Relevant bibliographies by topics / Dynamic Cerebral Autoregulation

Academic literature on the topic 'Dynamic Cerebral Autoregulation'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Dynamic Cerebral Autoregulation"

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Beishon, L., JS Minhas, R. Nogueira, P. Castro, C. Budgeon, M. Aries, S. Payne, TG Robinson, and RB Panerai. "INFOMATAS multi-center systematic review and meta-analysis individual patient data of dynamic cerebral autoregulation in ischemic stroke." International Journal of Stroke 15, no. 7 (February 24, 2020): 807–12. http://dx.doi.org/10.1177/1747493020907003.

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Rationale Disturbances in dynamic cerebral autoregulation after ischemic stroke may have important implications for prognosis. Recent meta-analyses have been hampered by heterogeneity and small samples. Aim and/or hypothesis The aim of study is to undertake an individual patient data meta-analysis (IPD-MA) of dynamic cerebral autoregulation changes post-ischemic stroke and to determine a predictive model for outcome in ischemic stroke using information combined from dynamic cerebral autoregulation, clinical history, and neuroimaging. Sample size estimates To detect a change of 2% between categories in modified Rankin scale requires a sample size of ∼1500 patients with moderate to severe stroke, and a change of 1 in autoregulation index requires a sample size of 45 healthy individuals (powered at 80%, α = 0.05). Pooled estimates of mean and standard deviation derived from this study will be used to inform sample size calculations for adequately powered future dynamic cerebral autoregulation studies in ischemic stroke. Methods and design This is an IPD-MA as part of an international, multi-center collaboration (INFOMATAS) with three phases. Firstly, univariate analyses will be constructed for primary (modified Rankin scale) and secondary outcomes, with key co-variates and dynamic cerebral autoregulation parameters. Participants clustering from within studies will be accounted for with random effects. Secondly, dynamic cerebral autoregulation variables will be validated for diagnostic and prognostic accuracy in ischemic stroke using summary receiver operating characteristic curve analysis. Finally, the prognostic accuracy will be determined for four different models combining clinical history, neuroimaging, and dynamic cerebral autoregulation parameters. Study outcome(s) The outcomes for this study are to determine the relationship between clinical outcome, dynamic cerebral autoregulation changes, and baseline patient demographics, to determine the diagnostic and prognostic accuracy of dynamic cerebral autoregulation parameters, and to develop a prognostic model using dynamic cerebral autoregulation in ischemic stroke. Discussion This is the first international collaboration to use IPD-MA to determine prognostic models of dynamic cerebral autoregulation for patients with ischemic stroke.
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Panerai, Ronney B. "Nonstationarity of dynamic cerebral autoregulation." Medical Engineering & Physics 36, no. 5 (May 2014): 576–84. http://dx.doi.org/10.1016/j.medengphy.2013.09.004.

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Secher, Niels H., and Johannes J. van Lieshout. "Dynamic Cerebral Autoregulation and Monitoring Cerebral Perfusion." Hypertension 56, no. 2 (August 2010): 189–90. http://dx.doi.org/10.1161/hypertensionaha.110.154971.

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Schondorf, Ronald, Reuben Stein, Richard Roberts, Julie Benoit, and William Cupples. "Dynamic cerebral autoregulation is preserved in neurally mediated syncope." Journal of Applied Physiology 91, no. 6 (December 1, 2001): 2493–502. http://dx.doi.org/10.1152/jappl.2001.91.6.2493.

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To test whether cerebral autoregulation is impaired in patients with neurally mediated syncope (NMS), we evaluated 15 normal subjects and 37 patients with recurrent NMS. Blood pressure (BP), heart rate, and cerebral blood velocity (CBV) (transcranial Doppler) were recorded at rest and during 80° head-up tilt (HUT). Static cerebral autoregulation as assessed from the change in cerebrovascular resistance during HUT was the same in NMS and controls. Properties of dynamic cerebral autoregulation were inferred from transfer gain, coherence, and phase of the relationship between BP and CBV estimated from filtered data segments (0.02–0.8 Hz). During the 3 min preceding syncope, dynamic cerebral autoregulation of subjects with NMS did not differ from that of controls nor did it change over the course of HUT in patients with NMS or in control subjects. Dynamic cerebral autoregulation was also unaffected by the degree of orthostatic intolerance as inferred from latency to onset of syncope. We conclude that cerebral autoregulation in patients with recurrent syncope does not differ from that of normal control subjects.
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Nishimura, Naoko, Ken-ichi Iwasaki, Yojiro Ogawa, and Ken Aoki. "Decreased steady-state cerebral blood flow velocity and altered dynamic cerebral autoregulation during 5-h sustained 15% O2 hypoxia." Journal of Applied Physiology 108, no. 5 (May 2010): 1154–61. http://dx.doi.org/10.1152/japplphysiol.00656.2009.

