Cerebral [<sup>15</sup>O]Water Clearance in Humans Determined by PET: I. Theory and Normal Values

Ohta, Shinsuke; Meyer, Ernst; Fujita, Hitoshi; Reutens, David C.; Evans, Alan C.; Gjedde, Albert

doi:10.1097/00004647-199609000-00002

Cited by 141 publications

(163 citation statements)

References 26 publications

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“…This significant reduction of parameters in the region of cerebral infarction was similar to a previous report (Temma et al, 2006). A single-compartment analysis used in the steady-state method may overestimate cerebral water clearance and tissue counts (Ohta et al, 1992(Ohta et al, , 1996; however, this method was established in human PET studies and many studies with CVD patients were reported (Yamauchi et al, 1996(Yamauchi et al, , 1998(Yamauchi et al, , 1999Okazawa et al, 2001;Ouchi et al, 2001). Although slightly different values were observed between the steady-state method and the bolus administration method in a previous study with CVD, the values were not significantly different (Okazawa et al, 2001).…”

Section: Discussionsupporting

confidence: 88%

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method

Kobayashi

Mori

Kiyono

et al. 2011

J Cereb Blood Flow Metab

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To develop a less-stressful and simple method for measurement of the cerebral metabolic rate of oxygen (CMRO 2 ) in small animals, the steady-state method was applied to injectable 15 O 2 -PET ( 15 O 2 -positron emission tomography) using hemoglobin-containing vesicles ( 15 O 2 -HbV). Ten normal rats and 10 with middle cerebral arterial occlusion (MCAO) were studied using a small animal PET scanner. A series of 15 O-PET scans with C 15 O-labeled HbV, H 2 15 O, and 15 O 2 -HbV were performed with 10 to 15 minutes intervals to measure cerebral blood volume (CBV), cerebral blood flow (CBF), and CMRO 2 . Positron emission tomography scans were started with a tracer injection using a multiprogramming syringe pump, which provides a slowly increasing injection volume to achieve steady-state radioactivity for H 2 15 O and 15 O 2 -HbV scans. The radioactivity concentration of 15 O rapidly achieved equilibrium in the blood and whole brain at about 2 minutes after H 2 15 O and 15 O 2 -HbV administration, which was stable during the scans. The whole brain mean values of CBF, CBV, and CMRO 2 were 54.3 ± 2.0 mL per 100 g per minute, 4.9 ± 0.4 mL/100 g, and 2.8 ± 0.2 lmoL per g per minute (6.2±0.4 mL per 100 g per minute) in the normal rats, respectively. In the MCAO model rats, all hemodynamic parameters of the infarction area on the occlusion side significantly decreased. The steady-state method with 15 O-labeled HbV is simple and useful to analyze hemodynamic changes in studies with model animals.

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Section: Discussionsupporting

confidence: 88%

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method

Kobayashi

Mori

Kiyono

et al. 2011

J Cereb Blood Flow Metab

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“…This effect, called ''signal enhancement by extravascular protons'' (SEEP) [Stroman et al, 2002c[Stroman et al, , 2003b[Stroman et al, , 2005b, is thought to arise from a local change in fluid balance, which in turn may result from changes in perfusion pressure, production of extracellular fluid, neurons and glial cells swelling, and maintenance of ion and neurotransmitter concentrations at sites of neuronal activity [Fujita et al, 1997;Ohta et al, 1996;Stroman and Andrew, 2007;Stroman et al, 2002cStroman et al, , 2003bStroman et al, , 2005b. Previous studies showed that both the BOLD and the SEEP effects give a contribution to the signal change observed during spinal fMRI activity, with different relative proportions depending on field strength and TE value used [Stroman, 2005;Stroman et al, 2002c].…”

