TY - JOUR. T1 - Temporal lobe seizure interhemispheric propagation time depends on nonepileptic cortical cerebral blood flow. AU - Weinand, M. E.. AU - Labiner, D. M.. AU - Ahern, G. L.. PY - 2001/3/24. Y1 - 2001/3/24. N2 - In some patients with epilepsy, activation of eloquent cortex using various forms of environmental stimulation and mental activity may induce seizures. The increased neuronal activity resulting from cortical stimulation may be associated with increased regional cerebral blood flow. The vascular steal theory of temporal lobe epilepsy suggests that as nonepileptogenic cortical cerebral blood flow (CBFn) increases, temporal lobe epileptogenicity increases as a result, in part, of decreasing interhemispheric propagation time (IHPT). Recently, IHPT has been shown to be a quantitative electrocorticographic measure of temporal lobe epileptogenicity. In the current study, long-term combined subdural-EEG and surface cortical cerebral blood flow (CBF) monitoring was performed to test ...
article{3b545620-2f5d-4405-9964-2753884aaa8d, abstract = {The effect of moderate hypoglycaemia (venous blood glucose 2.0 +/- 0.2 mmol/l; mean +/- SD) on regional cerebral blood flow and cerebral volume was studied in a group of ten right-handed patients with Type 1 (insulin-dependent) diabetes mellitus (age 26.0 +/- 2.4 years, duration 18.4 +/- 3.8 years) using an intravenous Xenon 133 single photon emission computed tomography technique. After 10 min of hypoglycaemia, global cerebral blood flow had increased to 55.8 +/- 4.5 ml.100 g-1.min-1 compared to the initial normoglycaemic flow of 49.5 +/- 3.7 ml.100 g-1.min-1 (p < 0.01). A further increase in global cerebral blood flow to 59.5 +/- 4.5 ml.100 g-1.min-1 (p < 0.05) occurred 15 min after normalization of the blood glucose level. The global cerebral blood flow change from before hypoglycaemia to after recovery was inversely related to the initial glucose level. No change in the relative distribution of the regional cerebral blood flow ...
Recently, short-term visual deprivation has been shown to affect a variety of non-visual processes and regional cortical activity (Sathian & Zangaladze, 2001). Surprisingly, very little is known about how such visual deprivation impacts regional cerebral blood flow velocity (CBFv) or its adaptation with the underlying neuronal activity (i.e., neurovascular coupling). The current study sought to investigate the effects of short-term (two-hour) visual deprivation on regional CBFv and neurovascular coupling. CBFv (transcranial Doppler ultrasound) was measured concurrently in the posterior cerebral artery (PCA) and the middle cerebral artery (MCA). Neurovascular coupling was assessed using established methods, consisting of two minutes of baseline (eyes closed and reading), five cycles of 40 seconds reading - 20 seconds eyes-closed (primary protocol), and five cycles of 40 seconds eyes-moving - 20 seconds eyes-closed (secondary protocol). Neurovascular coupling, using both protocols, was collected ...
TY - JOUR. T1 - Lack of effect of antenatal indomethacin on fetal cerebral blood flow. AU - Parilla, B. V.. AU - Tamura, R. K.. AU - Cohen, L. S.. AU - Clark, E.. AU - Hess, L. W.. AU - Rightmire, D. A.. AU - Saade, G.. PY - 1997/1/1. Y1 - 1997/1/1. N2 - OBJECTIVE: Our purpose was to investigate fetal cerebral blood flow and the incidence of intraventricular hemorrhage in patients undergoing tocolysis with either indomethacin or magnesium sulfate at ,30 weeks gestation. STUDY DESIGN: Consenting patients at ,30 weeks gestation with preterm labor were randomized to receive indomethacin or magnesium sulfate tocolysis. Magnesium sulfate was administered intravenously with an 8 gm loading dose given over the first hour, 4 gm over the second hour, and then a maintenance infusion of 2.5 gm per hour. The infusion was continued for approximately 12 hours after the cessation of uterine contractions. Patients randomized to receive indomethacin were given an initial dose of 50 to 100 mg orally or per ...
J. M. Whitley, D. S. Prough, A. K. Lamb, D. D. Deal, D. S. DeWitt; REGIONAL CEREBRAL BLOOD FLOW FOLLOWING RESUSCITATION FROM HEMORRHAGIC SHOCK IN DOGS WITH A SUBDURAL MASS. Anesthesiology 1988;69(3A):A539. Download citation file:. ...
TY - JOUR. T1 - Effects of psychotherapy on regional cerebral blood flow during trauma imagery in patients with post-traumatic stress disorder: a randomized clinical trial. AU - Lindauer, R.J.L.. AU - Booij, J.. AU - Habraken, J.B.A.. AU - van Meijel, E.P.M.. AU - Uylings, H.B.M.. AU - Olff, M.. AU - Carlier, I.V.E.. AU - den Heeten, G.J.. AU - Eck-Smit, B.L.F.. AU - Gersons, B.P.R.. PY - 2008. Y1 - 2008. U2 - 10.1017/S0033291707001432. DO - 10.1017/S0033291707001432. M3 - Article. C2 - 17803835. VL - 38. SP - 543. EP - 554. JO - Psychological Medicine. JF - Psychological Medicine. SN - 0033-2917. IS - 4. ER - ...
Chi, O.Z., C. Hunter, X. Liu, S.K. Chokshi and H.R. Weiss. Effects of fentanyl pretreatment on regional cerebral blood flow in focal cerebral ischemia in rats. Pharmacol. 85:153-157, 2010.. Chi, O.Z., C. Hunter, X. Liu and H.R. Weiss. The effects of isoflurane pretreatment on cerebral blood flow, capillary permeability, and oxygen consumption in focal cerebral ischemia in rats. Anesth. Analg. 110:1412-1418, 2010.. Liu, X., C. Hunter, H.R. Weiss and O.Z. Chi. Effects of blockade of ionotropic glutamate receptors on blood-brain barrier disruption in focal cerebral ischemia. Neurol. Sci. 31:699-703, 2010.. Chi, O.Z., C. Hunter, X. Liu, Y. Chi and H.R. Weiss. Effects of GABAA receptor blockade on regional cerebral blood flow and blood-brain barrier disruption in focal cerebral ischemia. J. Neurol. Sci. 301:66-70, 2011.. Chi, O.Z., C. Hunter, X. Liu and H.R. Weiss. The effects of dexmedetomidine on regional cerebral blood flow and oxygen consumption during severe hemorrhagic hypotension in rats. ...
TY - JOUR. T1 - Cerebral blood flow autoregulation is impaired in schizophrenia. T2 - A pilot study. AU - Ku, Hsiao Lun. AU - Wang, Jiunn Kae. AU - Lee, Hsin-Chien. AU - Lane, Timothy Joseph. AU - Liu, I-Chao. AU - Chen, Yung Chan. AU - Lee, Yao Tung. AU - Lin, I Cheng. AU - Lin, Chia Pei. AU - Hu, Chaur-Jong. AU - Chi, Nai-Fang. PY - 2017/10. Y1 - 2017/10. N2 - Patients with schizophrenia have a higher risk of cardiovascular diseases and higher mortality from them than does the general population; however, the underlying mechanism remains unclear. Impaired cerebral autoregulation is associated with cerebrovascular diseases and their mortality. Increased or decreased cerebral blood flow in different brain regions has been reported in patients with schizophrenia, which implies impaired cerebral autoregulation. This study investigated the cerebral autoregulation in 21 patients with schizophrenia and 23 age- and sex-matched healthy controls. None of the participants had a history of cardiovascular ...
Changes in cerebral blood flow are an essential feature of Alzheimers disease and have been linked to apolipoprotein E-genotype and cerebral amyloid-deposition. These factors could be interdependent or influence cerebral blood flow via different mechanisms. We examined apolipoprotein E-genotype, amyloid beta-deposition, and cerebral blood flow in amnestic mild cognitive impairment using pseudo-continuous arterial spin labeling MRI in 27 cognitively normal elderly and 16 amnestic mild cognitive impairment participants. Subjects underwent Pittsburgh Compound B (PiB) positron emission tomography and apolipoprotein E-genotyping. Global cerebral blood flow was lower in apolipoprotein E ɛ4-allele carriers (apolipoprotein E4+) than in apolipoprotein E4- across all subjects (including cognitively normal participants) and within the group of cognitively normal elderly. Global cerebral blood flow was lower in subjects with mild cognitive impairment compared with cognitively normal. Subjects with ...
Progressive loss of brain tissue is seen in some patients with schizophrenia and might be caused by increased levels of glutamate and resting cerebral blood flow (rCBF) alterations. Animal studies suggest that normalization of glutamate levels decreases rCBF and prevents structural changes in hippocampus. However, the relationship between glutamate and rCBF in anterior cingulate cortex (ACC) of humans has not been studied in the absence of antipsychotics and illness chronicity. Ketamine is a non-competitive N-Methyl-D-Aspartate receptor antagonist that transiently induces schizophrenia-like symptoms and neurobiological disturbances in healthy volunteers (HV). Here, we used S-ketamine challenge to assess if glutamate levels were associated with rCBF in anterior cingulate cortex (ACC) in 25 male HV. Second, we explored if S-ketamine changed neural activity as reflected by rCBF alterations in thalamus and accumbens that are connected with ACC. Glutamatergic metabolites were measured in ACC with magnetic
Definition of Cerebrovascular circulation with photos and pictures, translations, sample usage, and additional links for more information.
This study sought to determine the degree of agreement between asymmetries of neuropsychological functioning and nine methods of quantifying asymmetries of regional cerebral blood flow.. The regional cerebral blood flow methods combined three markers of cerebral blood flow asymmetry (percent hemispheric difference, maximum percent probe-pair asymmetry, and number of probe-pair asymmetries) with three indexes of regional cerebral blood flow (fast compartment flow, initial slope index, and initial slope). Eleven patients with left hemispheric ischemic strokes and 13 with right hemispheric ischemic strokes were studied with the xenon-133 inhalation technique and neuropsychological tests.. Blind clinical judgments of neuropsychological asymmetry significantly correlated with all nine methods of cerebral blood flow asymmetry determination; correlations ranged from -0.42 to -0.77. Clinical judgment of asymmetry of neuropsychological functioning accurately predicted the hemisphere of lower flow in ...
