A new approach to compartmental analysis

1982 ◽  
Vol 243 (3) ◽  
pp. R424-R432
Author(s):  
M. H. Sherif
Keyword(s):  
Compartmental Analysis ◽  
Indicator Dilution ◽  
Suggested Model ◽  
Compartment Analysis ◽  
New Approach ◽  
Single Compartment ◽  
Novel Approach ◽  
Indicator Dilution Theory ◽  
Traditional Approaches ◽  
Dilution Theory

When recirculation of compounds and/or mixing transients are appreciable, traditional compartment analysis can lead to erroneous results. In this paper, a novel approach that overcomes many of these difficulties is presented. It unifies classical compartment analysis and indicator-dilution theory. It is conceptually simple and can be easily extended to many situations. Several examples for the case of a single compartment demonstrate the superiority of the suggested model to more traditional approaches.

A novel approach to teach the generation of bioelectrical potentials from a descriptive and quantitative perspective

2013 ◽  
Vol 37 (4) ◽  
pp. 327-336 ◽  
Author(s):  
Javier Rodriguez-Falces
Keyword(s):  
Muscle Fiber ◽  
New Method ◽  
Excitation Source ◽  
New Approach ◽  
Electrical Fields ◽  
Novel Approach ◽  
Electrophysiological Signals ◽  
Survey Results ◽  
Traditional Approaches ◽  
Extracellular Potentials

In electrophysiology studies, it is becoming increasingly common to explain experimental observations using both descriptive methods and quantitative approaches. However, some electrophysiological phenomena, such as the generation of extracellular potentials that results from the propagation of the excitation source along the muscle fiber, are difficult to describe and conceptualize. In addition, most traditional approaches aimed at describing extracellular potentials consist of complex mathematical machinery that gives no chance for physical interpretation. The aim of the present study is to present a new method to teach the formation of extracellular potentials around a muscle fiber from both a descriptive and quantitative perspective. The implementation of this method was tested through a written exam and a satisfaction survey. The new method enhanced the ability of students to visualize the generation of bioelectrical potentials. In addition, the new approach improved students' understanding of how changes in the fiber-to-electrode distance and in the shape of the excitation source are translated into changes in the extracellular potential. The survey results show that combining general principles of electrical fields with accurate graphic imagery gives students an intuitive, yet quantitative, feel for electrophysiological signals and enhances their motivation to continue their studies in the biomedical engineering field.

Moment Relations in Indicator Dilution Theory

1987 ◽  
Vol 11 (3-4) ◽  
pp. 239-253
Author(s):  
M. Profant ◽  
K. Vyska ◽  
U. Eckhardt
Keyword(s):  
Indicator Dilution ◽  
Indicator Dilution Theory ◽  
Dilution Theory

Application of indicator dilution theory to time-density curves obtained from dynamic contrast images

2000 ◽  
Author(s):  
Anne V. Clough ◽  
Albert J. Manuel ◽  
Steven T. Haworth ◽  
Christopher A. Dawson
Keyword(s):  
Indicator Dilution ◽  
Indicator Dilution Theory ◽  
Time Density ◽  
Dilution Theory

Feasibility Study of Time-Intensity-Based Blood Flow Measurements Using Deconvolution

2001 ◽  
Vol 23 (2) ◽  
pp. 90-105 ◽  
Author(s):  
Chih-Kuang Yeh ◽  
Sheng-Wuei Wang ◽  
Pai-Chi Li
Keyword(s):  
Blood Flow ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Indicator Dilution ◽  
Time Constants ◽  
Lti System ◽  
Mixing Chamber ◽  
Indicator Dilution Theory ◽  
Deconvolution Techniques ◽  
Dilution Theory

Ultrasonic contrast agents have been used to enhance the acoustic backscattered intensity of blood and to assist the assessment of blood flow parameters. One example is the time-intensity method based on the indicator-dilution theory. In this case, a mixing chamber model can be employed to describe the concentration of the contrast agent as a function of time. By measuring the time intensities at both the input and output of the blood mixing chamber, blood flow information can be obtained if proper deconvolution techniques are applied. Note that most deconvolution techniques assume a linear and time invariant (LTI) system for the mixing of the contrast agent with blood. In this paper, the hypothesis that a blood mixing chamber is an LTI system was tested. Several aspects were studied. One aspect was the linear relationship between the concentration of the contrast agent and the backscattered intensity. The other aspect was the dependence of the derived time constants on the concentration. The concept of an effective mixing volume was also introduced and evaluated. Finally, the input and the output time constants were measured and compared to theory under the LTI assumption. Extensive experiments were performed. Two in vitro flow models were constructed and two contrast agents were used. Results indicated that the LTI assumption does not hold and quantitative flow estimation is generally not possible. Nonetheless, the indicator-dilution theory can still be applied if only relative measurements of the flow rate are required.

Mixing of dye and blood in the canine aorta

1965 ◽  
Vol 20 (5) ◽  
pp. 922-926 ◽  
Author(s):  
L. Jerome Krovetz ◽  
Robert W. Benson
Keyword(s):  
Superior Vena ◽  
Vena Cava ◽  
Indicator Dilution ◽  
Average Difference ◽  
Descending Thoracic Aorta ◽  
Iliac Arteries ◽  
Arterial Sampling ◽  
Indicator Dilution Theory ◽  
Dilution Theory ◽  
Canine Aorta

Paired simultaneous arterial sampling curves from both femoral or iliac arteries of 10 dogs were obtained following injections of indicator in the superior vena cava (SVC), right atrium (RA), left ventricle (LV), aortic root (AR), and descending thoracic aorta (DA). Calculated paired cardiac outputs following injection into the SVC or RA showed an average difference of 5.8% (se 0.97). Injections into the LV were not significantly different in this regard, having an average difference of 6.3% (P < 0.85). Injections into the AR and DA showed progressive increases in the differences of the paired curves, averaging 9.9% and 23.1%, respectively. The degree of aortic mixing of blood and dye appears to be related to the distance available for such mixing. While this cannot be interpreted as evidence for the existence of laminar flow in arteries, the degree of any existing turbulence is inadequate for complete mixing. hemodynamics; turbulence; indicator-dilution theory; branching; arterial branches; cardiac outputs Submitted on October 2, 1964

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