scholarly journals Single-Scan Bayes Estimation of Cerebral Glucose Metabolic Rate: Comparison with Bon-Bades Single-Scan Methods Using DFG Pet Scans in Stroke

1988 ◽  
Vol 8 (3) ◽  
pp. 418-425 ◽  
Author(s):  
P. David Wilson ◽  
Sung-Cheng Huang ◽  
Randall A. Hawkins
Keyword(s):  
Metabolic Rate ◽  
Prior Information ◽  
Normal Population ◽  
Bayes Estimation ◽  
The Other ◽  
Mean Values ◽  
Positron Emission ◽  
Ischemic Tissue ◽  
Monte Carlo Studies ◽  
Pet Scans

Three single-scan (SS) methods are currently available for estimating the local cerebral metabolic rate of glucose (LCMRG) from F-18 deoxyglucose (FDG) positron emission tomography (PET) scan data: SS(SPH), named for Sokoloff, Phelps, and Huang; SS(B), named for Brooks; and SS(H), named for Hutchins and Holden et al. All three of these SS methods make use of prior information in the form of mean values of rate constants from the normal population. We have developed a Bayes estimation (BE) method that uses prior information in the form of rate constant means, variances, and correlations in both the normal and ischemic tissue populations. The BE method selects, based only on the data, whether the LCMRG estimate should be computed using prior information from normal or ischemic tissue. The ability of BE to make this selection gives it an advantage over the other methods. The BE method can be used as a SS method or can use any number of PET scans. We conducted Monte Carlo studies comparing BE as a SS method with the other SS methods, all using a single scan at 60 min. We found SS(H) to be strongly superior to SS(SPH) and SS(B), and we found BE to be definitely superior to SS(H).

scholarly journals Local Interrelationships of Cerebral Oxygen Consumption and Glucose Utilization in Normal Subjects and in Ischemic Stroke Patients: A Positron Tomography Study

1984 ◽  
Vol 4 (2) ◽  
pp. 140-149 ◽  
Author(s):  
J. C. Baron ◽  
D. Rougemont ◽  
F. Soussaline ◽  
P. Bustany ◽  
C. Crouzel ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Kinetic Method ◽  
Normal Subjects ◽  
Combined Method ◽  
Stroke Patients ◽  
Control Subjects ◽  
Cerebral Metabolic Rate ◽  
Positron Emission ◽  
Ischemic Tissue

With the use of positron emission tomography (PET) and the 15O steady-state-[18F]fluorodeoxyglucose combined method, the local interrelationships between the cerebral metabolic rate for oxygen (CMRO2) and the cerebral metabolic rate for glucose (CMRGlc) were investigated in control subjects and in stroke patients. In addition to the classic in vivo autoradiographic approach, a kinetic method was used to measure CMRGlc because it was expected to be more reliable in cerebral ischemia. In control subjects local coupling between CBF, CMRO2, and CMRGlc was confirmed, and acceptable values for the CMRO2/CMRGlc ratio were found; the latter, however, was lower in white matter than in gray. Uncoupling between CMRO2 and CMRGlc was observed in all stroke patients, suggesting that (1) enhanced anaerobic glycolysis occurred both in reperfused recent infarcts and in chronically ischemic tissue, and (2) substrates other than blood-borne glucose were being oxidized at the borders of recent infarcts. However, methodological uncertainties presently make such observations only tentative. Finally, a coupled depression of CMRO2 and CMRGlc was found in the contralateral cerebellum.

Noninvasive Quantification of Regional Myocardial Metabolic Rate of Oxygen by 15 O 2 Inhalation and Positron Emission Tomography

Circulation ◽  
1996 ◽  
Vol 94 (4) ◽  
pp. 808-816 ◽  
Author(s):  
Yusuke Yamamoto ◽  
Ranil de Silva ◽  
Christopher G. Rhodes ◽  
Hidehiro Iida ◽  
Adriaan A. Lammertsma ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Metabolic Rate ◽  
Emission Tomography ◽  
Positron Emission

scholarly journals Effects of Acetazolamide on Cerebral Blood Flow, Blood Volume, and Oxygen Metabolism: A Positron Emission Tomography Study with Healthy Volunteers