TY - JOUR. T1 - Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia. T2 - A positron emission tomography study. AU - Ragland, John D. AU - Gur, Ruben C.. AU - Glahn, David C.. AU - Censits, David M.. AU - Smith, Robin J.. AU - Lazarev, Mark G.. AU - Alavi, Abass. AU - Gur, Raquel E.. PY - 1998/7. Y1 - 1998/7. N2 - Schizophrenia affects prefrontal and temporal-limbic networks. These regions were examined by contrasting regional cerebral blood flow (rCBF) during executive (Wisconsin Card Sorting Test [WCST]), and declarative memory tasks (Paired Associate Recognition Test [PART]). The tasks, and a resting baseline, were administered to 15 patients with schizophrenia and 15 healthy controls during 10 min positron emission tomography 15O-water measures of rCBF. Patients were worse on both tasks. Controls activated inferior frontal, occipitotemporal, and temporal pole regions for both tasks. Similar results were obtained for controls matched to ...
Hypoxia increases cerebral blood flow (CBF), but it is unknown whether this increase is uniform across all brain regions. We used H215O positron emission tomography imaging to measure absolute blood flow in 50 regions of interest across the human brain (n = 5) during normoxia and moderate hypoxia. PCO2 was kept constant (44 Torr) throughout the study to avoid decreases in CBF associated with the hypocapnia that normally occurs with hypoxia. Breathing was controlled by mechanical ventilation. During hypoxia (inspired PO2 = 70 Torr), mean end-tidal PO2 fell to 45 ᠶ.3 Torr (means ᠓D). Mean global CBF increased from normoxic levels of 0.39 ᠰ.13 to 0.45 ᠰ.13 ml/g during hypoxia. Increases in regional CBF were not uniform and ranged from 9.9 ᠸ.6% in the occipital lobe to 28.9 ᠱ0.3% in the nucleus accumbens. Regions of interest that were better perfused during normoxia generally showed a greater regional CBF response. Phylogenetically older regions of the brain tended to show larger ...
TY - JOUR. T1 - Different cerebral hemodynamic responses between sexes and various vessels in orthostatic stress tests. AU - Wang, Yuh Jen. AU - Chao, A. Ching. AU - Chung, Chih Ping. AU - Huang, Ying Ju. AU - Hu, Han Hwa. PY - 2010/9/1. Y1 - 2010/9/1. N2 - Objective: The argument about why the head-up tilt table test (HUT) does not include the posterior cerebral circulation, which is mainly responsible for syncope, as a monitor target has not been resolved. It is also unclear whether there is a sex difference in cerebral blood flow (CBF) changes. We hypothesized that orthostatic CBF changes more in the posterior circulation than in the anterior circulation and is different between sexes. Methods: Thirty healthy volunteers (13 female and 17 male) were recruited for the HUT. The blood pressure (BP), middle cerebral artery flow velocity (MCAFV), and posterior cerebral artery flow velocity (PCAFV) were monitored simultaneously. Static cerebral autoregulation (CA) was calculated. Results: The female ...
Although it is now well documented (6, 8) that pial as well as intracerebral vessels are amply supplied with sympathetic adrenergic nerves which, as shown for pial arteries, fulfill ultra-structural...
Four major, interdependent mechanisms are involved in the control of cerebral blood flow: metabolic coupling: neural control, involving both extrinsic and intrinsic neural pathways: Pco2 and autoregulation. Although this division may be somewhat artificial and these control mechanisms probably operate in concert, it is useful to consider each separately. Metabolic Control Local cerebral blood flow (CBF) is regionally heterogeneous. The varied pattern of CBF is neither random nor related to the anatomic organization of the cerebral vasculature or to known differences in the innervation patterns of the cerebral vessels. Neuronal activity is the principal energy-consuming process in the brain. Local cerebral blood flow adjusts to the level of energy generation; therefore, it is the activity in the neuronal circuits that is the major determinant of variations and regional patterns of cerebral blood flow. Normally there is exquisite coupling between the regional cerebral metabolic demand for oxygen ...
Oak Za Chi, Hwu Meei Wei, Dorene A. OHara, Arabinda K. Sinha, Harvey R. Weiss; Effects of Pentobarbital and Isoflurane on Regional Cerebral Oxygen Extraction and Consumption with Middle Cerebral Artery Occlusion in Rats. Anesthesiology 1993;79(2):299-305. Download citation file:. ...
