A quantitative method for estimating hepatic blood flow using a dual-input single-compartment model

2008 ◽  
Vol 81 (970) ◽  
pp. 790-800 ◽  
Author(s):  
S MIYAZAKI ◽  
K MURASE ◽  
T YOSHIKAWA ◽  
S MORIMOTO ◽  
Y OHNO ◽  
...  
Keyword(s):  
Blood Flow ◽  
Hepatic Blood Flow ◽  
Quantitative Method ◽  
Compartment Model ◽  
Single Compartment ◽  
Single Compartment Model

scholarly journals A Study of the Single Compartment Tracer Kinetic Model for the Measurement of Local Cerebral Blood Flow Using 15O-Water and Positron Emission Tomography

1987 ◽  
Vol 7 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Sanjiv S. Gambhir ◽  
Sung-Cheng Huang ◽  
Randall A. Hawkins ◽  
Michael E. Phelps
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Data Collection ◽  
Human Subjects ◽  
Compartment Model ◽  
Distribution Volume ◽  
Single Compartment ◽  
Positron Emission ◽  
Single Compartment Model ◽  
Collection Time

The effects of varying the data collection time on the calculation of cerebral blood flow and distribution volume via the integrated projection technique were studied in four human subjects. The significance of these results in terms of the limitations of the single compartment model for 15O-water was explored using computer simulations. The simulations helped to account for causes for the variations seen in blood flow and distribution volume as a function of the data collection time. Two different compartmental models were explored for better quantitation of blood flow and distribution volume.

An approach for comparative quantification of myocardial blood flow (0-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT), and metabolism (F 18-FDG-PET)

2001 ◽  
Vol 40 (05) ◽  
pp. 164-171 ◽  
Author(s):  
B. Nowak ◽  
H.-J. Kaiser ◽  
S. Block ◽  
K.-C. Koch ◽  
J. vom Dahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Fdg Pet ◽  
Model Fitting ◽  
Compartment Model ◽  
Left Ventricular ◽  
Short Axis ◽  
New Approach ◽  
Single Compartment Model ◽  
Tissue Fraction

Summary Aim: In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices. Methods: 42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin 5PECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All dato sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, rnidventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (>70% TT-SPECT) were used for comparative quantification. Results: First and second mean global MBF values were 0.85 ml × min-1 × g-1 and 0.84 ml × min-1 × g1, respectively, with a repeatability coefficient of 0.30 ml ÷ min-1 × gl. After sectorization mean MBF_micr was between 0.58 ml × min1 ÷ ml"1 and 0.68 ml × min-1 × ml"1 in well perfused areas. Corresponding TT-SPECT values ranged from 83 % to 91 %, and FDG-PET values from 91 % to 103%. All procedures yielded higher values for the lateral than the septal regions. Conclusion: Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

A single compartment model of pacemaking in dissasociated Substantia nigra neurons

2013 ◽  
Vol 35 (3) ◽  
pp. 295-316 ◽  
Author(s):  
Febe Francis ◽  
Míriam R. García ◽  
Richard H. Middleton
Keyword(s):  
Substantia Nigra ◽  
Compartment Model ◽  
Single Compartment ◽  
Single Compartment Model

scholarly journals Quantitative analysis of flux along the gluconeogenic, glycolytic and pentose phosphate pathways under reducing conditions in hepatocytes isolated from fed rats

1983 ◽  
Vol 212 (3) ◽  
pp. 585-598 ◽  
Author(s):  
J M Crawford ◽  
J J Blum
Keyword(s):  
Compartment Model ◽  
Pentose Phosphate ◽  
Improved Method ◽  
Single Compartment ◽  
Reducing Conditions ◽  
Single Compartment Model ◽  
Net Flux ◽  
Pentose Phosphate Pathways ◽  
Fructose 1,6 Bisphosphate ◽  
Hexose Phosphates

Hepatocytes were isolated from the livers of fed rats and incubated with a mixture of glucose (10 mM), ribose (1 mM), mannose (4 mM), glycerol (3 mM), acetate (1.25 mM), and ethanol (5 mM) with one substrate labelled with 14C in any given incubation. Incorporation of label into CO2, glucose, glycogen, lipid glycerol and fatty acids, acetate and C-1 of glucose was measured at 20 and 40 min after the start of the incubation. The data (about 48 measurements for each interval) were used in conjunction with a single-compartment model of the reactions of the gluconeogenic, glycolytic and pentose phosphate pathways and a simplified model of the relevant mitochondrial reactions. An improved method of computer analysis of the equations describing the flow of label through each carbon atom of each metabolite under steady-state conditions was used to compute values for the 34 independent flux parameters in this model. A good fit to the data was obtained, thereby permitting good estimates of most of the fluxes in the pathways under consideration. The data show that: net flux above the level of the triose phosphates is gluconeogenic; label in the hexose phosphates is fully equilibrated by the second 20 min interval; the triose phosphate isomerase step does not equilibrate label between the triose phosphates; substrate cycles are operating at the glucose-glucose 6-phosphate, fructose 6-phosphate-fructose 1,6-bisphosphate and phosphoenolpyruvate-pyruvate-oxaloacetate cycles; and, although net flux through the enzymes catalysing the non-oxidative steps of the pentose phosphate pathway is small, bidirectional fluxes are large.

Influence of nonlinearities on estimates of respiratory mechanics using multilinear regression analysis

1994 ◽  
Vol 77 (3) ◽  
pp. 1185-1197 ◽  
Author(s):  
S. Kano ◽  
C. J. Lanteri ◽  
A. W. Duncan ◽  
P. D. Sly
Keyword(s):  
Respiratory System ◽  
Respiratory Mechanics ◽  
Compartment Model ◽  
Multilinear Regression ◽  
Multilinear Regression Analysis ◽  
Single Compartment ◽  
Dependent Component ◽  
Single Compartment Model ◽  
Volume Controlled ◽  
Pressure Controlled

To investigate the influence of nonlinearities on estimates of respiratory mechanics, differing patterns of mechanical ventilation patterns were analyzed from 8 puppies and 14 children. Respiratory mechanics were calculated using multiple linear regression to fit a linear single-compartment model, a volume-dependent single-compartment model (VDSCM), and a flow-dependent single-compartment model. The ratio of the compliance of the last 20% of the dynamic volume-pressure (V-P) curve to the total compliance (C20/C) and the contribution of a volume-dependent elastance to total elastance [%E2 = E2 (VT)/[(E1 + E2)VT], where E1 + E2 is total elastance, E2 is the volume-dependent component, and VT is tidal volume] were used as the indexes of over-distension. By positioning the dynamic loops on the static V-P curves, ventilation patterns were classified as overdistended or nonoverdistended. In the overdistended group, the C20/C was significantly lower (0.71 +/- 0.10 vs. 0.92 +/- 0.16; P < 0.0001) and %E2 was significantly higher (43.4 +/- 15.0 vs. 0.51 +/- 18.02%, P < 0.0001) than in the nonoverdistended group. The mode of ventilation (pressure controlled vs. volume controlled) and the resistive pressures that resulted in widening of the dynamic V-P loop were found to alter C20/C but not %E2. When the respiratory system was overdistended, i.e., ventilated up to the flattened portion of the V-P curve, the VDSCM gave more accurate estimates of respiratory mechanisms. Furthermore, %E2 calculated from VDSCM is a useful parameter for estimating respiratory system overdistension that is not affected by resistive pressures.

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