2001 ◽  
Vol 21 (12) ◽  
pp. 1472-1479 ◽  
Author(s):  
Hidehiko Okazawa ◽  
Hiroshi Yamauchi ◽  
Kanji Sugimoto ◽  
Hiroshi Toyoda ◽  
Yoshihiko Kishibe ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Metabolic Rate ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Capillary Blood ◽  
Emission Tomography ◽  
Positron Emission ◽  
Capillary Blood Volume

To evaluate changes in cerebral hemodynamics and metabolism induced by acetazolamide in healthy subjects, positron emission tomography studies for measurement of cerebral perfusion and oxygen consumption were performed. Sixteen healthy volunteers underwent positron emission tomography studies with15O-gas and water before and after intravenous administration of acetazolamide. Dynamic positron emission tomography data were acquired after bolus injection of H215O and bolus inhalation of15O2. Cerebral blood flow, metabolic rate of oxygen, and arterial-to-capillary blood volume images were calculated using the three-weighted integral method. The images of cerebral blood volume were calculated using the bolus inhalation technique of C15O. The scans for cerebral blood flow and volume and metabolic rate of oxygen after acetazolamide challenge were performed at 10, 20, and 30 minutes after drug injection. The parametric images obtained under the two conditions at baseline and after acetazolamide administration were compared. The global and regional values for cerebral blood flow and volume and arterial-to-capillary blood volume increased significantly after acetazolamide administration compared with the baseline condition, whereas no difference in metabolic rate of oxygen was observed. Acetazolamide-induced increases in both blood flow and volume in the normal brain occurred as a vasodilatory reaction of functioning vessels. The increase in arterial-to-capillary blood volume made the major contribution to the cerebral blood volume increase, indicating that the raise in cerebral blood flow during the acetazolamide challenge is closely related to arterial-to-capillary vasomotor responsiveness.

scholarly journals PET Scan Perfusion Imaging in the Prader–Willi Syndrome: New Insights into the Psychiatric and Social Disturbances

2010 ◽  
Vol 31 (1) ◽  
pp. 275-282 ◽  
Author(s):  
Carine Mantoulan ◽  
Pierre Payoux ◽  
Gwenaëlle Diene ◽  
Mélanie Glattard ◽  
Bernadette Rogé ◽  
...  
Keyword(s):  
Psychiatric Disorders ◽  
Severe Disabilities ◽  
Brain Regions ◽  
Pet Scan ◽  
Prader Willi Syndrome ◽  
Behavioral Skills ◽  
Positron Emission ◽  
Functional Consequences ◽  
Magnetic Resonance Imaging Mri ◽  
Pet Scans

The Prader–Willi syndrome (PWS), a rare multisystem genetic disease, leads to severe disabilities, such as morbid obesity, endocrine dysfunctions, psychiatric disorders, and social disturbances. We explored the whole brain of patients with PWS to detect abnormalities that might explain the behavioral and social disturbances, as well as the psychiatric disorders of these patients. Nine patients with PWS (six males, three females; mean age 16.4 years) underwent a positron emission tomography (PET) scan with H215O as a tracer to measure regional cerebral blood flow (rCBF). The images were compared with those acquired from nine controls (six males, three females; mean age 21.2 years). A morphologic magnetic resonance imaging (MRI) was also performed in PWS patients, and their cognitive and behavioral skills were assessed with Wechsler Intelligence Scale for Children III and the Child Behavior Check List (CBCL). The MRI images showed no evident anatomic abnormalities, whereas PET scans revealed hypoperfused brain regions in PWS patients compared with controls, particularly in the anterior cingulum and superior temporal regions. We observed a significant relationship ( P<0.05) between rCBF in the hypoperfused regions and CBCL scores. The functional consequences of these perfusion abnormalities in specific brain regions might explain the behavioral and social problems observed in these individuals.

scholarly journals Synthesis, quality control and dosimetry of the radiopharmaceutical 18F-sodium fluoride produced at the Center for Development of Nuclear Technology - CDTN

2010 ◽  
Vol 46 (3) ◽  
pp. 563-569 ◽  
Author(s):  
Marina Bicalho Silveira ◽  
Marcella Araugio Soares ◽  
Eduardo Sarmento Valente ◽  
Samira Soares Waquil ◽  
Andréa Vidal Ferreira ◽  
...  
Keyword(s):  
Quality Control ◽  
Sodium Fluoride ◽  
Radiochemical Purity ◽  
Nuclear Technology ◽  
Physical Chemical ◽  
Positron Emission ◽  
Oncological Diseases ◽  
Pet Scans ◽  
Quality Imaging ◽  
The U.S

