acute cholecystitis.

ISSN:0091-2751    

DOI:10.1002/jcu.1870100305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractInjection of liquid through a catheter into the circulation is known to produce clouds of signals detected by sonography. Blood forced through a stenotic conduit produced sonographic clouding, and bubbles of 10–100 μm were observed by light microscopy. The microbubbles persisted up to three and a half minutes. Microbubbles were observed in the microcirculation of the rat by placing the catheter tip into the descending aorta of 15 animals, viewing the mesentery at 400X magnification, and recording the results on videotape. Following injection of the rats' own blood, numerous microbubbles lodged promptly at the arteriolar level and obstructed blood flow for up to 200 sec before shrinking sufficiently to pass downstream and allow restitution of fl

ISSN:0091-2751    

DOI:10.1002/jcu.1870100306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0091-2751    

DOI:10.1002/jcu.1870100307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0091-2751    

DOI:10.1002/jcu.1870100308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY