Relationship between relative cerebral blood flow, relative cerebral blood volume, and relative cerebral metabolic rate of oxygen in the preterm neonatal brain

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.

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Effects of increased intracranial pressure on cerebral blood volume, blood flow, and oxygen utilization in monkeys

Journal of Neurosurgery ◽

10.3171/jns.1975.43.4.0385 ◽

1975 ◽

Vol 43 (4) ◽

pp. 385-398 ◽

Cited By ~ 138

Author(s):

Robert L. Grubb ◽

Marcus E. Raichle ◽

Michael E. Phelps ◽

Robert A. Ratcheson

Keyword(s):

Blood Flow ◽

Intracranial Pressure ◽

Metabolic Rate ◽

Intracranial Hypertension ◽

Cerebral Perfusion Pressure ◽

Blood Volume ◽

Cerebral Perfusion ◽

Cerebral Blood Volume ◽

Perfusion Pressure ◽

Cerebral Metabolic Rate

✓ The relationship of cerebral blood volume (CBV) to cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and the cerebral metabolic rate for oxygen (CMRO2) was examined in rhesus monkeys. In vivo tracer methods employing radioactive oxygen-15 were used to measure CBV, CBF, and CMRO2. Cerebral perfusion pressure was decreased by raising the intracranial pressure (ICP) by infusion of artificial cerebrospinal fluid (CSF) into the cisterna magna. The production of progressive intracranial hypertension to an ICP of 70 torr (CPP of 40 torr) caused a rise in CBV accompanied by a steady CBF. With a further increase in ICP to 94 torr, CBV remained elevated without change while CBF declined significantly. Cerebral metabolic rate for oxygen did not change significantly during intracranial hypertension. For comparison, CPP was lowered by reducing mean arterial blood pressure in a second group of monkeys. Only CBF was measured in this group. In this second group of animals, the lower limit of CBF autoregulation was reached at a higher CPP (CPP ∼ 80 torr) than when an increase in ICP was employed (CPP ∼ 30 torr).

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Brain hemorrhage after endovascular reperfusion therapy of ischemic stroke: a threshold-finding whole-brain perfusion CT study

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x15621704 ◽

2016 ◽

Vol 37 (1) ◽

pp. 153-165 ◽

Cited By ~ 12

Author(s):

Arturo Renú ◽

Carlos Laredo ◽

Raúl Tudela ◽

Xabier Urra ◽

Antonio Lopez-Rueda ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Blood Volume ◽

Cerebral Blood Volume ◽

Reperfusion Therapy ◽

Perfusion Ct ◽

Regression Analyses ◽

Relative Cerebral Blood Volume

Endovascular reperfusion therapy is increasingly used for acute ischemic stroke treatment. The occurrence of parenchymal hemorrhage is clinically relevant and increases with reperfusion therapies. Herein we aimed to examine the optimal perfusion CT-derived parameters and the impact of the duration of brain ischemia for the prediction of parenchymal hemorrhage after endovascular therapy. A cohort of 146 consecutive patients with anterior circulation occlusions and treated with endovascular reperfusion therapy was analyzed. Recanalization was assessed at the end of reperfusion treatment, and the rate of parenchymal hemorrhage at follow-up neuroimaging. In regression analyses, cerebral blood volume and cerebral blood flow performed better than Delay Time maps for the prediction of parenchymal hemorrhage. The most informative thresholds (receiver operating curves) for relative cerebral blood volume and relative cerebral blood flow were values lower than 2.5% of normal brain. In binary regression analyses, the volume of regions with reduced relative cerebral blood volume and/or relative cerebral blood flow was significantly associated with an increased risk of parenchymal hemorrhage, as well as delayed vessel recanalization. These results highlight the relevance of the severity and duration of ischemia as drivers of blood-brain barrier disruption in acute ischemic stroke and support the role of perfusion CT for the prediction of parenchymal hemorrhage.

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S -Ketamine Anesthesia Increases Cerebral Blood Flow in Excess of the Metabolic Needs in Humans

Anesthesiology ◽

10.1097/00000542-200508000-00008 ◽

2005 ◽

Vol 103 (2) ◽

pp. 258-268 ◽

Cited By ~ 92

Author(s):

Jaakko W. Långsjö ◽

Anu Maksimow ◽

Elina Salmi ◽

Kaike Kaisti ◽

Sargo Aalto ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Metabolic Rate ◽

Blood Volume ◽

Cerebral Blood Volume ◽

Brain Structures ◽

Anterior Cingulate ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Whole Brain

