scholarly journals Blood Flow Distribution in Cerebral Arteries

2015 ◽  
Vol 35 (4) ◽  
pp. 648-654 ◽  
Author(s):  
Laleh Zarrinkoob ◽  
Khalid Ambarki ◽  
Anders Wåhlin ◽  
Richard Birgander ◽  
Anders Eklund ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Artery ◽  
Flow Rate ◽  
Cerebral Perfusion ◽  
Brain Volume ◽  
Cerebral Arteries ◽  
Blood Flow Rate ◽  
Collateral Flow ◽  
Vascular Tree

High-resolution phase—contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra- and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717±123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21%; distal MCA, 6%; anterior cerebral artery (ACA), 12%, distal ACA, 4%; ophthalmic artery, 2%; posterior cerebral artery (PCA), 8%; and 20% to basilar artery. Deviating distributions were observed in subjects with ‘fetal’ PCA. Blood flow rate in cerebral arteries decreased with increasing age ( P<0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61±8; men: 55±6 mL/min/100 mL, P<0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system.

scholarly journals Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

2016 ◽  
Vol 3 (8) ◽  
pp. 160305 ◽  
Author(s):  
Roger S. Seymour ◽  
Vanya Bosiocic ◽  
Edward P. Snelling
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Metabolic Rate ◽  
Flow Rate ◽  
Brain Volume ◽  
Brain Size ◽  
Blood Flow Rate ◽  
Fold Increase ◽  
Cerebral Tissue ◽  
Cerebral Metabolic Rate

The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens , increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.

scholarly journals Total Cerebral Blood Flow and Total Brain Perfusion in the General Population: The Rotterdam Scan Study

2007 ◽  
Vol 28 (2) ◽  
pp. 412-419 ◽  
Author(s):  
Meike W Vernooij ◽  
Aad van der Lugt ◽  
Mohammad Arfan Ikram ◽  
Piotr A Wielopolski ◽  
Henri A Vrooman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
General Population ◽  
Cerebral Perfusion ◽  
Brain Volume ◽  
Measurement Techniques ◽  
White Matter Lesions ◽  
Brain Perfusion ◽  
Linear Regression Models ◽  
Total Brain

Reduced cerebral perfusion may contribute to the development of cerebrovascular and neurodegenerative diseases. Little is known on cerebral perfusion in the general population, as most measurement techniques are too invasive for application in large groups of healthy individuals. Total cerebral blood flow (tCBF) can be noninvasively measured by magnetic resonance imaging (MRI) but is highly correlated with brain volume. We calculated total brain perfusion by dividing tCBF by brain volume, and we investigated determinants of total brain perfusion in comparison with tCBF. Secondly, we studied whether persons with a low tCBF or low total brain perfusion have a larger volume of white matter lesions (WML). This study is based on 892 persons aged 60 to 91 years from the Rotterdam Study, a population-based cohort study. We performed two-dimensional (2D) phase-contrast MRI for tCBF measurement. Brain volume and WML volume were quantitatively assessed. Cardiovascular determinants were assessed by interview and physical examination. We assessed associations between cardiovascular determinants and flow measures with linear regression models, adjusted for age and sex. Associations between tCBF or total brain perfusion and WML volume were assessed using general linear models. We found that determinants of tCBF and total brain perfusion differed largely due to the large influence of brain volume on tCBF values. Persons with low total brain perfusion had a significantly larger WML volume compared with those with high total brain perfusion. Prospective studies are required to unravel whether hypoperfusion contributes to WML formation or that tissue damage, manifested by WML, leads to brain hypoperfusion.

scholarly journals Catechin prevents severe dyslipidemia-associated changes in wall biomechanics of cerebral arteries in LDLr−/−:hApoB+/+ mice and improves cerebral blood flow