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Effects of hypoxia on cerebral circulation are important for occupational, high-altitude, and aviation medicine. Increased risk of fainting might be attributable to altered cerebral circulation by hypoxia. Dynamic cerebral autoregulation is reportedly impaired immediately by mild hypoxia. However, continuous exposure to hypoxia causes hyperventilation, resulting in hypocapnia. This hypocapnia is hypothesized to restore impaired dynamic cerebral autoregulation with reduced steady-state cerebral blood flow (CBF). However, no studies have examined hourly changes in alterations of dynamic cerebral autoregulation and steady-state CBF during sustained hypoxia. We therefore examined cerebral circulation during 5-h exposure to 15% O2 hypoxia and 21% O2 in 13 healthy volunteers in a sitting position. Waveforms of blood pressure and CBF velocity in the middle cerebral artery were measured using finger plethysmography and transcranial Doppler ultrasonography. Dynamic cerebral autoregulation was assessed by spectral and transfer function analysis. As expected, steady-state CBF velocity decreased significantly from 2 to 5 h of hypoxia, accompanying 2- to 3-Torr decreases in end-tidal CO2 (ETCO2). Furthermore, transfer function gain and coherence in the very-low-frequency range increased significantly at the beginning of hypoxia, indicating impaired dynamic cerebral autoregulation. However, contrary to the proposed hypothesis, indexes of dynamic cerebral autoregulation showed no significant restoration despite ETCO2 reductions, resulting in persistent higher values of very-low-frequency power of CBF velocity variability during hypoxia (214 ± 40% at 5 h of hypoxia vs. control) without significant increases in blood pressure variability. These results suggest that sustained mild hypoxia reduces steady-state CBF and continuously impairs dynamic cerebral autoregulation, implying an increased risk of shortage of oxygen supply to the brain.
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Schondorf, Ronald, Julie Benoit, and Reuben Stein. "Cerebral autoregulation is preserved in postural tachycardia syndrome." Journal of Applied Physiology 99, no. 3 (September 2005): 828–35. http://dx.doi.org/10.1152/japplphysiol.00225.2005.

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To test whether cerebral autoregulation is impaired in patients with postural tachycardia syndrome (POTS), we evaluated 17 healthy control subjects and 27 patients with POTS. Blood pressure, heart rate, and cerebral blood velocity (transcranial Doppler) were recorded at rest and during 80° head-up tilt (HUT). Static cerebral autoregulation, as assessed from the change in cerebrovascular resistance during HUT, was the same in POTS and in controls. The properties of dynamic cerebral autoregulation were inferred from transfer gain, coherence, and phase of the relationship between blood pressure and cerebral blood velocity estimated from filtered data segments (0.02–0.8 Hz). Dynamic cerebral autoregulation of patients with POTS did not differ from that of controls. The patients' dynamic cerebral autoregulation did not change over the course of HUT, despite increased tachycardia suggestive of worsening orthostatic stress. Inflation of military anti-shock trouser pants substantially reduced the tachycardia of patients with POTS without affecting cerebral autoregulation. Symptoms of orthostatic intolerance were reduced in one-half of the patients following military anti-shock trouser pants inflation. We conclude that cerebral perfusion and autoregulation in many patients with POTS do not differ from that of normal control subjects.
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Ogawa, Yojiro, Ken Aoki, Jitsu Kato, and Ken-ichi Iwasaki. "Differential effects of mild central hypovolemia with furosemide administration vs. lower body suction on dynamic cerebral autoregulation." Journal of Applied Physiology 114, no. 2 (January 15, 2013): 211–16. http://dx.doi.org/10.1152/japplphysiol.00741.2012.

