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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 96 out of 330
| Title |
Echocardiographic visualization of acute myocardial ischemia--in vitro study. |
| Author |
Chandrasekaran K, Greenleaf JF, Robinson BS, Edwards WD, Seward JB, Tajik AJ. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1986 |
| Abstract |
To evaluate whether myocardial texture changes resulting from acute ischemia can be visualized with satisfactory spatial resolution, short axis compound echo images (CEI) (B-scan) were obtained from 12 excised canine hearts in vitro. Seven had myocardial ischemia produced by open chest ligation of the left anterior descending coronary artery (LAD) for 15-30 min prior to excision. The CEI were constructed by compounding 60 simple linear B-scans. Hearts were sectioned after scanning, and gross morphological changes were recorded. Microscopic comparison between grossly abnormal and normal regions were recorded. The CEI from the ischemic group revealed altered myocardial texture seen as bright coarsely granular echoes in the regions normally perfused by the ligated LAD artery. Corresponding anatomic sections revealed increased redness in these regions. Microscopically these regions revealed interstitial and intercellular edema as compared to the normal regions. Acute myocardial ischemia can be visualized in CEI and these regions have significantly increased backscatter, decreased attenuation, and decreased speed of ultrasound relative to normal regions in the same hearts. Myocardial edema is probably responsible for these changes. |
| Title |
Echoencephalography. |
| Author |
Brinker RA, King DI, Taveras JM. |
| Journal |
Am J Roentgenol Radium Ther Nucl Med |
| Volume |
|
| Year |
1965 |
| Abstract |
Echoencephalography is the term coined by Leksell in 1956 for a new technique by which the position of the midline structures of the brain can be determined. The technique involves passing a beam of pulsed ultrasound into the head of the temporoparietal region and recording the returning echoes. The midline structures, usually the lateral walls of the third ventricle but also the septum pellucidum, pineal gland and interhemispheric fissure, send forth the strongest and most easily recognizable echoes which can then be used to determine the presence or absence of a displacement of these structures. This technique, used increasingly in Europe since 1956, has in the past 2 years come into use in some medical centers in the United States. It is an extremely useful neurologic screening test, as significant as detection of a calcified pineal gland on a frontal skull roentgenogram, and yet obtainable in over 99 per cent of patients. It is the purpose of the authors to describe the technique of echoencephalography and add the results of our clinical trial to the already convincing body of data in the literature indicating the value, efficiency, and accuracy of the procedure.
The determination of the midline echo is of value in all patients, especially those without a calcified pineal body, suspected of having neurologic disease. In almost every case where echoencephalography is desired, routine skull roentgenograms are also obtained at the same time, the former supplementing the latter. Use of the equipment and performance of the test are easily learned, and there is no doubt that neurologists, neurologic surgeons, and radiologists, as well as other specialists, will find it of value. It is useful as a screening method for lateralizing pathology, selecting the appropriate neuroroentgenologic procedure, and following the clinical course of patients. Echoencephalography may also be very valuable in patients with head trauma, especially children, for checking the position of the midline structures on admission and subsequently for detecting any shift that might occur due to the development of subdural hematoma.
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| Title |
Echogenicity of the fetal bowel due to gas accumulation. |
| Author |
Caspi B, Elchalal U, Hagay Z, Hellman Y, Juster A, Manor M. |
| Journal |
J Ultrasound Med |
| Volume |
|
| Year |
1993 |
| Abstract |
No abstract available. |
| Title |
Echographic evaluation of abdominal tumor regression during antineoplastic treatment. |
| Author |
Kobayashi T, Osamutakatani, Hattori N, Kimura K. |
| Journal |
J Clin Ultrasound |
| Volume |
|
| Year |
1974 |
| Abstract |
Twenty patients with malignant abdominal tumors were evaluated by compound contact B-mode ultrasonic scanning. The studies were carried out during and after antineoplastic treatment with chemotherapy, radiation or surgery. Gain and sensitivity settings were kept constant before and after treatment. The changes in echographic findings were correlated with clinical, laboratory and/or autopsy findings. Ultrasound proved to be a very useful and convenient way to evaluate the antitumor effect of various chemotherpeutic agents. Typical echograms are shown to illustrate the method of ultrasonic evaluation. |
| Title |
Echographic visualization of lesions of the living intact human breast. |
| Author |
Wild JJ, Reid JM. |
| Journal |
Cancer Res |
| Volume |
|
| Year |
1954 |
| Abstract |