Background and aims: Aging brain has been demonstrated to be the main risk factor for dementia and Alzheimers disease (AD). Recent findings provide clear evidence that the structural and functional integrity of the brain depends on the delicate balance between substrate delivery through blood flow and energy demands imposed by neural activity. Imaging studies of aging have in general shown reductions of cerebral blood flow (CBF) and the cerebral metabolic rates of oxygen (CMRO2) in healthy elderly adults. Based on the existing evidence, we hypothesized the CBF and CMRO2 in healthy young subjects will be higher than CBF and CMRO2 in elderly adults which itself should be higher than AD patients. Therefore, we designed the present studies specifically to reveal the role of defective cerebral oxygen metabolism and cerebral blood flow in normal aging. ...
This study investigated whether the nitric oxide synthase inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) would alter blood flow and oxygen balance in the ischemic cerebrocortex of isoflurane-anesthetized Long-Evans rats.. Fifteen minutes after middle cerebral artery occlusion, L-NAME (1.5 mg/min per kilogram) was infused intravenously to the L-NAME group (n = 14), and normal saline was given to the control group (n = 14) for 45 minutes. In each group, regional cerebral blood flow was determined with [14C]iodoantipyrine, and arterial and venous oxygen saturations were determined by microspectrophotometry.. In both groups regional cerebral blood flow of the ischemic cortex was significantly lower than that of the contralateral cortex ([mean +/- SD] 55 +/- 13 versus 110 +/- 29 mL/min per 100 g in the control group and 35 +/- 13 versus 90 +/- 24 mL/min per 100 g in the L-NAME group). Compared with the blood flow in the ischemic cortex of the control group, L-NAME significantly reduced ischemic ...
The results of studies utilizing the nitrous oxide technic for measuring cerebral blood flow have been reviewed and divided into three groups: (1) those in which cerebral blood flow and metabolism were normal, (2) those in which cerebral blood flow was increased, and (3) those in which cerebral blood flow and metabolism were decreased. The factors which apparently regulate and control cerebral blood flow and metabolism are reviewed and discussed.. ...
3) with the assumption that the large and small vessel Hcts are equal.12. Strictly, recirculation effects should be recognized and removed from the curves. In reality, unless there is significant BBB permeability or areas of very low flow, recirculation effects may be ignored and actually lead to improved estimates of plasma volume that are less sensitive to contrast agent delivery rates (ie, CBF). In low-flow regions, if the tracer does not complete its first passage within the time given for the measurement (usually about 25-30 seconds), it will be undercounted and vp will be underestimated. Because of this result, some authors writing about ischemia have used the term perfused CBV.13 This may account for the discrepancies seen in between PWI and C15O PET estimates of CBV in ischemia.14 In fact, in the extreme, one would prefer to image as late after injection as possible; when the contrast agent concentration is changing slowly, it more closely approximates a steady-state or blood pool ...
The Windkessel properties of the vasculature are known to play a significant role in buffering arterial pulsations, but their potential importance in dampening low-frequency fluctuations in cerebral blood flow has not been clearly examined. In this study, we quantitatively assessed the contribution of arterial Windkessel (peripheral compliance and resistance) in the dynamic cerebral blood flow response to relatively large and acute changes in blood pressure. Middle cerebral artery flow velocity (MCA(V); transcranial Doppler) and arterial blood pressure were recorded from 14 healthy subjects. Low-pass-filtered pressure-flow responses (,0.15 Hz) during transient hypertension (intravenous phenylephrine) and hypotension (intravenous sodium nitroprusside) were fitted to a two-element Windkessel model. The Windkessel model was found to provide a superior goodness of fit to the MCA(V) responses during both hypertension and hypotension (R² = 0.89 ± 0.03 and 0.85 ± 0.05, respectively), with a ...
Several techniques have been proposed to estimate relative changes in cerebral metabolic rate of oxygen consumption (CMRO2) by exploiting combined BOLD fMRI and cerebral blood flow data in conjunction with hypercapnic or hyperoxic respiratory challenges. More recently, methods based on respiratory challenges that include both hypercapnia and hyperoxia have been developed to assess absolute CMRO2, an important parameter for understanding brain energetics. In this paper, we empirically optimize a previously presented original calibration model relating BOLD and blood flow signals specifically for the estimation of oxygen extraction fraction (OEF) and absolute CMRO2.To do so, we have created a set of synthetic BOLD signals using a detailed BOLD signal model to reproduce experiments incorporating hypercapnic and hyperoxic respiratory challenges at 3 T. A wide range of physiological conditions was simulated by varying input parameter values (baseline cerebral blood volume (CBV0), baseline cerebral ...
We used H(2)15O positron emission tomography (PET) to measure age-related changes in regional cerebral blood flow (rCBF) during a verbal recognition memory task. Twelve young adults (20 to 29 years) and 12 older adults (62 to 79 years) participated. Separate PET scans were conducted during Encoding, Baseline, and Retrieval conditions. Each of the conditions involved viewing a series of 64 words and making a two-choice response manually. The complete reaction time (RT) distributions in each task condition were characterized in terms of an ex-Gaussian model (convolution of exponential and Gaussian functions). Parameter estimates were obtained for the mean of the exponential component (tau), representing a task-specific decision process and the mean of the Gaussian component (mu) representing residual sensory coding and response processes. Independently of age group, both tau and mu were higher in the Encoding and Retrieval conditions than in the Baseline condition, and tau was higher during ...