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Diuretic-induced mild hypovolemia with hemoconcentration reportedly improves dynamic cerebral autoregulation, whereas central hypovolemia without hemoconcentration induced by lower body negative pressure (LBNP) has no effect or impairs dynamic cerebral autoregulation. This discrepancy may be explained by different blood properties, by degrees of central hypovolemia, or both. We investigated the effects of equivalent central hypovolemia induced by furosemide administration or LBNP application on dynamic cerebral autoregulation to test our hypothesis that mild central hypovolemia due to furosemide administration enhances dynamic cerebral autoregulation in contrast to LBNP. Seven healthy male subjects received 0.4 mg/kg furosemide and LBNP, with equivalent decreases in central venous pressure (CVP). Dynamic cerebral autoregulation was assessed by spectral and transfer function analysis between beat-to-beat mean arterial blood pressure (MAP) and mean cerebral blood flow velocity (MCBFV). CVP decreased by ∼3–4 mmHg with both furosemide administration (∼26 mg) and LBNP (approximately −20 mmHg). Steady state MCBFV remained unchanged with both techniques, whereas MAP increased significantly with furosemide administration. Coherence and transfer function gain in the low and high frequency ranges with hypovolemia due to furosemide administration were significantly lower than those due to LBNP (ANOVA interaction effects, P < 0.05), although transfer function gain in the very low frequency range did not change. Our results suggest that although the decreases in CVP were equivalent between furosemide administration and LBNP, the resultant central hypovolemia differentially affected dynamic cerebral autoregulation. Mild central hypovolemia with hemoconcentration resulting from furosemide administration may enhance dynamic cerebral autoregulation compared with LBNP.
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WHITE, R. P., P. VALLANCE, and H. S. MARKUS. "Effect of inhibition of nitric oxide synthase on dynamic cerebral autoregulation in humans." Clinical Science 99, no. 6 (November 21, 2000): 555–60. http://dx.doi.org/10.1042/cs0990555.

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Cerebral blood flow is maintained constant over a range of cerebral perfusion pressures by cerebral autoregulation. Impaired cerebral autoregulation may be important in the pathogenesis of cerebral ischaemia. The mechanisms mediating normal cerebral autoregulation in humans are poorly understood. We used a recently described transcranial Doppler technique, which allows non-invasive measurement of dynamic cerebral autoregulation, to test the hypothesis that nitric oxide mediates cerebral autoregulation. The rate of rise of middle cerebral artery blood flow velocity, compared with that of arterial blood pressure, was determined following a stepwise fall in arterial blood pressure, in order to calculate an autoregulatory index. The effect of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) on dynamic autoregulation was compared with that of noradrenaline titrated to result in a similar rise in blood pressure. Six healthy subjects were studied in each group. The mean (S.D.) change in autoregulatory index following noradrenaline at a similar pressor dose was significantly greater than the change following the L-NMMA bolus: 1.1 (1.2) compared with -0.8 (0.8) for the left middle cerebral artery (P = 0.002), and 1.1 (0.8) compared with -0.8 (0.8) for the right middle cerebral artery (P = 0.002). There was no difference in the mean (S.D.) blood pressure increase resulting from the two agents: L-NMMA, 19.7 (7.4) mmHg; noradrenaline, 15.5 (4.8) mmHg (P = 0.281). These results suggest that nitric oxide mediates at least part of the dynamic phase of cerebral autoregulation in humans. Reduced nitric oxide release may play a role in the impaired cerebral autoregulation seen in patients with, or at risk of, cerebral ischaemia.
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Parthasarathy, Ashwin B., Kimberly P. Gannon, Wesley B. Baker, Christopher G. Favilla, Ramani Balu, Scott E. Kasner, Arjun G. Yodh, John A. Detre, and Michael T. Mullen. "Dynamic autoregulation of cerebral blood flow measured non-invasively with fast diffuse correlation spectroscopy." Journal of Cerebral Blood Flow & Metabolism 38, no. 2 (December 12, 2017): 230–40. http://dx.doi.org/10.1177/0271678x17747833.

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Cerebral autoregulation (CA) maintains cerebral blood flow (CBF) in the presence of systemic blood pressure changes. Brain injury can cause loss of CA and resulting dysregulation of CBF, and the degree of CA impairment is a functional indicator of cerebral tissue health. Here, we demonstrate a new approach to noninvasively estimate cerebral autoregulation in healthy adult volunteers. The approach employs pulsatile CBF measurements obtained using high-speed diffuse correlation spectroscopy (DCS). Rapid thigh-cuff deflation initiates a chain of responses that permits estimation of rates of dynamic autoregulation in the cerebral microvasculature. The regulation rate estimated with DCS in the microvasculature (median: 0.26 s−1, inter quartile range: 0.19 s−1) agrees well (R = 0.81, slope = 0.9) with regulation rates measured by transcranial Doppler ultrasound (TCD) in the proximal vasculature (median: 0.28 s−1, inter quartile range: 0.10 s−1). We also obtained an index of systemic autoregulation in concurrently measured scalp microvasculature. Systemic autoregulation begins later than cerebral autoregulation and exhibited a different rate (0.55 s−1, inter quartile range: 0.72 s−1). Our work demonstrates the potential of diffuse correlation spectroscopy for bedside monitoring of cerebral autoregulation in the microvasculature of patients with brain injury.
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Elting, Jan Willem J., Jeanette Tas, Marcel JH Aries, Marek Czosnyka, and Natasha M. Maurits. "Dynamic cerebral autoregulation estimates derived from near infrared spectroscopy and transcranial Doppler are similar after correction for transit time and blood flow and blood volume oscillations." Journal of Cerebral Blood Flow & Metabolism 40, no. 1 (October 24, 2018): 135–49. http://dx.doi.org/10.1177/0271678x18806107.