2012 ◽  
Vol 302 (6) ◽  
pp. H1330-H1339 ◽  
Author(s):  
Virginie Bolduc ◽  
Edward Baraghis ◽  
Natacha Duquette ◽  
Nathalie Thorin-Trescases ◽  
Jean Lambert ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Endothelial Dysfunction ◽  
Cerebral Artery ◽  
Cerebral Arteries ◽  
Strain Curve ◽  
Cerebral Hypoperfusion ◽  
Wall Structure ◽  
Artery Wall

Endothelial dysfunction and oxidative stress contribute to the atherosclerotic process that includes stiffening of large peripheral arteries. In contrast, our laboratory previously reported a paradoxical increase in cerebrovascular compliance in LDLr−/−:hApoB+/+ atherosclerotic (ATX) mice ( 7 ). We hypothesized that prevention of cerebral artery endothelial dysfunction with a chronic dietary antioxidant intake would normalize the changes in cerebral artery wall structure and biomechanics and prevent the decline in basal cerebral blood flow associated with atherosclerosis. Three-month-old ATX mice were treated, or not, for 3 mo with the polyphenol (+)-catechin (CAT; 30 mg·kg−1·day−1) and compared with wild-type controls. In isolated, pressurized cerebral arteries from ATX mice, CAT prevented endothelial dysfunction (deterioration of endothelium-dependent, flow-mediated dilations; P < 0.05), the inward hypertrophic structural remodeling (increase in the wall-to-lumen ratio; P < 0.05), and the rise in cerebrovascular compliance (rightward shift of the stress-strain curve measured in passive conditions, reflecting mechanical properties of the arterial wall; P < 0.05). Doppler optical coherence tomography imaging in vivo confirmed these findings, showing that cerebral compliance was higher in ATX mice and normalized by CAT ( P < 0.05). CAT also prevented basal cerebral hypoperfusion in ATX mice ( P < 0.05). Active remodeling of the cerebrovascular wall in ATX mice was further suggested by the increase ( P < 0.05) in pro-metalloproteinase-9 activity, which was normalized by CAT. We conclude that, by preserving the endothelial function, a chronic treatment with CAT prevents the deleterious effect of severe dyslipidemia on cerebral artery wall structure and biomechanical properties, contributing to preserving resting cerebral blood flow.

Selected Contribution: Effects of aging on cerebrovascular tone and [Ca2+]i

2003 ◽  
Vol 95 (4) ◽  
pp. 1746-1754 ◽  
Author(s):  
Greg G. Geary ◽  
John N. Buchholz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Artery ◽  
Cerebral Arteries ◽  
No Synthase ◽  
The Other ◽  
Intraluminal Pressure ◽  
Age Dependent ◽  
Old Rats ◽  
Cerebral Blood Flow Autoregulation

The lower limits of cerebral blood flow autoregulation shift toward high pressures in aged compared with young rats. Intraluminal pressure stimulates contractile mechanisms in cerebral arteries that might, in part, cause an age-dependent shift in autoregulation. The present project tested two hypotheses. First, cerebral artery tone is greater in isolated arteries from aged compared with mature adult rats. Second, aging decreases the modulatory effect of endothelium-derived nitric oxide (NO) and increases vascular smooth muscle Ca2+ sensitivity. Isolated segments of middle cerebral arteries from male 6-, 12-, 20-, and 24-mo-old Fischer 344 rats were cannulated and loaded with fura-2. Diameter and Ca2+ responses to increasing pressure were measured in HEPES, during NO synthase inhibition [ NG-nitro-l-arginine methyl ester (l-NAME)], and after removal of the endothelium. Cerebral artery tone (with endothelium) increased with age. Only at the lowest pressure (20 and 40 mmHg) was intracellular Ca2+ concentration ([Ca2+]i) greater in arteries from 24-mo-old rats compared with the other age groups. l-NAME-sensitive constriction increased significantly in arteries from 6- to 20-mo-old rats but declined significantly thereafter in arteries from 24-mo-old rats. [Ca2+]i was less in arteries from 24-mo-old rats compared with the other groups after treatment with l-NAME. Another endothelial-derived factor, insensitive to l-NAME, also decreased significantly with age. For example, at 60 mmHg, the l-NAME-insensitive constriction decreased from 47 ± 10, 42 ± 5, 21 ± 2, and 3 ± 1 μm in 6-, 12-, 20-, and 24-mo-old rats, respectively. Our data suggest that aging alters cerebral artery tone and [Ca2+]i responses through endothelial-derived NO synthase-sensitive and -insensitive mechanisms. The combined effect of greater cerebral artery tone with less endothelium-dependent modulation may in part contribute to the age-dependent shift in cerebral blood flow autoregulation.