Background Animal studies have demonstrated neuroprotective properties of S-ketamine, but its effects on cerebral blood flow (CBF), metabolic rate of oxygen (CMRO2), and glucose metabolic rate (GMR) have not been comprehensively studied in humans. Methods Positron emission tomography was used to quantify CBF and CMRO2 in eight healthy male volunteers awake and during S-ketamine infusion targeted to subanesthetic (150 ng/ml) and anesthetic (1,500-2,000 ng/ml) concentrations. In addition, subjects' GMRs were assessed awake and during anesthesia. Whole brain estimates for cerebral blood volume were obtained using kinetic modeling. Results The mean +/- SD serum S-ketamine concentration was 159 +/- 21 ng/ml at the subanesthetic and 1,959 +/- 442 ng/ml at the anesthetic levels. The total S-ketamine dose was 10.4 mg/kg. S-ketamine increased heart rate (maximally by 43.5%) and mean blood pressure (maximally by 27.0%) in a concentration-dependent manner (P = 0.001 for both). Subanesthetic S-ketamine increased whole brain CBF by 13.7% (P = 0.035). The greatest regional CBF increase was detected in the anterior cingulate (31.6%; P = 0.010). No changes were detected in CMRO2. Anesthetic S-ketamine increased whole brain CBF by 36.4% (P = 0.006) but had no effect on whole brain CMRO2 or GMR. Regionally, CBF was increased in nearly all brain structures studied (greatest increase in the insula 86.5%; P < 0.001), whereas CMRO2 increased only in the frontal cortex (by 15.7%; P = 0.007) and GMR increased only in the thalamus (by 11.7%; P = 0.010). Cerebral blood volume was increased by 51.9% (P = 0.011) during anesthesia. Conclusions S-ketamine-induced CBF increases exceeded the minor changes in CMRO2 and GMR during anesthesia.

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Cerebral Blood Flow and Cerebral Metabolic Rate of Oxygen Requirements for Cerebral Function and Viability in Humans

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1985.89 ◽

1985 ◽

Vol 5 (4) ◽

pp. 600-608 ◽

Cited By ~ 301

Author(s):

William J. Powers ◽

Robert L. Grubb ◽

Danielle Darriet ◽

Marcus E. Raichle

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Metabolic Rate ◽

Cerebral Blood Volume ◽

Oxygen Extraction Fraction ◽

Neurological Deficits ◽

Regional Cerebral Blood ◽

Cerebral Tissue ◽

Cerebral Metabolic Rate ◽

Regional Cerebral Blood Volume

This study was undertaken to determine the minimum CBF and CMRO2 required by the human brain to maintain normal function and viability for more than a few hours. Positron emission tomography (PET) was used to perform regional measurements in 50 subjects with varying degrees of cerebral ischemia but no evidence of infarction. There were 24 normal subjects, 24 subjects with arteriographic evidence of vascular disease of the carotid system, and two subjects with reversible ischemic neurological deficits due to cerebral vasospasm. Minimum values found in the 48 subjects with normal neurological function were 19 ml/100 g-min for regional cerebral blood flow (rCBF) and 1.3 ml/100 g-min for regional cerebral metabolic rate of oxygen (rCMRO2). Minimum values for all 50 subjects with viable cerebral tissue were 15 ml/100 g-min for rCBF and 1.3 ml/100 g-min for rCMRO2. Comparison of these measurements with values from 20 areas of established cerebral infarction in 10 subjects demonstrated that 80% (16/20) of infarcted regions had rCMRO2 values below the lower normal limit of 1.3 ml/100g-min. Measurements of rCBF, regional cerebral blood volume, and oxygen extraction fraction were less useful for distinguishing viable from infarcted tissue. These data indicate that quantitative regional measurements of rCMRO2 with PET accurately distinguish viable from nonviable cerebral tissue and may be useful in the prospective identification of patients with reversible ischemia.

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Striatal and Cortical BOLD, Blood Flow, Blood Volume, Oxygen Consumption, and Glucose Consumption Changes in Noxious Forepaw Electrical Stimulation

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2010.173 ◽

2010 ◽

Vol 31 (3) ◽

pp. 832-841 ◽

Cited By ~ 38

Author(s):

Yen-Yu I Shih ◽

Hsiao-Ying Wey ◽

Bryan H De La Garza ◽

Timothy Q Duong

Keyword(s):

Blood Flow ◽

Oxygen Consumption ◽

Metabolic Rate ◽

Blood Volume ◽

Functional Imaging ◽

Cerebral Blood Volume ◽

Glucose Consumption ◽

Blood Oxygenation ◽

Cerebral Metabolic Rate ◽

Positron Emission

Recent reports showed noxious forepaw stimulation in rats evoked an unexpected sustained decrease in cerebral blood volume (CBV) in the bilateral striatum, whereas increases in spike activity and Fos-immunoreactive cells were observed. This study aimed to further evaluate the hemodynamic and metabolic needs in this model and the sources of negative functional magnetic resonance imaging (fMRI) signals by measuring blood oxygenation-level-dependent (BOLD), cerebral-blood-flow (CBF), CBV, and oxygen-consumption (i.e., cerebral metabolic rate of oxygen (CMRO2)) changes using an 11.7-T MRI scanner, and glucose-consumption (i.e., cerebral metabolic rate of glucose (CMRglc)) changes using micro-positron emission tomography. In the contralateral somatosensory cortex, BOLD, CBF, CBV, CMRO2 ( n=7, P<0.05), and CMRglc ( n=5, P<0.05) increased. In contrast, in the bilateral striatum, BOLD, CBF, and CBV decreased ( P<0.05), CMRO2 decreased slightly, although not significantly from baseline, and CMRglc was not statistically significant from baseline ( P>0.05). These multimodal functional imaging findings corroborate the unexpected negative hemodynamic changes in the striatum during noxious forepaw stimulation, and support the hypothesis that striatal hemodynamic response is dominated by neurotransmitter-mediated vasoconstriction, overriding the stimulus-evoked fMRI signal increases commonly accompany elevated neuronal activity. Multimodal functional imaging approach offers a means to probe the unique attributes of the striatum, providing novel insights into the neurovascular coupling in the striatum. These findings may have strong implications in fMRI studies of pain.

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