scholarly journals Time delay processing of hypercapnic fMRI allows quantitative parameterization of cerebrovascular reactivity and blood flow delays

2016 ◽  
Vol 36 (10) ◽  
pp. 1767-1779 ◽  
Author(s):  
Manus J Donahue ◽  
Megan K Strother ◽  
Kimberly P Lindsey ◽  
Lia M Hocke ◽  
Yunjie Tong ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cross Correlation ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Intracranial Stenosis ◽  
Peak Time ◽  
Surgical Revascularization ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
The Brain

Blood oxygenation level-dependent fMRI contrast depends on the volume and oxygenation of blood flowing through the circulatory system. The effects on image intensity depend temporally on the arrival of blood within a voxel, and signal can be monitored during the time course of such blood flow. It has been previously shown that the passage of global endogenous variations in blood volume and oxygenation can be tracked as blood passes through the brain by determining the strength and peak time lag of their cross-correlation with blood oxygenation level-dependent data. By manipulating blood composition using transient hypercarbia and hyperoxia, we can induce much larger oxygenation and volume changes in the blood oxygenation level-dependent signal than result from natural endogenous fluctuations. This technique was used to examine cerebrovascular parameters in healthy subjects (n = 8) and subjects with intracranial stenosis (n = 22), with a subgroup of intracranial stenosis subjects scanned before and after surgical revascularization (n = 6). The halfwidth of cross-correlation lag times in the brain was larger in IC stenosis subjects (21.21 ± 14.22 s) than in healthy control subjects (8.03 ± 3.67), p < 0.001, and was subsequently reduced in regions that co-localized with surgical revascularization. These data show that blood circulatory timing can be measured robustly and longitudinally throughout the brain using simple respiratory challenges.

scholarly journals Anatomical, blood oxygenation level-dependent, and blood flow MRI of nonhuman primate (baboon) retina

2011 ◽  
Vol 66 (2) ◽  
pp. 546-554 ◽  
Author(s):  
Yi Zhang ◽  
Hsiao-Ying Wey ◽  
Oscar San Emeterio Nateras ◽  
Qi Peng ◽  
Bryan H. De La Garza ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nonhuman Primate ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Flow Mri

scholarly journals Quantitative aspects of brain perfusion dynamic induced by BOLD fMRI

2006 ◽  
Vol 64 (4) ◽  
pp. 895-898 ◽  
Author(s):  
Katia C. Andrade ◽  
Octavio M. Pontes-Neto ◽  
Joao P. Leite ◽  
Antonio Carlos Santos ◽  
Oswaldo Baffa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Grey Matter ◽  
Brain Perfusion ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Breath Holding ◽  
Bold Signal ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Dependent Signal

The increase of relative cerebral blood flow (rCBF) may contribute for a change in blood oxygenation level dependent signal (BOLD). The main purpose of this study is to investigate some aspects of perfusional alterations in the human brain in response to a uniform stimulation: hypercapnia induced by breath holding. It was observed that the BOLD signal increased globally during hypercapnia and that it is correlated with the time of breath holding. This signal increase shows a clear distinction between gray and white matter, being greater in the grey matter.

The Effect of Esmolol on Cerebral Blood Flow, Cerebral Vasoreactivity, and Cognitive Performance: A Functional Magnetic Resonance Imaging Study

2005 ◽  
Vol 102 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Wolfgang Heinke ◽  
Stefan Zysset ◽  
Margret Hund-Georgiadis ◽  
Derk Olthoff ◽  
D Yves von Cramon
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Magnetic Resonance Imaging ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygenation Level ◽  
Oxygenation Level

Background Esmolol is often applied perioperatively to maintain stable hemodynamic conditions in neurosurgical patients. Little is known, however, about its effects on cerebral circulation. The authors employed functional magnetic resonance imaging based on blood oxygenation level-dependent contrast to explore the effect of esmolol on the human brain. The purpose of the study was to investigate the effect of esmolol on cerebral blood flow, cerebral vasoreactivity, and cognitive performance. Methods Ten healthy volunteers were investigated in two separate experimental sessions using functional magnetic resonance imaging. During the first experimental session, a hyperventilation task and a cognitive task, subjects had to perform both tasks twice, once after administration of an esmolol bolus of 1 mg/kg followed by a continuous infusion of 150 microg.kg.min and once without beta-blockade, in a random order. During the second experimental session subjects were scanned at resting state after administration of esmolol. Furthermore, the effect of the esmolol dose on hemodynamic changes caused by beta-adrenergic stimulation with orciprenaline was investigated. Results Esmolol decreased heart rate and blood pressure during the various experimental conditions and blunted the increase in heart rate and blood pressure caused by orciprenaline. Infusion of esmolol affects neither the blood oxygenation level-dependent contrast during the functional challenges nor the reaction times during the cognitive task. However, the esmolol bolus caused a brief blood oxygenation level-dependent contrast increase. Conclusion The results indicate that effective beta-blockade with esmolol does not affect cerebral blood flow, cerebrovascular reactivity, or cognitive performance.

scholarly journals Effects of aging on cerebral blood flow, oxygen metabolism, and blood oxygenation level dependent responses to visual stimulation

2009 ◽  
Vol 30 (4) ◽  
pp. 1120-1132 ◽  
Author(s):  
Beau M. Ances ◽  
Christine L. Liang ◽  
Oleg Leontiev ◽  
Joanna E. Perthen ◽  
Adam S. Fleisher ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Visual Stimulation ◽  
Oxygen Metabolism ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Effects Of Aging

scholarly journals Cerebrovascular blood oxygenation level dependent pulsatility at baseline and following acute exercise among healthy adolescents

2018 ◽  
Vol 39 (9) ◽  
pp. 1737-1749 ◽  
Author(s):  
Athena E Theyers ◽  
Benjamin I Goldstein ◽  
Arron WS Metcalfe ◽  
Andrew D Robertson ◽  
Bradley J MacIntosh
Keyword(s):  
Acute Exercise ◽  
Physiological Stress ◽  
Blood Oxygenation Level Dependent ◽  
Blood Oxygenation ◽  
Moderate Intensity ◽  
Efficient Detection ◽  
Blood Oxygenation Level ◽  
Oxygenation Level ◽  
Repetition Time ◽  
The Brain

Arterial stiffness is linked to cerebral small vessel damage and neurodegeneration, but barriers to accessing deep cerebrovascular anatomy limit our ability to assess the brain. This study describes an adaptation of a cardiac-related scrubbing method as a means of generating blood oxygenation level-dependent pulsatility maps based on the cardiac cycle. We examine BOLD pulsatility at rest, based on the non-parametric deviation from null metric, as well as changes following acute physiological stress from 20 min of moderate-intensity cycling in 45 healthy adolescents. We evaluate the influence of repetition time (TR) and echo time (TE) using simulated and multi-echo empirical data, respectively. There were tissue-specific and voxel-wise BOLD pulsatility decreases 20 min following exercise cessation. BOLD pulsatility detection was comparable over a range of TR and TE values when scan volumes were kept constant; however, short TRs (≤500 ms) and TEs (∼14 ms) acquisitions would yield the most efficient detection. Results suggest cardiac-related BOLD pulsatility may represent a robust and easily adopted method of mapping cerebrovascular pulsatility with voxel-wise resolution.

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