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We analysed mean arterial blood pressure, cerebral blood flow velocity, oxygenated haemoglobin and deoxygenated haemoglobin signals to estimate dynamic cerebral autoregulation. We compared macrovascular (mean arterial blood pressure-cerebral blood flow velocity) and microvascular (oxygenated haemoglobin-deoxygenated haemoglobin) dynamic cerebral autoregulation estimates during three different conditions: rest, mild hypocapnia and hypercapnia. Microvascular dynamic cerebral autoregulation estimates were created by introducing the constant time lag plus constant phase shift model, which enables correction for transit time, blood flow and blood volume oscillations (TT-BF/BV correction). After TT-BF/BV correction, a significant agreement between mean arterial blood pressure-cerebral blood flow velocity and oxygenated haemoglobin-deoxygenated haemoglobin phase differences in the low frequency band was found during rest (left: intraclass correlation=0.6, median phase difference 29.5° vs. 30.7°, right: intraclass correlation=0.56, median phase difference 32.6° vs. 39.8°) and mild hypocapnia (left: intraclass correlation=0.73, median phase difference 48.6° vs. 43.3°, right: intraclass correlation=0.70, median phase difference 52.1° vs. 61.8°). During hypercapnia, the mean transit time decreased and blood volume oscillations became much more prominent, except for very low frequencies. The transit time related to blood flow oscillations was remarkably stable during all conditions. We conclude that non-invasive microvascular dynamic cerebral autoregulation estimates are similar to macrovascular dynamic cerebral autoregulation estimates, after TT-BF/BV correction is applied. These findings may increase the feasibility of non-invasive continuous autoregulation monitoring and guided therapy in clinical situations.
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Dissertations / Theses on the topic "Dynamic Cerebral Autoregulation"

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Haunton, Victoria Joanna. "Is dynamic cerebral autoregulation impaired in idiopathic Parkinson's disease?" Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28752.

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Background: Cerebral autoregulation (CA) refers to the ability of the brain to maintain a relatively constant cerebral blood flow (CBF) in response to significant changes in cerebral perfusion pressure. CA is governed by several key mechanisms, which can be described as neurogenic, myogenic and metabolic. Idiopathic Parkinson’s disease (PD) is a common neurodegenerative disease with a significant autonomic component, and it has been hypothesised that CA in PD may therefore be impaired. However, to date, the literature on this subject has been limited in its scope, of uneven quality and has yielded conflicted findings. Objective: This Thesis aimed to determine if dynamic CA is impaired in patients with idiopathic PD, compared to healthy control subjects, and if dynamic CA varies between the ‘on’ and ‘off’ states of PD. Methods: CA was assessed by means of continuous non-invasive monitoring of arterial blood pressure (BP) and velocities in the middle cerebral arteries bilaterally using transcranial Doppler ultrasound. A cohort of patients with idiopathic Parkinson’s disease were studied in both their clinically ‘on’ and ‘off’ states, and their data were compared to that obtained from age- and sex-matched healthy controls. In addition to assessing the CA response to spontaneous fluctuations in BP, a variety of paradigms were used to induce changes in mean cerebral blood flow velocity and BP, including passive arm movement and hyperventilation. Results: This study has demonstrated that CA responses to spontaneous fluctuations in BP do not differ significantly between the on and off states of PD, but do differ significantly between PD patients and healthy controls, ultimately suggesting that CA is altered, but not necessarily impaired, in idiopathic PD. CBF velocity responses to passive arm movement and hyperventilation did not differ significantly between the on and off states of PD, or between PD patients and healthy controls.
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Krishnamurthy, Shantha Arcot. "CARDIO-RESPIRATORY INFLUENCE ON DYNAMIC CEREBRAL AUTOREGULATION DURING HEAD UP TILT MEDIATED PRESYNCOPE." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/196.