All inhaled anesthetics increase cerebral blood flow and decrease cerebral metabolic rate for oxygen (CMRO2). Nitrous oxide, however, will increase CMRO2. Nitrous oxide, as well as inhaled anesthetics, causes cerebral vasodilation. However, if the patients blood pressure drops, the increase in cerebral blood flow will be attenuated or abolished because volatile anesthetics inhibit autoregulation. Isoflurane causes the least cerebral vasodilation, maintaining autoregulation better than other volatile anesthetics. Isoflurane also has no effect on cerebrospinal fluid (CSF) production and decreases resistance to CSF absorption. Desflurane increases CSF production without significantly effecting CSF reabsorption. ...
To test the hypothesis that craving for alcohol in the alcohol-dependent individual is mediated by a limbic circuit involving the caudate nuclei, regional cerebral blood flow was measured with [99mTc]HMPAO SPECT during control and craving conditions in 9 alcohol-dependent subjects. In all subjects, blood flow in the head of the right caudate nucleus increased during the craving condition, and these blood flow increases were strongly correlated with the experimentally induced increases in craving for alcohol. These new findings suggest a functional role for the limbic striatum in the mediation of craving and impaired control over alcohol consumption.
Dynamic susceptibility contrast MRI (DSC-MRI) is the current standard for the measurement of Cerebral Blood Flow (CBF) and Cerebral Blood Volume (CBV), but it is not suitable for the measurement of Extraction Flow (EF) and may not allow for absolute quantification. The objective of this study was to …
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Author(s): Moore S, Hallsworth K, Jakovljevic D, Blamire A, He J, Ford G, Rochester L, Trenell M. Publication type: Conference Proceedings (inc. Abstract). Publication status: Published. Conference Name: UK Stroke Forum 2014. Year of Conference: 2014. Pages: 32-32. Print publication date: 01/11/2014. Online publication date: 01/12/2014. ISSN: 1747-4930. Publisher: Wiley-Blackwell Publishing Asia. URL: http://dx.doi.org/10.1111/ijs.12374_12. DOI: 10.1111/ijs.12374_12. Notes: 072. Series Title: International Journal of Stroke. ...
We have previously reported focal abnormalities of regional cerebral blood flow (rCBF) in a group of 33 patients with major depression. This report, on an extended sample of 40 patients who demonstrated identical regional deficits to those previously described, examines the relationships between depressive symptoms and patterns of rCBF. Patients symptom ratings were subjected to factor analysis, producing a three-factor solution. The scores for these three factors, which corresponded to recognizable dimensions of depressive illness, were then correlated with rCBF. The first factor had high loadings for anxiety and correlated positively with rCBF in the posterior cingulate cortex and inferior parietal lobule bilaterally. The second factor had high loadings for psychomotor retardation and depressed mood and correlated negatively with rCBF in the left dorsolateral prefrontal cortex and left angular gyrus. The third factor had a high loading for cognitive performance and correlated positi
The aim of the study is to determine if regional cerebral blood flow, measured by dynamic arterial spin labeling (dASL), can be a biomarker for stage of Alzheimers disease. The study is designed to be conducted in 2 parts in participants with mild to moderate Alzheimers disease, and participants with normal cognition. Various imaging studies will be done using magnetic resonance imaging (MRI) and positron emission tomography (PET) along with neurocognitive assessments. Participants who meet the study-entry criteria will have up to 8 study visits. Repeat imaging studies may be required if the initial data are incomplete or un-interpretable. The maximum number of PET scans during the study will be limited to four ...
The aim of the study is to determine if regional cerebral blood flow, measured by dynamic arterial spin labeling (dASL), can be a biomarker for stage of Alzheimers disease. The study is designed to be conducted in 2 parts in participants with mild to moderate Alzheimers disease, and participants with normal cognition. Various imaging studies will be done using magnetic resonance imaging (MRI) and positron emission tomography (PET) along with neurocognitive assessments. Participants who meet the study-entry criteria will have up to 8 study visits. Repeat imaging studies may be required if the initial data are incomplete or un-interpretable. The maximum number of PET scans during the study will be limited to four ...
Modulation of the cholinergic neurotransmitter system results in changes in memory performance, including working memory (WM), in animals and in patients with Alzheimer disease. To identify associated changes in the functional brain response, we studied performance measures and regional cerebral blood flow (rCBF) using positron emission tomography (PET) in healthy subjects during performance of a WM task. Eight control subjects received an infusion of saline throughout the study and 13 experimental subjects received a saline infusion for the first 2 scans followed by a continuous infusion of physostigmine, an acetylcholinesterase inhibitor, for the subsequent 8 scans. rCBF was measured using H215O and PET in a sequence of 10 PET scans that alternated between rest and task scans. During task scans, subjects performed the WM task for faces. Physostigmine both improved WM efficiency, as indicated by faster reaction times, and reduced WM task-related activity in anterior and posterior regions of ...