Section: Discussionmentioning

confidence: 99%

Tactile‐associated fMRI recruitment of the cervical cord in healthy subjects

Valsasina

Caputo

Rocca

et al. 2007

Human Brain Mapping

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Using spinal cord functional magnetic resonance imaging (fMRI), 12 right-handed healthy subjects were scanned during a tactile stimulation of the palm of the right hand. The task-related mean signal change was computed for all activated voxels within the cervical cord, and separately, in the four cord quadrants (right and left anterior, right and left posterior) from C5 to C8. The frequency of fMRI activity at each cord level was obtained by assigning a score of 25% at each active quadrant and by averaging the percentage of active quadrants at each level of all subjects. The difference in the occurrence of fMRI activity (a) in right versus left, and anterior versus posterior cord, and (b) among the different cord levels, was evaluated using a random effect logistic regression model, with the frequency of fMRI activity as the dependent variable and the subject as the grouping factor. The taskrelated mean signal change of all activated voxels of the cord was 3.2% (SD 5 0.8%). During the tactile stimulation, subjects showed a higher occurrence of fMRI cord activity in the right than in the left cervical cord (odds ratio 5 2.25, 95% confidence interval 5 1.31-3.87, P 5 0.003). A significant heterogeneity in frequency of fMRI activity between cord levels was also observed (P < 0.001), with the highest frequencies of fMRI activity detected at C6 and C7. Spinal cord fMRI enables to obtain reliable physiological information on the activity of human spinal circuits associated to tactile stimulation. This holds significant promise for a better planning and conduct of studies of people with diseased spinal cords.

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“…According to this model, the radioactivity concentration in a brain region is expressed as follows (Iida et al, 1991;Ito et al, 2001;Ohta et al, 1996):…”

Section: Kinetic Analysismentioning

confidence: 99%

Changes in the Arterial Fraction of Human Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

Ito

Ibaraki

Kanno

et al. 2005

J Cereb Blood Flow Metab

137

107

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Hypercapnia induces cerebral vasodilation and increases cerebral blood volume (CBV), and hypocapnia induces cerebral vasoconstriction and decreases CBV. Cerebral blood volume measured by positron emission tomography (PET) is the sum of three components, that is, arterial, capillary, and venous blood volumes. Changes in arterial blood volume (V a ) and CBV during hypercapnia and hypocapnia were investigated in humans using PET with H 2 15 O and 11 CO. Arterial blood volume was determined from H 2 15 O PET data by means of a two-compartment model that takes V a into account. Baseline CBV and values during hypercapnia and hypocapnia in the cerebral cortex were 0.03470.003, 0.03870.003, and 0.03170.003 mL/mL (mean7s.d.), respectively. Baseline V a and values during hypercapnia and hypocapnia were 0.01570.003, 0.02570.011, and 0.0077 0.003 mL/mL, respectively. Cerebral blood volume changed significantly owing to changes in PaCO 2 , and V a changed significantly in the direction of CBV changes. However, no significant change was observed in venous plus capillary blood volume ( ¼ CBVÀV a ). This indicates that changes in CBV during hypercapnia and hypocapnia are caused by changes in arterial blood volume without changes in venous and capillary blood volume.

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Cerebral [¹⁵O]Water Clearance in Humans Determined by PET: I. Theory and Normal Values

Cited by 141 publications

References 26 publications

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method

Tactile‐associated fMRI recruitment of the cervical cord in healthy subjects

Changes in the Arterial Fraction of Human Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

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Cerebral [15O]Water Clearance in Humans Determined by PET: I. Theory and Normal Values

Cited by 141 publications

References 26 publications

Cerebral Oxygen Metabolism of Rats using Injectable 15O-Oxygen with a Steady-State Method

Cerebral Oxygen Metabolism of Rats using Injectable 15O-Oxygen with a Steady-State Method

Tactile‐associated fMRI recruitment of the cervical cord in healthy subjects

Changes in the Arterial Fraction of Human Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

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Product

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Cerebral [¹⁵O]Water Clearance in Humans Determined by PET: I. Theory and Normal Values

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method

Cerebral Oxygen Metabolism of Rats using Injectable ¹⁵O-Oxygen with a Steady-State Method