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Altered cerebral hemodynamics contributes to mechanisms of unexplained syncope. Wecompared dynamic interaction between respiration and cerebral autoregulation in two groups ofsubjects from 28 healthy adults. Based on development of tilt-induced presyncope, subjects wereclassified as Non-Presyncopals (n=23) and Presyncopals (n=5). Airflow, CO2, Doppler cerebralblood flow velocity (CBF), ECG and blood pressure (BP) were recorded. To determine whetherinfluences of mean BP (MBP) and systolic BP (SBP) on CBF were altered in Presyncopals, thecoherencies and transfer functions between these variables and mean and peak CBF (CBFm andCBFp) were estimated. To determine influence of end-tidal CO2 (ETCO2) on CBF, relative CO2reactivity was calculated. The two primary findings were, during tilt in Presyncopals: (1) Inrespiratory frequency region, coherence between SBP and CBFp (p=0.02) and transfer functiongain between BP and CBFm was higher (MBP, p=0.01, and SBP, p=0.01) than in Non-Presyncopals. (2) In the last 3 minutes prior to presyncope, Presyncopals had a reduced relativeCO2 reactivity (p=0.005). Thus the relationship of CBF with systemic BP was more pronouncedor cerebral autoregulation was less effective preceding presyncope. This decreasedautoregulation, secondary to decreased ETCO2, may contribute in the cascade of events leadingto unexplained syncope.
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Moore, Stephen Michael. "Computational 3D Modelling of Hemodynamics in the Circle of Willis." Thesis, University of Canterbury. Mechanical Engineering, 2007. http://hdl.handle.net/10092/1168.

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The Circle of Willis (CoW) is a ring-like arterial structure forming the major anastomotic connection between arterial supply systems in the brain, and is responsible for the distribution of oxygenated blood throughout the cerebral mass. Among the general population, only approximately 50% have a complete CoW, where absent or hypoplastic vessels are common among a multitude of possible anatomical variations, reducing the degree to which blood may be rerouted. While an individual with one of these variations may under normal circumstances suffer no ill effects, there are certain pathological conditions which can present a risk to the person's health and increase the possibility of suffering an ischaemic stroke when compounded with an anatomical variation. This body of work presents techniques for generating 3D models of the cerebral vasculature using magnetic resonance imaging (MRI) and performing computational fluid dynamics (CFD) simulations in order to simulate the flow patterns throughout a circle of Willis. Incorporated with the simulations is a mathematical model of the cerebral autoregulation mechanism, simulating the ability of the smaller arteries and arterioles in the brain to either constrict or dilate in response to alterations in cerebral blood flow, thereby altering the cerebrovascular resistance of each major brain territory and regulating the amount of blood flow within a physiological range of cerebral perfusion pressure. The CFD simulations have the ability to predict the amount of collateral flow rerouted via the communicating arteries in response to a stenosis or occlusion, and the major objective of this study has been the investigation of how anatomical variations of the circle of Willis affect the capacity to provide this collateral flow. Initial work began with the development of three idealized models of common anatomical variations, created using computer aided design software (CAD) and based on the results of MRI scans. The research then shifted to developing a technique whereby patient specific models of the circle of Willis could be directly segmented from the MRI data. As a result of this shift, an interactive GUI-based tool was developed for the processing of the MRI datasets, allowing for rapid data enhancement and creation of a surface topology representing the arterial wall of the circle of Willis, suitable for a CFD simulation. The results of both sets of simulations illustrate that there exist a number of variables associated with a patients circle of Willis geometry, such as cerebral blood flow and combinations and degrees of stenosis, implying that the initial goal of drawing generalized conclusions was perhaps flawed. Instead, a crucial outcome of this body of work is that the future research should be directed toward extending the physiological complexity of both the geometry and the autoregulation model, with the intention of a patient specific application rather than producing large datasets with which to make broad generalizations.
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Jiang, Zong-Xun, and 江宗勳. "The Assessment of Dynamic Cerebral Autoregulation in Diabetes Using Linear Analysis." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/d2q2ca.