18F-Sodium fluoride (Na18F) is a radiopharmaceutical used for diagnosis in nuclear medicine by positron emission tomography (PET) imaging. Bone scintigraphy is normally performed using 99mTc-MDP. However, 18F PET scans promise high quality imaging with increased resolution and improved sensitivity and specificity. In order to make available a tool for more specific studies of tumors and non-oncological diseases of bone tissue, the UPPR/CDTN team undertook the production and quality control of Na18F injectable solution with the physical-chemical, microbiological and biological characteristics recommended in the U.S. Pharmacopeia. Na18F radiochemical purity was 96.7 ± 1.3 %, with Rf= 0.026 ± 0.006. The product presented a pH of 5.3 ± 0.6, half life of 109.0 ± 0.8 minutes, endotoxin limit < 5.0 EU.mL-1 and no microbial contaminants. The biodistribution of Na18F was similar to that described in the literature, with a clearance of 0.19 mL.min-1 and distribution volume of 18.76 mL. The highest bone concentration (5.0 ± 0.5 %ID.g-1) was observed 20 minutes after injection. Na18F produced at the UPPR presented all the quality assurance requirements of the U.S. Pharmacopeia and can be safely used for clinical bone imaging.

scholarly journals Phaseless Gauss-Newton Inversion for Microwave Imaging

2020 ◽  
Author(s):  
Chaitanya Narendra ◽  
Puyan Mojabi
Keyword(s):  
Field Data ◽  
Prior Information ◽  
Structural Information ◽  
Microwave Imaging ◽  
The Other ◽  
Total Field ◽  
Field Phase ◽  
Full Data ◽  
L2 Norm ◽  
Phase Data

<p>A phaseless Gauss-Newton inversion (GNI) algorithm is developed for microwave imaging applications. In contrast to full-data microwave imaging inversion that uses complex (magnitude and phase) scattered field data, the proposed phaseless GNI algorithm inverts phaseless (magnitude-only) total field data. This phaseless Gauss-Newton inversion (PGNI) algorithm is augmented with three different forms of regularization, originally developed for complex GNI. First, we use the standard weighted L2 norm total variation multiplicative regularizer which is appropriate when there is no prior information about the object being imaged. We then use two other forms of regularization operators to incorporate prior information about the object being imaged into the PGNI algorithm. The first one, herein referred to as SL-PGNI, incorporates prior information about the expected relative complex permittivity values of the object of interest. The other, referred to as SP-PGNI, incorporates spatial priors (structural information) about the objects being imaged. The use of prior information aims to compensate for the lack of total field phase data. The PGNI, SL-PGNI, and SP-PGNI inversion algorithms are then tested against synthetic and experimental phaseless total field data.</p>

scholarly journals Determination of receptor occupancy in the presence of mass dose: [11C]GSK189254 PET imaging of histamine H3 receptor occupancy by PF-03654746

2016 ◽  
Vol 37 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Jean-Dominique Gallezot ◽  
Beata Planeta ◽  
Nabeel Nabulsi ◽  
Donna Palumbo ◽  
Xiaoxi Li ◽  
...  
Keyword(s):  
Binding Sites ◽  
Human Subjects ◽  
Receptor Occupancy ◽  
Healthy Human ◽  
Positron Emission ◽  
Relationship Of ◽  
The Relationship ◽  
Pet Scans