The purpose of this report is to show that the nature of lesions or tissue abnormalities of the living, intact human breast can be determined by the use of pulsed ultrasound. The study is not necessarily directed toward cancer detection and is not necessarily intended to replace existing technics of detection and diagnosis of breast lesions, but rather is aimed at the more fundamental question of whether or not the histological structure of tissue in general can be determined by ultrasonic technics. The breast was selected as a convenient accessible organ for direct studies on the patient and because of the certainty of obtaining a quick microscopic diagnosis of the lesions. This study is one of the steps toward the examination of less accessible sites. |
| Title |
Echoicity of whole blood. |
| Author |
Yuan YW, Shung KK. |
| Journal |
J Ultrasound Med |
| Volume |
|
| Year |
1989 |
| Abstract |
A clear relationship was found to exist when the echoicity of whole blood under different flow conditions was determined and related to its corresponding ultrasonic backscattering properties. The results indicate that the echoicity of whole blood is shear rate and species dependent. Echoicity of porcine whole blood was found to decrease as the shear rate was increased, whereas the echoicity of bovine whole blood was found to be shear rate independent. At the same shear rate and hematocrit, the echoicity of human and porcine whole blood was found to be higher than that of bovine whole blood. These observations can be readily understood when red cell aggregation is considered. In imaging porcine whole blood under steady laminar flow, under certain conditions a hypoechoic region was observed to appear near the center of the flow conduit. The behavior of this hypoechoic region and the mechanisms responsible for its appearance are not entirely clear at present. |
| Title |
Edge detection in ultrasound speckle noise. |
| Author |
Czerwinski RN, Jones DL, O'Brien WD Jr. |
| Journal |
Proc IEEE Conf Image Process |
| Volume |
|
| Year |
1994 |
| Abstract |
Presents a statistical approach to edge detection in ultrasound speckle, and uses actual noise statistics to derive an expression for an optimal detection rule. The authors compute the optimal detector for the special case of uncorrelated speckle, and an approximation to the optimal detector for the case when signal-to-noise ratio (SNR) is high. They also discuss a simple sub-optimal detection scheme, and show that its performance is close to that of the optimal uncorrelated speckle detection rule, and surpasses that of the high-SNR approximation except in the case of extremely high SNR, in which case they both perform equally well. |
| Title |
Edge detection in ultrasound speckle noise. |
| Author |
Czerwinski RN, Jones DL, O'Brien WD Jr. |
| Journal |
Proc IEEE Conf Image Process |
| Volume |
|
| Year |
1994 |
| Abstract |
Presents a statistical approach to edge detection in ultrasound speckle, and uses actual noise statistics to derive an expression for an optimal detection rule. The authors compute the optimal detector for the special case of uncorrelated speckle, and an approximation to the optimal detector for the case when signal-to-noise ratio (SNR) is high. They also discuss a simple sub-optimal detection scheme, and show that its performance is close to that of the optimal uncorrelated speckle detection rule, and surpasses that of the high-SNR approximation except in the case of extremely high SNR, in which case they both perform equally well. |
| Title |
Efeito cronotropico negativo em coracao de ratos apos a aplicacao du ultrassom de alta potencia |
| Author |
Coiado OC, Buiochi EB, Costa ET, Bassani RA, O'Brien WD Jr. |
| Journal |
XXIII Congresso Brasileiro em Engenharia Biomedica |
| Volume |
|
| Year |
2012 |
| Abstract |
High-power ultrasound (HPUS) exposure
of rat hearts may affect cardiac function. In this
article, we report that thoracic application of HPUS
(1 MHz) caused negative chronotropic effect on
anesthetized rats, but did not produce gross
morphological alterations of lungs and myocardium.
The chronotropic effect was achieved by using a
specific stimulation pattern in which the pulse
repetition frequency was progressively decreased.
The magnitude of the chronotropic effect depended
on the transducer used. Results suggest that care
must be taken during therapeutic use of HPUS, due
to its potential effects on heart rate. |
| Title |
Effect of 2 MHz ultrasound on DNA, RNA and protein synthesis in Pisum sativum root meristem cells. |
| Author |
Miller MW, Ciaravino V, Allen D, Jensen S. |
| Journal |
Int J Radiat Biol Relat Stud Phys Chem Med |
| Volume |
|
| Year |
1976 |
| Abstract |
The amounts of DNA, RNA and protein synthesis were determined in Pisum sativum root meristem cells at various times after a 1 min exposure to 1 MHz ultrasound at a power density of 30 W/cm2. Immediate depressions in all three macromolecular syntheses occurred after sonication, followed by an apparent recovery several hours later. These events appear to correlate in time with the subsequent reduction and recovery in mitotic index in Pisum sativum root meristem cells exposed to 2 MHz ultrasound. |
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