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碩士
逢甲大學
自動控制工程所
90
Abstract In recent years, stroke is the third leading cause of mortality in Taiwan. One of the most important factors contributing to stroke is the regulation of cerebral blood flow (CBF) which is influenced by cerebral autoregulation (CA). Most of clinical instruments for detecting CBF (such as MRI, PET) are very expensive and not suitable for continuous movement. In this study, the arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) were continuously measured by Finapres and transcranial Doppler (TCD) respectively during the supine and tilt-up positions. The mean arterial blood pressure (MABP) and mean cerebral blood flow velocity (MCBFV) time series were calculated. Ten healthy adults, ten diabetes without autonomic neuropathy, and ten with autonomic neuropathy (sex and age matched) were examined in this study. The CA model was analyzed by linear analysis in time-domain, frequency-domain and time-frequency domain of clinical real-time data of ABP and CBF. The main purpose of this study is to use noninvasive and signal processing techniques to observe the fluctuations between the ABP and CBFV. The results of time-domain analysis show that MABP of diabetic autonomic neuropathy (DAN) (supine：91.55□14.85 mmHg, tilt-up：74.12□13.35 mmHg) decrease significantly during tilt-up than that of healthy adults (supine：88.83□9.17 mmHg, tilt-up：93.97□11.39 mmHg). In addition, the results of cluster analysis based on distance measurement using the scattered plot between MABP and MCBFV show that DAN (supine－tilt-up mean：20.00□6.22, tilt-up－supine mean：20.10□6.09, supine mean－tilt-up mean：19.71□6.17) larger than healthy adults (supine－tilt-up mean：12.45□6.00, tilt-up－supine mean：12.66□5.70, supine mean－tilt-up mean：10.88□7.00). To observe the results of autoregulation curve analysis, the slope of DAN (slope between supine mean－tilt-up mean：1.34□2.66) also larger than healthy adults (slope between supine mean－tilt-up mean：0.87□0.15). Finally, the results of frequency-domain analysis show that the fluctuations of DAN both in MABP and MCBFV are significantly smaller than that of healthy adults. It can obtain similar results form other linear analysis. Linear analysis exhibits significantly different between healthy adults and DAN. The results are helpful for clinical practice and can provide critical information for physicians. Keywords：cerebral autoregulation, noninvasive, linear analysis
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Chou, Chih-Che, and 周志哲. "Assessment of Dynamic Cerebral Autoregulation Using Resting Blood Oxygenation Level Dependent Based Functional MRI." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/12546992994835323800.

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碩士
國立陽明大學
放射醫學科學研究所
94
Purpose: Dynamic cerebral auto-regulation (DCA) is a key ingredient in functional magnetic resonance imaging (fMRI) studies based on blood oxygenation level dependent (BOLD) response. The delay time estimation by cross-spectral analysis between the physiological signals such as the relation between cerebral blood flow (CBF) and arterial blood pressure (aBP) has been widely used as an index of DCA mechanism. By simultaneous recording of the physiological activities during fMRI acquisition, we can detect and quantify spontaneous fluctuations in BOLD signals and link up these fluctuations with DCA mechanism. Materials and Methods: Eight subjects were recruited for 5-min resting fMRI scan in a 3.0 Tesla system using a single-slice echo planar imaging sequence. Heart beat, respiration, and aBP were simultaneously monitored during data acquisition. The delay time between BOLD and physiological signals was investigated by using cross-spectral analysis including coherence function and phase spectra. On the basis of phase spectra with the significant coherence in the each frequency range, phase delays were evaluated as arriving time delays between them in the observed slice. Group delay can be calculated by the slope of best-fit regression line in the estimated phase spectra. Results: Our results are in line with previous findings from the signals of aBP or CBF, and found that inherent BOLD resting fluctuations comprising very low frequency (VLF, less than 0.04 Hz), low frequency (LF, 0.04 to 0.15 Hz), respiratory component, so called high frequency (HF, 0.15 to 0.4 Hz), and first plus second harmonic peak of heart rate in all subjects. The BOLD resting rhythms are spatially consistent across subjects and distribute close to blood vessels, sinus and cerebral spinal fluid pools regions. High coherence in the LF, HF, and heart rate (> 0.5), but it was not the case for the VLF component. Inconsistent phase delays in the each frequency range between the pixels were observed in the phase spectra. For further linear regression analysis, The r values in the HF and cardiac ranges with significant coherences were fair (r = 0.02 ± 0.08 and 0.08 ± 0.31; mean ± standard deviation). A high r value in the LF range (r = -0.58 ± 0.08) suggested the LF fluctuations in the BOLD signals lag behind those in aBP signals about 1.89 ± 0.62 seconds. Conclusion: Cross-spectrum analysis provides a good relation between BOLD and aBP signals along each frequency ranges. First, high coherence except VLF range (> 0.5) indicates great similarity between BOLD and pressure signals. Second, inconsistent phase delays between the pixels imply that the physiological signals may be mixed in a convolutive manner with non-zero delay. Third, group delay in the estimated phase spectra revealed a good frequency-dependent relationship in the LF range only, and LF fluctuations in the BOLD signals lagged behind those in aBP signals about 1.89 ± 0.62 seconds. We conclude that group delay from BOLD-pressure relation in the LF range may carry information on non-invasively assessing spatial distribution of focal DCA mechanism in adult brain.
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Tsai, Yu-Chou, and 蔡育周. "Using Nonlinear Analysis for Assessment of Dynamic Cerebral Autoregulation in Diabetes with Autonomic Neuropathy." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/x594mt.

