scholarly journals Relative changes of cerebral arterial and venous blood volumes during increased cerebral blood flow: Implications for BOLD fMRI

2001 ◽  
Vol 45 (5) ◽  
pp. 791-800 ◽  
Author(s):  
Sang-Pil Lee ◽  
Timothy Q. Duong ◽  
Guang Yang ◽  
Costantino Iadecola ◽  
Seong-Gi Kim
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Venous Blood ◽  
Bold Fmri ◽  
Blood Volumes

scholarly journals Venous blood ammonia can be associated with cerebral blood flow in hepatic encephalopathy

Hepatology ◽  
2013 ◽  
Vol 58 (2) ◽  
pp. 832-833 ◽  
Author(s):  
Gang Zheng ◽  
Long Jiang Zhang ◽  
Yue Cao ◽  
Guang Ming Lu
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Hepatic Encephalopathy ◽  
Venous Blood ◽  
Blood Ammonia

scholarly journals The Contribution of Arterial Blood Gases in Cerebral Blood Flow Regulation and Fuel Utilization in Man at High Altitude

2015 ◽  
Vol 35 (5) ◽  
pp. 873-881 ◽  
Author(s):  
Christopher K Willie ◽  
David B MacLeod ◽  
Kurt J Smith ◽  
Nia C Lewis ◽  
Glen E Foster ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Cerebral Metabolism ◽  
Venous Blood ◽  
Blood Gases ◽  
Cerebrovascular Reactivity ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Cerebrovascular Function

The effects of partial acclimatization to high altitude (HA; 5,050 m) on cerebral metabolism and cerebrovascular function have not been characterized. We hypothesized (1) increased cerebrovascular reactivity (CVR) at HA; and (2) that CO2 would affect cerebral metabolism more than hypoxia. PaO2 and PaCO2 were manipulated at sea level (SL) to simulate HA exposure, and at HA, SL blood gases were simulated; CVR was assessed at both altitudes. Arterial–jugular venous differences were measured to calculate cerebral metabolic rates and cerebral blood flow (CBF). We observed that (1) partial acclimatization yields a steeper CO2-H+ relation in both arterial and jugular venous blood; yet (2) CVR did not change, despite (3) mean arterial pressure (MAP)-CO2 reactivity being doubled at HA, thus indicating effective cerebral autoregulation. (4) At SL hypoxia increased CBF, and restoration of oxygen at HA reduced CBF, but neither had any effect on cerebral metabolism. Acclimatization resets the cerebrovasculature to chronic hypocapnia.

scholarly journals Quantitative Measurements of Cerebral Blood Flow Using SPECT and [99mTc]-d,l-HM-PAO Compared to Xenon-133

1988 ◽  
Vol 8 (1_suppl) ◽  
pp. S69-S81 ◽  
Author(s):  
Allan R. Andersen ◽  
Hans H. Friberg ◽  
Jes F. Schmidt ◽  
Steen G. Hasselbalch
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Venous Blood ◽  
Clearance Ratio ◽  
Fick Principle ◽  
Quantitative Measurements ◽  
A Value ◽  
Basal Ganglia Disease ◽  
Xenon 133 ◽  
And Control

The uptake and retention in a 2 cm thick brain section was recorded serially by SPECT after i.v. injection of [99mTc]– d,l-HM-PAO (HM-PAO). In 16 patients, the fraction of the administered dose retained by the brain was 5.2 ± 1%, showing a peak after 40–50s, then decreasing by 10% within the first 10 min and then by only 0.4% per hour. The image contrast was measured in each patient as the regional hemispheric asymmetry difference in percent of the highest value of the two regions. It deceased from 31% at 30–40 s to 25% at 10 min. At 24 h, a value of 19% was reached. Using the images obtained at 10 min after injection, a region to region comparison of the original and corrected HM-PAO images to the xenon-133 regional cerebral blood flow (rCBF) images was performed. Forty-four patients with stroke, epilepsy, dementia, basal ganglia disease, and tumors and control subjects were included in this comparison. The algorithm proposed by Lassen et al. was used to correct the original images for back diffusion of tracer (brain to blood); a good correlation very close to the line of identity between the corrected HM-PAO and xenon-133 data was obtained when using a conversion/clearance ratio of 1.5 and when the noninvolved hemisphere was used as a reference region ( r = 0.86, p < 0.0001). Serial arterial and cerebral venous blood sampling was performed over 10 min following i.v. injection of HM-PAO in six patients. An overall brain retention fraction of 0.37 ± 0.03 (mean ± SEM) was calculated from the data. An average CBF of 0.62 ± 0.12 ml/g/min was determined on the basis of the Fick principle; this compared to a value of 0.59 ± 0.09 ml/g/min (mean ± SEM) measured by the xenon-133 inhalation method. The two sets of CBF values correlated linearly with a correlation coefficient of 0.97 ( p < 0.01). Inserting the average CBF value for the hemisphere as measured by the Fick principle into the algorithm described by Lassen et al. yields absolute rCBF values (ml/g/min) directly from the corrected HM-PAO images. We conclude that the xenon-133 inhalation method and [99mTc]– d,l-HM-PAO may supplement each other for SPECT studies of rCBF: xenon-133 inhalation for easy, repeatable, and quantitative measurements and [99mTc]– d,l-HM-PAO for high resolution static imaging in relative or absolute flow units.