Measurements of drug occupancies using positron emission tomography (PET) can be biased if the radioligand concentration exceeds “tracer” levels. Negative bias would also arise in successive PET scans if clearance of the radioligand is slow, resulting in a carryover effect. We developed a method to (1) estimate the in vivo dissociation constant Kd of a radioligand from PET studies displaying a non-tracer carryover (NTCO) effect and (2) correct the NTCO bias in occupancy studies taking into account the plasma concentration of the radioligand and its in vivo Kd. This method was applied in a study of healthy human subjects with the histamine H3 receptor radioligand [11C]GSK189254 to measure the PK-occupancy relationship of the H3 antagonist PF-03654746. From three test/retest studies, [11C]GSK189254 Kd was estimated to be 9.5 ± 5.9 pM. Oral administration of 0.1 to 4 mg of PF-03654746 resulted in occupancy estimates of 71%–97% and 30%–93% at 3 and 24 h post-drug, respectively. NTCO correction adjusted the occupancy estimates by 0%–15%. Analysis of the relationship between corrected occupancies and PF-03654746 plasma levels indicated that PF-03654746 can fully occupy H3 binding sites ( ROmax = 100%), and its IC50 was estimated to be 0.144 ± 0.010 ng/mL. The uncorrected IC50 was 26% higher.

scholarly journals Approaching Complete Inhibition of P-Glycoprotein at the Human Blood–Brain Barrier: An (R)-[11C]Verapamil PET Study

2015 ◽  
Vol 35 (5) ◽  
pp. 743-746 ◽  
Author(s):  
Martin Bauer ◽  
Rudolf Karch ◽  
Markus Zeitlinger ◽  
Cécile Philippe ◽  
Kerstin Römermann ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Brain Barrier ◽  
Distribution Volume ◽  
Emission Tomography ◽  
Brain Barrier ◽  
Whole Brain ◽  
P Glycoprotein ◽  
Blood Brain ◽  
Positron Emission ◽  
Pet Scans

As P-glycoprotein (Pgp) inhibition at the blood–brain barrier (BBB) after administration of a single dose of tariquidar is transient, we performed positron emission tomography (PET) scans with the Pgp substrate ( R)-[11C]verapamil in five healthy volunteers during continuous intravenous tariquidar infusion. Total distribution volume ( VT) of ( R)-[11C]verapamil in whole-brain gray matter increased by 273 ± 78% relative to baseline scans without tariquidar, which was higher than previously reported VT increases. During tariquidar infusion whole-brain VT was comparable to VT in the pituitary gland, a region not protected by the BBB, which suggested that we were approaching complete Pgp inhibition at the human BBB.

Effect of grain or silage supplementation on meat quality attributes of cryptorchid lambs grazing lucerne or annual grass-clover pastures

1995 ◽  
Vol 35 (4) ◽  
pp. 461 ◽  
Author(s):  
DL Hopkins ◽  
PJ Holst ◽  
DG Hall
Keyword(s):  
Meat Quality ◽  
Shear Force ◽  
The Other ◽  
Carcass Weight ◽  
Annual Grass ◽  
Eye Muscle ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Ad Libitum

Objective and subjective tests for quality were performed on the meat from 40 cryptorchid second-cross lambs fed lucerne only (L; n = 8), lucerne plus an oat grain supplement ad libitum (LO; n = lo), lucerne plus wilted lucerne silage ad libitum (LS; n = 11), or an oat-lupin grain (3:1) supplement at 90% of ad libitum while grazing dry summer annual pasture (OL; n = 11). All carcasses complied with the Elite lamb specification of weight >22 kg and GR measurement 6-15 mm. There was no significant difference between groups for hot carcass weight, the mean (� s.e) values being 25.1 0.43, 25.2 � 0.36,25.2 � 0.38, and 25.3 � 0.36 kg for L, LS, LO, and OL groups, respectively. When the GR and fat depth over the eye muscle at the 12th rib were adjusted to a common carcass weight of 25.2 kg there was no significant difference between groups. There was no significant difference between groups for pH, or the colour values a*, b*, and L* of the M. longissimus thoracis et lumborum (a* is relative redness, b* relative yellowness, and L* relative lightness). The shear force values for the loin muscle were significantly (P<0.05) greater for lambs from group OL than for those from group LO. Cooking loss for the loin muscle was significantly (P<0.05) greater for OL lambs than all other groups. A comparison of the mean values for aroma and flavour showed the lambs from group OL produced meat that was considered significantly (P<0.05) less desirable for these characteristics, with other groups being similar. Meat from OL-fed lambs was considered oilier and less meaty than meat from lambs fed the other diets. There was a significant (P<0.05) difference in absolute scores between panellists, but their ranking was not affected and there was no panellist x sample interaction. Because many producers use grain supplements such as oats and lupins for finishing lambs on dry forages, further study is recommended that focuses on the interaction between supplement and the base forage.

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