Though genetic and environmental determinants of systemic haemodynamic have been reported, surprisingly little is known about their influences on cerebral haemodynamics. We assessed the potential geographical effect on cerebral haemodynamics by comparing the individual differences in cerebral blood flow velocity (CBFv), vasomotor tone (critical closing pressure- CrCP), vascular bed resistance (resistance-area product- RAP) and cerebral autoregulation (CA) mechanism on healthy subjects and acute ischaemic stroke (AIS) patients from two countries. Participants were pooled from databases in Leicester, United Kingdom (LEI) and São Paulo, Brazil (SP) research centres. Stroke patients admitted within 48 h of ischaemic stroke onset, as well as age- and sex-matched controls were enrolled. Beat-to-beat blood pressure (BP) and bilateral mean CBFv were recorded during 5 min baseline. CrCP and RAP were calculated. CA was quantified using transfer function analysis (TFA) of spontaneous oscillations in arterial BP
Though genetic and environmental determinants of systemic haemodynamic have been reported, surprisingly little is known about their influences on cerebral haemodynamics. We assessed the potential geographical effect on cerebral haemodynamics by comparing the individual differences in cerebral blood flow velocity (CBFv), vasomotor tone (critical closing pressure- CrCP), vascular bed resistance (resistance-area product- RAP) and cerebral autoregulation (CA) mechanism on healthy subjects and acute ischaemic stroke (AIS) patients from two countries. Participants were pooled from databases in Leicester, United Kingdom (LEI) and São Paulo, Brazil (SP) research centres. Stroke patients admitted within 48 h of ischaemic stroke onset, as well as age- and sex-matched controls were enrolled. Beat-to-beat blood pressure (BP) and bilateral mean CBFv were recorded during 5 min baseline. CrCP and RAP were calculated. CA was quantified using transfer function analysis (TFA) of spontaneous oscillations in arterial BP
The goal of this study was to determine if regional cerebral blood flow (rCBF)in the left and right hemithalami or the left and right heads of the cau
TY - JOUR. T1 - Opioids and the prostanoid system in the control of cerebral blood flow in hypotensive piglets. AU - Armstead, W. M.. AU - Mirro, R.. AU - Busija, D. W.. AU - Leffler, Charles. PY - 1991/1/1. Y1 - 1991/1/1. N2 - The interaction between opioid and prostanoid mechanisms in the control of cerebral hemodynamics was investigated in the conscious hypotensive piglet. Radiomicrospheres were used to determine regional cerebral blood flow (rCBF) in piglets pretreated with the opioid receptor antagonist, naloxone, or its vehicle, saline, during normotension, hypotension, and after the administration of indomethacin, a cyclooxygenase inhibitor, during hypotension. Hemorrhage (30 ml/kg) decreased systemic arterial pressure from 68 ± 12 to 40 ± 10 mm Hg but did not decrease blood flow to any brain region. Indomethacin treatment (5 mg/kg) of hypotensive piglets decreased blood flow to all brain regions within 20 min; this decrease blood flow to all brain regions within 20 rebral vascular ...
Continuous recording of mean cerebral blood flow velocity (MCBFV) by Doppler ultrasound allows detection of low-frequency (LF) oscillations, which reflect sympathetic activity in the cerebral circulation. To establish whether the sympathetic drive to the cerebral circulation is altered in patients with compensated cirrhosis, and, if so, where alterations take place, LF oscillations of MCBFV, heart rate (RR interval) and systolic arterial pressure (SAP) were analysed in 10 patients with cirrhosis and 10 control subjects during supine rest and on stimulation of carotid baroreceptors using a neck chamber applying sinusoidal suction. Bivariate analysis was used to study the relationship between pairs of oscillations. In the case of a significant association, the delay in the appearance of the oscillation in MCBFV, SAP and RR was calculated. Baroreceptor stimulation induced significant increases in SAP LF and RR LF power in both groups, while MCBFV LF power increased only in controls. During ...
TY - JOUR. T1 - White matter lesions after occlusion of the bilateral carotid arteries in the rat -temporal profile of cerebral blood flow (CBF), oligodendroglia and myelin. AU - Tomimoto, Hidekazu. AU - Akiguchi, Ichiro. AU - Wakita, Hideaki. AU - Kimura, Jun. PY - 1997/12/1. Y1 - 1997/12/1. N2 - In the present investigation, we examined cerebral blood flow (CBF), numerical density of oligodendroRlia and extent of white matter lesions after bilateral libation of common carotid arteries in Wistar rats, Doppler flow meter re\ealed a reduction of CBF to 30-40, of that before operation after 1 and 3 days, however recovered to ,10 60 ‰, after 7 and 14 days, Semiquantitative evaluation with immuohistochemistry for transferrin showed a numerical decrease of oligodendroglia in the medial corpus callosum after 14 and !i() clays, Tissue rarefaction promptly occurred in the optic nerve and optic tract after ,, days, whereas it was- delayed to 7 clays after operation and increased in intensity ...
In the article, cerebral perfusion pressure, or CPP, is the net pressure gradient which affects cerebral blood flow to the brain, known as brain perfusion.