scholarly journals Relations between BOLD fMRI-Derived Resting Brain Activity and Cerebral Blood Flow

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e44556 ◽  
Author(s):  
Zhengjun Li ◽  
Yisheng Zhu ◽  
Anna Rose Childress ◽  
John A. Detre ◽  
Ze Wang
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Activity ◽  
Bold Fmri

scholarly journals Interictal cortical hyperresponsiveness in migraine is directly related to the presence of aura

Cephalalgia ◽  
2013 ◽  
Vol 33 (6) ◽  
pp. 365-374 ◽  
Author(s):  
Ritobrato Datta ◽  
Geoffrey K Aguirre ◽  
Siyuan Hu ◽  
John A Detre ◽  
Brett Cucchiara
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Visual Stimulus ◽  
Visual Stimulation ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Visual Discomfort ◽  
Bold Fmri ◽  
Control Subjects ◽  
And Control

Objective The objective of this study was to compare the interictal cortical response to a visual stimulus between migraine with aura (MWA), migraine without aura (MwoA), and control subjects. Methods In a prospective case-control study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) was used to assess the response to a visual stimulus and arterial spin labeled perfusion MR to determine resting cerebral blood flow. A standardized questionnaire was used to assess interictal visual discomfort. Results Seventy-five subjects (25 MWA, 25 MwoA, and 25 controls) were studied. BOLD fMRI response to visual stimulation within primary visual cortex was greater in MWA (3.09 ± 0.15%) compared to MwoA (2.36 ± 0.13%, p = 0.0008) and control subjects (2.47 ± 0.11%, p = 0.002); responses were also greater in the lateral geniculate nuclei in MWA. No difference was found between MwoA and control groups. Whole brain analysis showed that increased activation in MWA was confined to the occipital pole. Regional resting cerebral blood flow did not differ between groups. MWA and MwoA subjects had significantly greater levels of interictal visual discomfort compared to controls ( p = 0.008 and p = 0.005, respectively), but this did not correlate with BOLD response. Conclusions Despite similar interictal symptoms of visual discomfort, only MWA subjects have cortical hyperresponsiveness to visual stimulus, suggesting a direct connection between cortical hyperresponsiveness and aura itself.

Effect of Liver Failure on the Cerebral Circulatory and Metabolic Responses to Hypoxia in the Goat

1976 ◽  
Vol 50 (1) ◽  
pp. 15-23
Author(s):  
N. N. Stanley ◽  
N. S. Cherniack
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Liver Failure ◽  
Venous Blood ◽  
Practical Importance ◽  
Critical Threshold ◽  
Threshold Values ◽  
Arterial O2 Saturation ◽  
O2 Delivery ◽  
The Brain

1. Six unanaesthetized goats were used to evaluate the effect of liver failure on the hypoxic responsiveness of cerebral blood flow. The animals breathed air and several different hypoxic gas mixtures enriched with sufficient CO2 to maintain an isocapnic state. The cerebral metabolic rate for O2 (CMRo2) was also measured in four of these goats. 2. In baseline studies there was a linear relationship between cerebral blood flow and arterial O2 saturation (Sa,o2) measured at different levels of isocapnic hypoxia. The slopes of the cerebral blood flow/Sa,o2 response lines were used to quantify the response of cerebral blood flow to hypoxia. In the healthy goat, CMRo2 was not depressed by hypoxia until the O2 tension (Po2) in arterial and cerebral venous blood had fallen below critical threshold values of approximately 3·2 and 2·2 kPa (24 and 16 mmHg) respectively. 3. Liver failure was accompanied by a fall in cerebral blood flow and CMRo2. There was also a depression in the response of cerebral blood flow to hypoxia and a disproportionate reduction of cerebral O2 delivery in hypoxia. CMRo2 was further reduced at arterial and cerebral venous Po2 values, which were much higher than the critical threshold values for producing hypoxic CMRo2 depression in health. 4. It is concluded that the brain becomes more vulnerable to the adverse effects of hypoxia during liver failure. This may be of practical importance in the management of patients with arterial hypoxaemia or other complications (e.g. anaemia or shock), which may reduce cerebral oxygen delivery.

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