Indicator dilution measurement of mean transit time and flow in a straight tube

Lane, David A.; Sirs, John A.

doi:10.1088/0022-3735/7/1/014

Cited by 18 publications

(18 citation statements)

References 4 publications

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“…5 do not fall on the line ut/x = 1 0, is also at variance with accepted indicator dilution theory. This discrepancy, of the indicator dilution theory in laminar flow, was noted by Bate & Sirs (1971) and Bate et al (1973) and has recently been given a theoretical basis by Lane & Sirs (1974). This investigation is supported by a grant from the Wellcome Trust.…”

Section: Discussionmentioning

confidence: 68%

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The dispersion of solutes during blood flow through a straight tube

Lane¹,

Sirs²

1974

The Journal of Physiology

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SUMMARY1. The dispersion of solutes in plasma and blood has been studied by observing the clearance at a point down-stream of a bolus of labelled solution by the steady flow of unlabeled solution.2. With a low molecular weight solute the clearance curve is qualitatively similar in 2N-KCI solution, plasma and whole blood.3. The dispersion of a high molecular weight protein, [131I]HSA, in plasma is dominated by the velocity profile of the flow.4. The clearance curves for HSA in whole blood are similar to those of plasma, except that the red blood cells speed the clearance of protein in the tail region of the curve.5. An analysis of the data suggests that the dispersion of solutes during blood flow through a straight tube can be attributed to the combined effects of solute diffusion and laminar convection. There is no evidence that induced motion of the erythrocytes produces significant mixing, in the bulk of the flow.

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Section: Discussionmentioning

confidence: 68%

“…Under well mixed conditions, such as pertain when diffusion predominates in determining the dispersion, the value of t is 4d. As laminar convection progressively becomes the determining factor, t becomes larger (Lane & Sirs, 1974).…”

Section: Resultsmentioning

confidence: 99%

The dispersion of solutes during blood flow through a straight tube

Lane¹,

Sirs²

1974

The Journal of Physiology

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“…7 Some other authors have also discussed problematic aspects, mostly by use of flow pipe models. [8][9][10][11][12][13][14] The IDT has also been formulated by use of concepts borrowed from the theory of linear ͑stable͒ systems. 2,3,7,15 The use of such a formulation does not, however, demonstrate the validity of the IDT, especially not for all kinds of detectors and labeling processes.…”

Section: Discussionmentioning

confidence: 99%

Is the indicator dilution theory really the adequate base of many blood flow measurement techniques?

Doriot

Dorsaz

et al. 1997

Medical Physics

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The indicator dilution theory is the underlying model of many blood flow measurement techniques used daily in hospitals, for instance in cardiac catheterization laboratories. The basic version of this theory applies to a "stationary" flow system with one inlet and one outlet, into which a small amount M of indicator is injected "suddenly" at time t = 0 at the inlet. The quintessence of the theory consists in three equations, which themselves result from some apparently simple assumptions about the considered flow systems. The first equation states that the (constant) flow Q through the system can be calculated by use of the known amount of indicator, M, and of the indicator concentration-time curve c(t) recorded at the outlet. The second one allows the calculation of the "mean transit time" t* of fluid and indicator particles through the system from the curve c(t). The third equation, V = Qt*, yields the system volume V. It is generally believed that these three equations would be absolutely valid if the assumptions of the theory could be perfectly fulfilled. We show, by considering a simple model, that all three equations are actually incorrect for most flow systems when the detector used to record the curve c(t) is of the "trans-illumination" type, as is the case for instance in dye dilution methods and in many angiographic or CT techniques. A further consequence is that t*, which is truly the "center of mass" of the concentration-time curve c(t), does not have the well known property of being the adequate parameter for flow determinations. Many flow measurement techniques thus appear to have no theoretical base.

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“…The random walk equation and the probability density function are based on the kinetics of the tracer particles. The theory of the distribution of the velocity (velocity profile) of tracer particles has been considered by Taylor (22), Caro (5) and Lane et al (12,13). The observations and the theoretical formulations showed that due to the dispersion of the tracer flowing through different simplified models the velocity profile becomes parabolic, as for the streamline flow of a Newtonian fluid.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Assessment of Cardiac Blood Pools in Radiocardiography by Various Indicator Dilution Models

Olkkonen¹,

Im²

1977

Nuklearmedizin

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SummaryHeart blood pools were evaluated by different indicator dilution models from single detector 113mIn radiocardiographic measurements on healthy subjects. It appeared that generally accepted mathematical expressions based on the nth moments of the radiocardiographic dilution curve overestimate the heart volumes by 30–40%. The study suggests that the indicator dispersion within the heart chambers is an dilution process, which ought to be included in the radiocardiographic models. Dispersion models based on the random walk equation, probability density function and the gamma variate model produced consistent heart volumes. The suitability of the dispersion models for clinical routine use is discussed briefly.

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Indicator dilution measurement of mean transit time and flow in a straight tube

Cited by 18 publications

References 4 publications

The dispersion of solutes during blood flow through a straight tube

The dispersion of solutes during blood flow through a straight tube

Is the indicator dilution theory really the adequate base of many blood flow measurement techniques?

Assessment of Cardiac Blood Pools in Radiocardiography by Various Indicator Dilution Models

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