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碩士
逢甲大學
自動控制工程所
91
The cerebral autoregulation (CA) mechanism refers to the cerebral blood flow (CBF) tendency to maintain relatively constant in the brain despite changes in mean arterial blood pressure (MABP). The main purpose of this study is to use chaotic analysis approaches to analyze the blood pressure and cerebral blood flow between 11 age-matched normal subjects and 19 diabetics with autonomic neuropathy. MABP in the finger via Finapres and mean cerebral blood flow velocity (MCBFV) of the middle cerebral artery via transcranial doppler (TCD) ultrasound were measured continuously during supine and tilt-up positions each for 5 minutes in both normals and patients. The results showed that the correlation dimension (CD) values of MABP in diabetics subjects (MABP supine: 3.688±2.289; MABP tilt-up: 2.145±1.239; p<0.01, paired t-test) decreased with statistical significance between supine and tilt-up positions. On the other hand, CD values of MABP between normals and patients in supine position (MABP in normals: 2.012±0.775; MABP in patients: 3.688±2.289; p<0.05) were significantly different. The CD of MCBFV remained no change. The Lyapunov exponent (LE) in MABP between normals and patinents in supine position (Normals: 1.704±0.995; Patients: 1.016±0.415; p<0.05) and MCBFV in patients between supine and tilt-up positions (Supine: 1.058±0.333; Tilt-up: 0.797±0.382; p<0.05) were different with statistical significance. The Kolmogorov entropy (K2) values in both the normal subjects and diabetics were not statistically significant. The only difference is that the K2 values of MCBFV between normals and diabetics in tilt-up positions were significantly different (Normals: 2.835±0.461, Patients: 3.323±0.568; p<0.05). It can be concluded that the CD, LE, and K2 nonlinear measures are suitable tools to explore the nonlinear analysis of dynamic CA.
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Book chapters on the topic "Dynamic Cerebral Autoregulation"

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Levine, Benjamin D., Rong Zhang, and Robert C. Roach. "Dynamic Cerebral Autoregulation at High Altitude." In Advances in Experimental Medicine and Biology, 319–22. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4711-2_24.

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Turova, Varvara, Nikolai Botkin, Ana Alves-Pinto, Tobias Blumenstein, Esther Rieger-Fackeldey, and Renée Lampe. "Modeling Autoregulation of Cerebral Blood Flow Using Viability Approach." In Advances in Dynamic and Mean Field Games, 345–63. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70619-1_16.

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Chacón, Max, Cristopher Blanco, Ronney Panerai, and David Evans. "Nonlinear Modeling of Dynamic Cerebral Autoregulation Using Recurrent Neural Networks." In Lecture Notes in Computer Science, 205–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11578079_22.

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Chacón, Max, Darwin Diaz, Luis Ríos, David Evans, and Ronney Panerai. "Support Vector Machine with External Recurrences for Modeling Dynamic Cerebral Autoregulation." In Lecture Notes in Computer Science, 954–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11892755_99.

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Chacón, Max, Sun-Ho Noh, Jean Landerretche, and José L. Jara. "Comparing Models of Spontaneous Variations, Maneuvers and Indexes to Assess Dynamic Cerebral Autoregulation." In Acta Neurochirurgica Supplement, 159–62. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-65798-1_33.

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Ortega-Gutierrez, S., E. A. Samaniego, A. Reccius, A. Huang, B. Zheng-Lin, A. Masukar, R. S. Marshall, and N. H. Petersen. "Changes on Dynamic Cerebral Autoregulation Are Associated with Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage." In Acta Neurochirurgica Supplement, 149–53. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-04615-6_22.

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Jara, José L., Nazia P. Saeed, Ronney B. Panerai, and Thompson G. Robinson. "Increasing the Contrast-to-Noise Ratio of MRI Signals for Regional Assessment of Dynamic Cerebral Autoregulation." In Acta Neurochirurgica Supplement, 153–57. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-65798-1_32.

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Tanaka, Kortaro, Yasuo Fukuuchi, Toshitaka Shirai, Shigeru Nogawa, Hiroyuki Nozaki, Eiichiro Nagata, Taro Kondo, Satoshi Koyama, and Tomohisa Dembo. "Role of Nitric Oxide in Autoregulation of Cerebral Blood Flow in the Rat." In Oxygen Homeostasis and Its Dynamics, 609–15. Tokyo: Springer Japan, 1998. http://dx.doi.org/10.1007/978-4-431-68476-3_79.

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Liu, J., D. M. Simpson, and R. Allen. "Tracking the Dynamics of the Cerebral Autoregulation Response to Sudden Changes of PaCO2." In IFMBE Proceedings, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03882-2_1.

