Investigation and Development of Ultrasonic Blood Flow Measurement Techniques
Author : K. Avanessian
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Page : 0 pages
File Size : 25,41 MB
Release : 1980
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Author : K. Avanessian
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Page : 0 pages
File Size : 25,41 MB
Release : 1980
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Author : K. Avanessian-Bash-Ghaleh
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Page : pages
File Size : 17,46 MB
Release : 1980
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Page : 5 pages
File Size : 49,22 MB
Release : 2001
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Ultrasonic contrast specific blood flow measurement techniques offer new opportunities to assess blood flow information based on evaluation of time-intensity curves (TICs). Such curves are measured to estimate concentration of the microbubbles in the blood pool. Based on the indicator-dilution theory, hemodynamic parameters such as the volume flow rate can be directly related to the time constant estimated from the TICs. In this paper, the applicability of the indicator-dilution theory is studied with an in vitro experiment setup. Moreover, the linear system assumption of the blood mixing mechanism is also tested. Several flow phantoms are constructed and a self-made, albumin based contrast agent is used. The TIC is measured by using B-mode images obtained from a commercial ultrasound system. It is found that with a bolus injection and a single mixing chamber, the estimated time constants agree with the theory despite that the effective mixing volume may be smaller than the actual mixing chamber volume in some conditions. More importantly, discrepancy also exists with a prolonged injection and/or two mixing chambers with cascade connection. In other words, the linear system assumption is still questionable even under the controlled in vitro experimental conditions. Potential sources of the discrepancy require further investigation in order to develop contrast specific quantitative blood flow measurement techniques.
Author : Ray W. Ware
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Page : 104 pages
File Size : 32,74 MB
Release : 1968
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Page : 776 pages
File Size : 32,6 MB
Release : 1989
Category : Medicine
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Author : Birgit Arabin
Publisher : Springer Science & Business Media
Page : 157 pages
File Size : 25,94 MB
Release : 2012-12-06
Category : Medical
ISBN : 3642749917
Doppler ultrasound is a hot topic at the present time. This is because studies of the uteroplacental and fetal circulation give fundamental information as to the physiology or pathology of placental function and the response of the fetal circulation to hypoxaemia. Dr. Arabin's clinical studies which are described in this book are an important contribution to knowledge in this field and will be of enormous interest not only to researches but also to clini cians interested in learning how this latest technology can be integrated into their clinical practice. London STUART CAMPBELL Foreword Although only three decades old, the field of perinatal medicine is marked by continuous new advances. Ultrasound diagnostic techniques comprise an important element of this new field. Dr. Arabin has taken the initiative to investigate the functional-diagnostic aspects of ultrasound. Among other things, she has further developed and refined the concept of "oxygen-con serving adaptation of fetal circulation" which originated in the Department of Obstetrics and Gynecology at the Neukolln Hospital Center in 1966. She thus has been able to show that the most reliable Doppler blood flow meas urement predictors of a high risk to the fetus are (1) a decrease in the flow volume of the descending thoracic aorta and the umbilical artery and (2) an increase in the flow volume of the common carotid arteries.
Author : Julie Elizabeth Paynter
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Page : 210 pages
File Size : 10,77 MB
Release : 1981
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Page : 1136 pages
File Size : 24,17 MB
Release : 1986
Category : Disabled veterans
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Author : Lovelace Medical Foundation. Research Symposium
Publisher : Elsevier Publishing Company
Page : 566 pages
File Size : 27,45 MB
Release : 1985
Category : Medical
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Author : Maria da Graça Cristo dos Santos Lopes Ruano
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Page : 378 pages
File Size : 27,13 MB
Release : 1992
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