Changes in local cerebral blood flow following profound systemic hypotension

1976 ◽  
Vol 44 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Francis W. Gamache ◽  
Ronald E. Myers ◽  
Esteban Monell
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Rate ◽  
Rank Order ◽  
Blood Flow Rate ◽  
Rapid Onset ◽  
Border Zone ◽  
Local Cerebral Blood Flow ◽  
Content Type ◽  
The Brain

✓ The authors studied local cerebral blood flow in monkeys rendered hypotensive by infusion of a ganglionic blocking agent. Application of the 14C-antipyrine method demonstrated that the blood flow: 1) normally varies reproducibly from one structure to another within the brain; 2) appears at its lowest level in all structures during the early minutes of a rapid-onset hypotension; 3) maintains the same general rank order of blood flow rate during hypotension as was present during normotension; and 4) returns to supranormal levels immediately following the rapid restoration of blood pressure. The values for local cerebral blood flow remain close-to-normal in some animals and diminish significantly in others during late recovery from hypotension. The close-to-normal values accompany uncomplicated recoveries while the diminished values appear in those animals which became neurologically depressed. Areas of the brain considered predisposed to hypotensive injury did not exhibit depressions in blood flow rate during hypotension more markedly than did other brain areas. The present results are interpreted as strong evidence against the “border zone” hypothesis.

scholarly journals Inter- and Intra-Rater Reliability of Individual Cerebral Blood Flow Measured by Quantitative Vessel-Flow Phase-Contrast MRI

2020 ◽  
Vol 9 (10) ◽  
pp. 3099
Author(s):  
Kwang-Hwa Chang ◽  
Yuan-Hao Lee ◽  
Chia-Yuen Chen ◽  
Ming-Fang Lin ◽  
Ying Chin Lin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Correlation Coefficient ◽  
Cerebral Artery ◽  
Phase Contrast ◽  
Cerebral Arteries ◽  
Intraclass Correlation ◽  
Vessel Flow

Vessel flow quantification by two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) using a three-dimensional (3D) magnetic resonance angiography (MRA) model to measure cerebral blood flow has unclear analytical reliability. The present study aimed to determine the inter- and intra-rater reliability of quantitative vessel-flow PC-MRI and potential factors influencing its consistency. We prospectively recruited 30 Asian participants (aged 20–90 years; 16 women; 22 healthy and 8 stroke patients) for performing 1.5-T MR equipped with a head coil. Each participant was first scanned for time-of-flight magnetic resonance angiography (TOF-MRA) images for localization of intracranial arteries. The 2D PC-MRI for each cerebral artery (total 13 arteries in fixed order) was performed twice by two well-trained operators in optimal position. Using the same 3D MRA as a map and facilitated with the non-invasive optimal vessel analysis (NOVA) system, each scan was taken on a plane perpendicular to the target artery. Two consecutive full 13-artery scans were performed at least 15 min apart after participants were removed from the scanner table and then repositioned. A total of four PC flow images obtained from each target artery were transmitted to a workstation facilitated with the NOVA system. Flow data were calculated semi-automatically by the NOVA system after a few simple steps. Two-way mixed-effect models and standard errors of measurements were used. In 13 cerebral arteries, repeatability, using the intra-rater estimate expressed as the average-measures intraclass correlation coefficient, ranged from 0.641 to 0.954, and reproducibility, using the inter-rater estimate, ranged from 0.672 to 0.977. Except in the middle cerebral artery and the distal segment of the anterior cerebral artery, repeatability and reproducibility were excellent (intraclass correlation coefficient exceeded 0.8). The use of quantitative vessel-flow PC-MRI is a precise means to measure blood flow in most target cerebral arteries. This was evidenced by inter-rater and intra-rater correlations that were good/excellent, indicating good reproducibility and repeatability.

