Determination of transit time in the human jejunum by the single-injection indicator-dilution technic

1968 ◽  
Vol 13 (3) ◽  
pp. 222-233 ◽  
Author(s):  
M. A. Barreiro ◽  
R. D. McKenna ◽  
I. T. Beck
Keyword(s):  
Transit Time ◽  
Single Injection ◽  
Indicator Dilution

scholarly journals Simulating a Ground Truth for Transit Time Analysis of Indicator Dilution Curves

2020 ◽  
Vol 6 (3) ◽  
pp. 268-271
Author(s):  
Michael Reiß ◽  
Ady Naber ◽  
Werner Nahm
Keyword(s):  
Transit Time ◽  
Sampling Rate ◽  
Ground Truth ◽  
Indicator Dilution ◽  
Cross Sectional ◽  
In Vivo Measurements ◽  
Multiple Indicator Dilution ◽  
Transit Times ◽  
Dilution Curves

AbstractTransit times of a bolus through an organ can provide valuable information for researchers, technicians and clinicians. Therefore, an indicator is injected and the temporal propagation is monitored at two distinct locations. The transit time extracted from two indicator dilution curves can be used to calculate for example blood flow and thus provide the surgeon with important diagnostic information. However, the performance of methods to determine the transit time Δt cannot be assessed quantitatively due to the lack of a sufficient and trustworthy ground truth derived from in vivo measurements. Therefore, we propose a method to obtain an in silico generated dataset of differently subsampled indicator dilution curves with a ground truth of the transit time. This method allows variations on shape, sampling rate and noise while being accurate and easily configurable. COMSOL Multiphysics is used to simulate a laminar flow through a pipe containing blood analogue. The indicator is modelled as a rectangular function of concentration in a segment of the pipe. Afterwards, a flow is applied and the rectangular function will be diluted. Shape varying dilution curves are obtained by discrete-time measurement of the average dye concentration over different cross-sectional areas of the pipe. One dataset is obtained by duplicating one curve followed by subsampling, delaying and applying noise. Multiple indicator dilution curves were simulated, which are qualitatively matching in vivo measurements. The curves temporal resolution, delay and noise level can be chosen according to the requirements of the field of research. Various datasets, each containing two corresponding dilution curves with an existing ground truth transit time, are now available. With additional knowledge or assumptions regarding the detection-specific transfer function, realistic signal characteristics can be simulated. The accuracy of methods for the assessment of Δt can now be quantitatively compared and their sensitivity to noise evaluated.

Physiological parameters of indicator dilution curves

1977 ◽  
Vol 233 (3) ◽  
pp. H350-H355
Author(s):  
L. D. Homer ◽  
A. Small
Keyword(s):  
Cardiac Output ◽  
Satisfactory Agreement ◽  
Single Injection ◽  
Time Lag ◽  
Volume Of Distribution ◽  
Physiological Parameters ◽  
Indicator Dilution ◽  
Diethylenetriaminepentaacetic Acid ◽  
Alternative Techniques ◽  
Dilution Curves

A model incorporating the effects of recirculation time lag, cardiac output, clearance, volume of distribution, and the variance of the distribution of recirculation times is applied to the analysis of indicator dilution curves. Experiments on dogs with use of radioactively labeled diethylenetriaminepentaacetic acid were done to evaluate the model. This five-parameter model can be fitted to data obtained during the period from less than 1 min to 3 h after a single injection of indicator. Estimates of cardiac output and clearance are in satisfactory agreement with estimates obtained by alternative techniques. Estimates of the time lag and volume of distribution are of physiologically plausible magnitude. The variance of the distribution of recirculation times is a new parameter, of which the possible usefulness to physiologists is discussed.

scholarly journals Blood Flow to Hindquarters of Steers Measured by Transit Time Ultrasound and Indicator Dilution

1987 ◽  
Vol 70 (7) ◽  
pp. 1385-1390 ◽  
Author(s):  
J.H. Eisemann ◽  
G.B. Huntington ◽  
C.L. Ferrell
Keyword(s):  
Blood Flow ◽  
Transit Time ◽  
Indicator Dilution

scholarly journals Simultaneous determination of parabens and inorganic anions in cosmetics by a two-dimensional ultrahigh-performance liquid chromatography-ion chromatography valve-switching method

RSC Advances ◽  
2017 ◽  
Vol 7 (52) ◽  
pp. 32769-32776 ◽  
Author(s):  
Feng-Lian Wang ◽  
Yong-Gang Zhao ◽  
Nadeem Muhammad ◽  
Shu-Chao Wu ◽  
Yan Zhu
Keyword(s):  
Simultaneous Determination ◽  
Single Injection ◽  
Inorganic Anions ◽  
Two Dimensional ◽  
Switching System ◽  
System P ◽  
Ultrahigh Performance Liquid Chromatography ◽  
Switching Method ◽  
Valve Switching

Simultaneous determination of parabens and inorganic anions in cosmetics in a single injection was obtained in a two-dimensional UHPLC-IC valve switching system.

Isolation of radioactive iodothyronines for kinetic studies: a comparison of two methods

1982 ◽  
Vol 99 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Jens Faber ◽  
lb Bo Lumholtz ◽  
Carsten Kirkegaard ◽  
Kaj Siersbæk-Nielsen ◽  
Thorkild Friis
Keyword(s):  
Radioactive Iodine ◽  
Single Injection ◽  
Kinetic Studies ◽  
Acid Precipitation ◽  
Relative Difference ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Minor Degree ◽  
A Minor

Abstract. A method based on the principle of gel separation followed by antibody extraction (GSAE) has been developed for isolation of radioactive thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), 3,3'-diiodothyronine (3,3'-T2), 3',5'-diiodothyronine (3',5'-T2) and 3'-monoiodothyronine (3'-T1) in serum. This method was used for the estimation of the metabolic clearance rate (MCR) of the iodothyronines using the single injection, non-compartmental approach, and was compared to the conventional trichloroacetic acid precipitation/ethanol extraction (TCA-E) technique. The GSAE method excluded the co-determination of radioactive iodine and iodoproteins, whereas the co-determination of radiolabelled daughter iodothyronines was found negligible. The relative difference of duplicate estimations of MCR was approximately 10%. Using the TCA-E method for isolation of tracer, the MCR of T4, T3 and rT3 was underestimated to a minor degree (20%), whereas the MCRs of 3,3'-T2, 3',5'-T2 and 3'-T1 were 20–40% of those estimated by the GSAE method. In conclusion the GSAE method was found suitable for kinetic studies of iodothyronines, whereas the TCA-E method cannot be used for turnover studies of 3,3'-T2, 3',5'-T2 or 3'-T1.

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