scholarly journals Measurement of Regional Cerebral pH in Human Subjects Using Continuous Inhalation of 11CO2 and Positron Emission Tomography

1984 ◽  
Vol 4 (3) ◽  
pp. 458-465 ◽  
Author(s):  
David J. Brooks ◽  
Adriaan A. Lammertsma ◽  
Ronald P. Beaney ◽  
Klaus L. Leenders ◽  
Peter D. Buckingham ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Human Subjects ◽  
Compartment Model ◽  
Emission Tomography ◽  
Inhalation Technique ◽  
Positron Emission ◽  
Brain Ph ◽  
Normal Human ◽  
Uptake Data ◽  
Arterial Plasma

The cerebral pH of four normal human subjects has been measured using continuous inhalation of 11CO2 and positron emission tomography (PET). 11CO2 was administered to each subject at a constant rate for 15 min, during which time serial arterial plasma 11C levels were determined and serial 11C cerebral uptake PET scans were performed at a fixed axial tomographic level. 11C uptake kinetics were analysed using a three-compartment model. Rate constants have been estimated for the free exchange of 11CO2 between plasma and cerebral compartments for each subject, and their cerebral pH calculated. Whole brain pH values ranged from 6.96 to 7.05, and no significant pH difference between regions containing predominantly grey or white matter was noted. Best fits to 11C uptake data were achieved by effectively neglecting the metabolic fixation of 11C by cerebral tissue. The purpose of this study was to test the feasibility of pH measurement using the 11CO2 continuous inhalation technique. It is concluded from the results and the error analysis that continuous 11CO2 inhalation combined with PET is potentially a simple and useful method for determining regional cerebral pH.

scholarly journals Glucose Transport across the Blood—Brain Barrier in Normal Human Subjects and Patients with Cerebral Tumours Studied Using [11C]3-O-Methyl-D-Glucose and Positron Emission Tomography

1986 ◽  
Vol 6 (2) ◽  
pp. 230-239 ◽  
Author(s):  
D. J. Brooks ◽  
R. P. Beaney ◽  
A. A. Lammertsma ◽  
S. Herold ◽  
D. R. Turton ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Glucose Transport ◽  
Human Subjects ◽  
Competitive Inhibitor ◽  
Emission Tomography ◽  
Normal Brain ◽  
Cerebral Tumours ◽  
Positron Emission ◽  
Regional Cerebral Blood Volume ◽  
Normal Human

The kinetics of the regional cerebral uptake of [11C]3- O-methyl-d-glucose ([11C]MeG), a competitive inhibitor of d-glucose transport, have been studied in normal human subjects and patients with cerebral tumours using positron emission tomography (PET). Concomitant measurement of regional cerebral blood volume and blood flow enabled corrections for the contribution of intravascular tracer signal in PET scans to be carried out and regional unidirectional cerebral [11C]MeG extractions to be determined. A three-compartment model containing an arterial plasma and two cerebral compartments was required to produce satisfactory fits to experimental regional cerebral [11C]MeG uptake data. Under fasting, resting conditions, normal controls had mean unidirectional whole-brain, cortical, and white matter [11C]MeG extractions of 14, 13, and 17%, respectively. Mean values of k1 and k2, first-order rate constants describing forward and back transport, respectively, of tracer into the first cerebral compartment, were similar for [11C]MeG and [18F]2-fluoro-2-deoxy-d-glucose (18FDG), a second competitive inhibitor of d-glucose transport, k3, a rate constant describing FDG phosphorylation, was 20 times higher for cortical FDG uptake than the k3 fitted for [11C]MeG cortical uptake. Glioma [11C]MeG extractions ranged from normal levels of 12% to raised levels of 30%. Transport of [11C]MeG in and out of contralateral cortical tissue was significantly depressed in patients with gliomas. It is concluded that under fasting, resting conditions, regional cerebral glucose extraction remains relatively uniform throughout normal brain tissue. Gliomas, however, may have raised levels of glucose extraction. The nature of the second cerebral compartment required to describe [11C]MeG uptake is unclear, but it could represent either a useless phosphorylation–dephosphorylation cycle or nonspecific tracer uptake by a cerebral sub-compartment.

Serotonin modulation of cerebral glucose metabolism measured with positron emission tomography (PET) in human subjects

Synapse ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Gwenn S. Smith ◽  
Yilong Ma ◽  
Vijay Dhawan ◽  
Handan Gunduz ◽  
Maren Carbon ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Glucose Metabolism ◽  
Human Subjects ◽  
Cerebral Glucose Metabolism ◽  
Emission Tomography ◽  
Positron Emission

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.

scholarly journals Measurement of Regional Cerebral Blood Flow with Positron Emission Tomography: A Comparison of [15O]Water to [11C]Butanol with Distributed-Parameter and Compartmental Models

1993 ◽  
Vol 13 (5) ◽  
pp. 733-747 ◽  
Author(s):  
Robert P. Quarles ◽  
Mark A. Mintun ◽  
Kenneth B. Larson ◽  
Joanne Markham ◽  
Ann Mary MacLeod ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Visual Stimulation ◽  
Human Subjects ◽  
Volume Of Distribution ◽  
Emission Tomography ◽  
Low Flow ◽  
Distributed Parameter ◽  
Positron Emission ◽  
The One

To further our understanding of the best way to measure regional CBF with positron emission tomography (PET), we directly compared two candidate tracers ([15O]water and [11C]butanol, administered intravenously) and two popular implementations of the one-compartment (IC) model: the autoradiographic implementation representing a single PET measurement of tissue radioactivity over 1 min and a dynamic implementation representing a sequence of measurements of tissue radioactivity over 200 s. We also examined the feasibility of implementing a more realistic, and thus more complex, distributed-parameter (DP) model by assigning fixed values for all of its parameters other than CBF and tracer volume of distribution ( Vd), a requirement imposed by the low temporal resolution and statistical quality of PET data. The studies were performed in three normal adult human subjects during paired rest and visual stimulation. In each subject seven regions of interest (ROIs) were selected, one of which was the primary visual cortex. The corresponding ROI were anatomically equivalent in the three subjects. Regional CBF, Vd, tracer arrival delay, and dispersion were estimated for the dynamic data curves. A total of 252 parameter sets were estimated. With [11C]butanol both implementations of the IC model provided similar results ( r = 0.97). Flows estimated using the 1C models were lower (p < 0.01) with [15O]water than with [11C]butanol. In comparison with the IC model, the constrained version of the DP used in these studies performed inadequately, overestimating high flow and underestimating low flow with both tracers, possibly as the result of the necessity of assigning fixed values for all of its parameters other than CBF and Vd.

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