Standard techniques of cerebral blood flow (CBF) measurement provide information on both global and regional flow in patients with cerebral ischaemia or infarction. Recent availability of positron emission tomography (PET), recording oxygen and glucose metabolism, as well as blood flow and blood volume, gives a more detailed and accurate understanding of pathophysiological changes after stroke.. Changes in cerebral infarction. NON-ISCHAEMIC HEMISPHERE. Mild reduction in global CBF - perhaps due to transneuronal depression of metabolism in the unaffected hemisphere - diaschisis.. In the normal brain, cerebral blood flow to a particular part varies depending on the metabolic requirements, i.e. the supply of 02 and glucose is coupled to the tissue needs. After infarction, between areas of reduced flow and areas of luxury perfusion, lie areas of relative luxury perfusion where reduced flow exceeds the tissue requirements, i.e. uncoupling of flow and metabolism has occurred.. Studies with SPECT ...
The effects of positioning of head of bed positioning on blood flow reaching the brain can now be monitored non-invasively and continuously using a new device designed by University of Pennsylvania.
This study was performed to investigate the regulatory mechanism of cerebral blood flow of adenosine A $_{2B}$ receptor agonist in the rats, and to define whether its mechanism is mediated by adenylate cyclase, guanylate cyclase and potassium channel. In pentobarbital-anesthetized, pancuronium-par...
Mounting evidence indicates that regular engagement in aerobic exercise improves executive functioning and cerebrovascular health in older adulthood. Recent evidence also points toward some similar benefits in young adults, despite presumed optimal brain health in that population. The present study sought to clarify which specific cognitive functions are linked to regular exercise in young adults (18-30 years), and to gain insight into the possible mechanisms underlying such links. To this end, the current study examined performance on a wide variety of executive function tasks in relation to aerobic fitness, self-reported habitual physical activity, and cerebrovascular health (as measured by resting cerebral blood flow, which was indexed by blood flow velocity through the middle cerebral artery; and cerebrovascular reactivity to carbon dioxide - the most potent regulatory stimulus of the cerebrovasculature). Multiple regression analyses revealed that more frequent physical activity, but not ...
Cerebral blood flow and metabolism have been evaluated during exercise to elicit robust activation compared with during anaesthesia. It is demonstrated that physical exercise requires an approximately 20 % increase in cerebral blood flow and metabolic rate for oxygen. This reflects that low intensity exercise is associated with increasing cerebral oxygenation, while cerebral oxygenation decreases during maximal exercise, since marked hyperventilation reduces arterial carbon dioxide tension and therefore cerebral blood flow at the same time as the metabolic rate for oxygen is elevated ...
Type 2 diabetes exerts complex effects on cerebral microvasculature that may alter cerebral blood flow regulation. We found a decrease of mean BFV and an increase of CVR in type 2 diabetic patients during baseline, hypocapnia, and hypercapnia. Baseline mean BFV was negatively associated with periventricular WMH grade and volume on T2-weighted images and with A1C and inflammation markers. WMHs were also linked with uncontrolled diabetes, elevated CVR, and impaired CO2 reactivity. The relationship between WMH, uncontrolled diabetes and reduced BFV is of clinical relevance as a potential mechanism for cerebrovascular disease in elderly with type 2 diabetes.. Aging is associated with brain atrophy, changes in frontal subcortical white matter, and executive cognitive dysfunction (9). The CO2 reactivity diminishes with age, uncontrolled diabetes, and risk factors for atherosclerosis (22). In community-living elderly people, blood flow in the WMHs was lower compared with normal-appearing white matter ...
article{a42a0f99-94fd-4913-b3c1-936a0a2ea31b, abstract = {Regional cerebral blood flow (rCBF) was studied in patients with Alzheimers disease (AD) before and after 14 months of tacrine treatment. The treated group was compared with an identical reference group of untreated AD patients. At baseline the two groups showed an identical rCBF and mean hemispheric blood flow. After 14 months the tacrine-treated patients showed a stable rCBF level and a significant increase in rCBF in the central-parietal regions, compared to the untreated reference group, who showed typical AD reductions in rCBF in these regions. Clinical outcome: 7 of 9 patients in the tacrine group were clinically unchanged or slightly improved during the study time. In the untreated group 8 of 11 patients had deteriorated in clinical assessments and none had improved. Long-term tacrine treatment in Alzheimers disease may delay the progression of symptoms.}, author = {Minthon, Lennart and Nilsson, Karin and Edvinsson, Lars and ...
TY - JOUR. T1 - Phenylephrine increases cerebral blood flow during low-flow hypothermic cardiopulmonary bypass in baboons. AU - Schwariz, Arthur E.. AU - Minanov, Oktavijan. AU - Stone, J. Gilbert. AU - Adams, David C.. AU - Sandhu, Aqeel A.. AU - Pearson, Mark E.. AU - Kwiatkowski, Pawel. AU - Young, William L.. AU - Michler, Robert E.. PY - 1996/8/23. Y1 - 1996/8/23. N2 - Background: Although low-flow cardiopulmonary bypass (CPB) has become a preferred technique for the surgical repair of complex cardiac lesions in children, the relative hypotension and decrease in cerebral blood flow (CBF) associated with low flow may contribute to the occurrence of postoperative neurologic injury. Therefore, it was determined whether phenylephrine administered to increase arterial blood pressure during low-flow CPB increases CBF. Methods: Cardiopulmonary bypass was initiated in seven baboons during fentanyl, midazolam, and isoflurane anesthesia. Animals were cooled at a pump flow rate of 2.5 1 · min -1 · m ...
