scholarly journals A Determination of the Regional Brain/Blood Partition Coefficient of Water Using Dynamic Positron Emission Tomography

1989 ◽  
Vol 9 (6) ◽  
pp. 874-885 ◽  
Author(s):  
Hidehiro Iida ◽  
Iwao Kanno ◽  
Shuichi Miura ◽  
Matsutaro Murakami ◽  
Kazuhiro Takahashi ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Partition Coefficient ◽  
Insular Cortex ◽  
Compartment Model ◽  
The Other ◽  
Emission Tomography ◽  
Dynamic Positron Emission Tomography ◽  
Single Compartment ◽  
Content Ratio ◽  
Positron Emission

In order to investigate the validity of the single compartment model in measuring CBF with the use of 15O-labeled water (H215O), dynamic positron emission tomography (PET) was performed following bolus injection of H215O. Careful attention was paid to accuracy in the measurement system (especially for the input function). In the region of the putamen, which includes the smallest mixture of gray and white matters in addition to the smallest contamination of cerebrospinal fluid (CSF) spaces, the partition coefficient obtained was 0.88 ± 0.06 (ml/g). The discrepancy from the prediction estimated from the brain/blood water content ratio was only 7%. This finding suggests that there is no more complicated model than the usual single compartment one to describe the physiological behaviour of 15O water. On the other hand, in the other cortical regions, the discrepancy was larger (e.g., about 12% for the insular cortex and 26% for the frontal cortex) than in the region of the putamen, and a significant fit–interval dependence was observed in the calculated parameters. These observations suggest a significant effect of tissue heterogeneity and/or contamination with nonperfusable spaces in actual clinical PET data.

scholarly journals A Two-Compartment Description and Kinetic Procedure for Measuring Regional Cerebral [11C]Nomifensine Uptake Using Positron Emission Tomography

1990 ◽  
Vol 10 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Eric Salmon ◽  
David J. Brooks ◽  
Klaus L. Leenders ◽  
David R. Turton ◽  
Sue P. Hume ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Partition Coefficient ◽  
Cell Activity ◽  
Compartment Model ◽  
Input Function ◽  
Volume Of Distribution ◽  
Red Cells ◽  
Emission Tomography ◽  
Binding Potential ◽  
Positron Emission

S-[11C]Nomifensine ( S-[11C]NMF) is a positron-emitting tracer suitable for positron emission tomography, which binds to both dopaminergic and noradrenergic reuptake sites in the striatum and the thalamus. Modelling of the cerebral distribution of this drug has been hampered by the rapid appearance of glucuronide metabolites in the plasma, which do not cross the blood–brain barrier. To date, [11C]NMF uptake has simply been expressed as regional versus nonspecific cerebellar activity ratios. We have calculated a “free” NMF input curve from red cell activity curves, using the fact that the free drug rapidly equilibrates between red cells and plasma, while glucuronides do not enter red cells. With this free [11C]NMF input function, all regional cerebral uptake curves could be fitted to a conventional two-compartment model, defining tracer distribution in terms of [11C]NMF regional volume of distribution. Assuming that the cerebellar volume of distribution of [11C]NMF represents the nonspecific volume of distribution of the tracer in striatum and thalamus, we have calculated an equilibrium partition coefficient for [11C]NMF between freely exchanging specific and nonspecific compartments in these regions, representing its “binding potential” to dopaminergic or noradrenergic uptake sites (or complexes). This partition coefficient was lower in the striatum when the racemate rather than the active S-enantiomer of [11C]NMF was administered. In the striatum of patients suffering from Parkinson's disease and multiple-system atrophy, the specific compartmentation of S-[11C]NMF was significantly decreased compared with that of age-matched volunteers.

scholarly journals A new noninvasive quantification of renal blood flow with N-13 ammonia, dynamic positron emission tomography, and a two-compartment model.

1992 ◽  
Vol 3 (6) ◽  
pp. 1295-1306
Author(s):  
B C Chen ◽  
G Germano ◽  
S C Huang ◽  
R A Hawkins ◽  
H W Hansen ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Pet Imaging ◽  
Renal Cortex ◽  
Compartment Model ◽  
Regions Of Interest ◽  
Emission Tomography ◽  
Dynamic Positron Emission Tomography ◽  
Positron Emission ◽  
Two Compartment Model

In order to determine if dynamic positron emission tomography (PET) and N-13 ammonia can be used to quantitate regional RBF (rRBF) noninvasively, six anesthetized dogs were examined with PET imaging after an iv bolus administration of 5 mCi of N-13 ammonia. Renal time activity curves and the arterial input function were derived from regions of interest drawn over the renal cortex and abdominal aorta, respectively. For calculation of rRBF, less than 120 s of the initial data were used to minimize contamination by plasma metabolites of N-13 radioactivity. rRBF was quantitated with a two-compartment model, and the results were compared with simultaneously acquired microsphere blood flow measurement. Fourteen experiments were performed in six dogs, and four regions of interest on renal cortex were selected on each PET image. RBF derived from dynamic PET imaging with N-13 ammonia was linearly related to microsphere (MS) values (rRBF = 1.06 x MS - 0.17; r = 0.91). Mean rRBF in the canine experiments was 4.0 mL/min/g. The results indicate that dynamic N-13 ammonia renal PET can provide noninvasively quantitative rRBF.

scholarly journals Quantitation of Translocator Protein Binding in Human Brain with the Novel Radioligand [18F]-FEPPA and Positron Emission Tomography

2011 ◽  
Vol 31 (8) ◽  
pp. 1807-1816 ◽  
Author(s):  
Pablo M Rusjan ◽  
Alan A Wilson ◽  
Peter M Bloomfield ◽  
Irina Vitcu ◽  
Jeffrey H Meyer ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Human Brain ◽  
Specific Binding ◽  
Compartment Model ◽  
Distribution Volume ◽  
Translocator Protein ◽  
Emission Tomography ◽  
Binding Potential ◽  
Specific Distribution ◽  
Positron Emission

This article describes the kinetic modeling of [18F]-FEPPA binding to translocator protein 18 kDa in the human brain using high-resolution research tomograph (HRRT) positron emission tomography. Positron emission tomography scans were performed in 12 healthy volunteers for 180 minutes. A two-tissue compartment model (2-CM) provided, with no exception, better fits to the data than a one-tissue model. Estimates of total distribution volume ( VT), specific distribution volume ( VS), and binding potential ( BPND) demonstrated very good identifiability (based on coefficient of variation ( COV)) for all the regions of interest (ROIs) in the gray matter ( COV VT < 7%, COV VS < 8%, COV BPND < 11%). Reduction of the length of the scan to 2 hours is feasible as VS and VT showed only a small bias (6% and 7.5%, respectively). Monte Carlo simulations showed that, even under conditions of a 500% increase in specific binding, the identifiability of VT and VS was still very good with COV<10%, across high-uptake ROIs. The excellent identifiability of VT values obtained from an unconstrained 2-CM with data from a 2-hour scan support the use of VT as an appropriate and feasible outcome measure for [18F]-FEPPA.

Sign in / Sign up

Export Citation Format

Share Document