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Conference papers on the topic "Dynamic Cerebral Autoregulation"

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Kostoglou, Kyriaki, Alexander D. Wright, Jonathan D. Smirl, Kelsey Bryk, Paul van Donkelaar, and Georgios D. Mitsis. "Dynamic cerebral autoregulation in young athletes following concussion." In 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2016. http://dx.doi.org/10.1109/embc.2016.7590797.

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Kainerstorfer, Jana M., Angelo Sassaroli, Kristen T. Tgavalekos, and Sergio Fantini. "Dynamic cerebral autoregulation measured with coherent hemodynamics spectroscopy (CHS)." In SPIE BiOS, edited by Bruce J. Tromberg, Arjun G. Yodh, Eva M. Sevick-Muraca, and Robert R. Alfano. SPIE, 2015. http://dx.doi.org/10.1117/12.2077816.

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Manikandan, S., Arulvelan A., and Ramesh Rathod. "Dynamic cerebral autoregulation following loading dose of Dexmedetomidine; A transcranial doppler study." In 15th Annual Conference of the Indian Society of Neuroanaesthesiology and Critical Care. Thieme Medical and Scientific Publishers Private Ltd., 2015. http://dx.doi.org/10.1055/s-0038-1667527.

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Olufsen, Mette S., Lewis A. Lipsitz, and Ali Nadim. "A Lumped Parameter Model for Cerebral Blood Flow Regulation." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23138.

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Abstract Dynamic changes in cerebral blood flow and the associated vascular responses accompanying posture change that enable the brain to maintain perfusion during hypotensive stress are not fully understood. The aim of this work is to use a lumped parameter model of cerebral blood flow to analyze changes in key parameters (systemic and cerebrovascular resistances) during posture change from sitting to standing. Such a model sheds light on vascular adaptation to hypotensive stress, and could ultimately help determine the changes in cerebral autoregulation that occur in aging, hypertension, and other clinical conditions.
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Ruesch, Alexander, Jason Yang, Deepshikha Acharya, Samantha Schmitt, Matthew A. Smith, and Jana M. Kainerstorfer. "Comparison of Dynamic and Static Assessment of Cerebral Autoregulation in Non-Human Primates." In Optical Tomography and Spectroscopy. Washington, D.C.: OSA, 2020. http://dx.doi.org/10.1364/ots.2020.stu2d.3.

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Selb, Juliette, Susanne Muehlschlegel, Solomon G. Diamond, Maria Angela Franceschini, Lee H. Schwamm, and David A. Boas. "Disruption of Dynamic Cerebral Autoregulation in Ischemic Stroke Patients Assessed by Continuous-Wave NIRS." In Biomedical Optics. Washington, D.C.: OSA, 2008. http://dx.doi.org/10.1364/biomed.2008.bsud4.

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Tian, Fenghua, Takashi Tarumi, Hanli Liu, Rong Zhang, and Lina Chalak. "Assessment of Dynamic Cerebral Autoregulation in Neonatal Hypoxic-Ischemic Encephalopathy Based on Wavelet Transform Coherence." In Cancer Imaging and Therapy. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/cancer.2016.jw3a.36.

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Furian, M., M. Ulliel-Roche, C. A. Howe, F. Zerizer, M. Marillier, A. Bernard, I. Hancco, et al. "Comparison of dynamic cerebral autoregulation and cardiac baroreceptor sensitivity between residents living at different altitudes." In ERS International Congress 2022 abstracts. European Respiratory Society, 2022. http://dx.doi.org/10.1183/13993003.congress-2022.1073.

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Mahmic, Alma, Fatimah Ibrahim, and Maw Pin Tan. "Mathematical frameworks to assess the dynamics of cerebral autoregulation." In 2012 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES 2012). IEEE, 2012. http://dx.doi.org/10.1109/iecbes.2012.6498186.

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Parthasarathy, Ashwin B., Kimberly Gannon, Wesley B. Baker, Venki Kavuri, Michael T. Mullen, John A. Detre, and Arjun G. Yodh. "Cerebral Autoregulation Dynamics with High-Speed Diffuse Correlation Spectroscopy." In Optics and the Brain. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/brain.2016.bth4d.7.

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Reports on the topic "Dynamic Cerebral Autoregulation"

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Wang, Kai, Zhiguo Lv, Peng Xu, Baitong Wang, Aanqi Hou, Tianye Lan, Dongmei Zhang, and Jian Wang. Relevance of dynamic cerebral autoregulation after acute ischemic stroke with prognosis: A protocol for systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, January 2022. http://dx.doi.org/10.37766/inplasy2022.1.0056.

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