Cerebral blood flow of children with vasovagal syncope

2014 ◽  
Vol 25 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Barsan Tugba ◽  
Kilic Zubeyir ◽  
Uzuner Nevzat ◽  
Yildirim Ali ◽  
Ucar Birsen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Flow Rate ◽  
Vasovagal Syncope ◽  
Blood Flow Rate ◽  
Tilt Test ◽  
Control Group ◽  
Group 2 ◽  
Group 1

AbstractIntroduction: We aimed to evaluate changes in the cerebral blood supply in children during vasovagal syncope and to clarify the diagnostic value of transcranial Doppler for vasovagal syncope. Materials and methods: Patients were divided into three groups. Group 1 consisted of 31 patients who were symptomatic and whose head-up tilt test was positive. Group 2 comprised 21 patients who were symptomatic but whose tilt test was negative. Group 3 included 22 healthy children. For the diagnosis of vasovagal syncope, the tilt test was applied. For the subjects of the patient and control groups, the tilt test was repeated. The flow rates of bilateral middle cerebral arteries were continuously and simultaneously recorded with temporal window transcranial Doppler. Results: There were no statistically significant differences between the three groups with respect to age and gender distribution (p>0.05). When the bed was at an upright position, the maximum blood flow rate of the right middle cerebral artery was lower in Group 1 than in Group 2, although the decrease was more significant in comparison to the healthy control group (p<0.05). The minimum blood flow rate of the right middle cerebral artery was lower in Group 1 than the Group 2, although the decrease was more significant in comparison with the healthy control group (p<0.05). The maximum blood flow rate of the left middle cerebral artery was significantly lower in Group 1 than in the control group (p<0.05). Conclusion: Minimum and maximum blood flow rates are significantly decreased in patients tilt test (+) patients with vasovagal syncope during orthostatic stress.

scholarly journals Effects of LI11 Acupuncture on CO2 reactivity in the anterior and middle cerebral arteries during hyperventilation-induced hypocapnia in normal subjects: A before and after study

2021 ◽  
Vol 42 (4) ◽  
pp. 174-185
Author(s):  
Gyeong-muk Kim ◽  
Woo-Sang Jung ◽  
Seungwon Kwon ◽  
Chul Jin ◽  
Seung-Yeon Cho ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Co2 Reactivity ◽  
Middle Cerebral Arteries ◽  
Before And After

Objectives: The LI11 (Quchi) acupuncture point has always been included in the Seven acupoints for stroke; however, additional LI11 acupuncture research is needed. In this study, the effect of LI11 acupuncture on cerebral blood flow of the anterior cerebral arteries (ACA) and middle cerebral arteries (MCA) was investigated.Method: This study included 10 healthy young male subjects. Cerebral blood flow velocity and cerebrovascular reactivity were measured using transcranial Doppler sonography. Changes in hyperventilation-induced carbon dioxide (CO2) reactivity and modified ACA and MCA blood flow velocity at 40 mmHg (CV40), blood pressure, and heart rate were observed before and after LI11 acupuncture treatment.Results: A statistically significant increase in contralateral anterior cerebral artery CO2 reactivity (p=0.036) and decrease in contralateral middle cerebral artery CV40 (p=0.047) were observed. No significant difference in mean blood pressure was shown. A statistically significant increase in heart rate occurred after LI11 acupuncture; however, it was not clinically significant as there were negligible changes in the heart rhythm.Conclusions: LI11 acupuncture treatment could improve cerebral blood flow velocity. These results might be explained by regulating endothelium-dependent vessel dilation in the anterior cerebral artery region.Trial registration: This trial has been registered with Clinical Research Information Service, a service of the Korea Centers for Disease Control and Prevention: KCT0004494 (retrospectively registered). https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=15359

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