TY - JOUR. T1 - Cognitive function and dynamic cerebral blood flow regulation in multiple concussions. AU - Kumazaki, Akira. AU - Ogoh, Shigehiko. AU - Hirasawa, Ai. AU - Sakai, Sadayoshi. AU - Hirose, Norikazu. PY - 2018/3. Y1 - 2018/3. N2 - Background: Concussion causes acute, short-term brain dysfunctions. However, the impact of repetitive concussion history on brain function remains unclear. Objectives: The present study examined the effect of a history of multiple concussions on the cognitive functions and dynamic cerebral blood flow (CBF) regulation in collegiate rugby football players. Methods: Nine male rugby football players with a history of≤1 concussion and nine players with a history of multiple concussions (≤ 4 concussions) participated in this study. Reaction time and working memory were assessed using a neurocognitive assessment device (CogSport; CogState Ltd., Melbourne, Australia). Arterial blood pressure and middle cerebral artery blood velocity (MCAv) were measured ...
This study was performed to determine whether stimulation of the carotid chemoreceptors increases total or regional cerebral blood flow and whether activation of arterial chemoreceptors contributes to cerebral vasodilation during systemic hypoxemia. In anesthetized and ventilated dogs, carotid chemoreceptors were stimulated with nicotine or hypoxic and hypercapnic blood. To measure total and regional cerebral blood flow, we used labeled 15-mu microspheres. Stimulation of chemoreceptors did not increase cerebral blood flow or produce significant redistribution of cerebral blood flow, even though the chemoreflex was intact in these animals (as manifested by vasoconstriction in muscle, kidney, and small bowel) and the cerebral vessels dilated in response to systemic hypercapnia. In other studies in anesthetized, ventilated dogs and rhesus monkeys, cerebral vasodilator responses to systemic hypoxemia were observed before and after denervation of carotid and aortic chemoreceptors. Systemic hypoxemia ...
Patients with Alzheimer disease (AD) had reduced regional cerebral blood flow (rCBF) in the posterior parietotemporal region compared with controls, as determined with technetium-99m hexamethyl propyleneamine oxime and single photon emission tomography. Central cholinergic stimulation with physostigmine produced a focal increase in rCBF in the posterior parietotemporal region in the patients with AD but not in controls.
TY - JOUR. T1 - Low Cerebral Oxygen Consumption and Blood Flow in Patients With Cirrhosis and an Acute Episode of Hepatic Encephalopathy. AU - Iversen, Peter. AU - Sørensen, Michael. AU - Bak, Lasse Kristoffer. AU - Waagepetersen, Helle Sønderby. AU - Vafaee, Manouchehr Seyedi. AU - Borghammer, Per. AU - Mouridsen, Kim. AU - Jensen, Svend Borup. AU - Vilstrup, Hendrik. AU - Schousboe, Arne. AU - Ott, Peter. AU - Gjedde, Albert. AU - Keiding, Susanne. PY - 2009/3. Y1 - 2009/3. N2 - Background & Aims: It is unclear whether patients with hepatic encephalopathy (HE) have disturbed brain oxygen metabolism and blood flow. Methods: We measured cerebral oxygen metabolism rate (CMRO2) by using 15O-oxygen positron emission tomography (PET); and cerebral blood flow (CBF) by using 15O-water PET in 6 patients with liver cirrhosis and an acute episode of overt HE, 6 cirrhotic patients without HE, and 7 healthy subjects. Results: Neither whole-brain CMRO2 nor CBF differed significantly between cirrhotic ...
BACKGROUND AND PURPOSE: Blood vessels are usually conspicuous on dynamic CT perfusion images. The presence of large vessels may lead to overestimation of the quantitative value of cerebral blood flow (CBF). We evaluated the efficacy of the vascular-pixel elimination (VPE) method in quantitative CT perfusion imaging, in comparison with positron emission tomography (PET).. METHODS: Five healthy volunteers underwent CT perfusion and PET studies. A four-channel multi-detector row CT scanner was used. Dynamic cine scanning was performed after bolus injection of an intravenous contrast agent. CT-CBF was calculated by the central volume principle and deconvolution method. PET was performed after infusion of 15O-labeled water. PET-CBF was calculated by using a nonlinear least squares method. Average CBF values of the whole section, gray matter, and white matter with both CT and PET were compared after image registration. The comparison was performed with and without VPE. In the VPE method, the vascular ...
Hyperventilation is frequently used to prevent or postpone the development of cerebral edema and intracranial hypertension in patients with fulminant hepatic failure (FHF). The influence of such therapy on regional cerebral blood flow (rCBF) remains, however, unknown. In this study the CBF-distribution pattern was determined within the first 12 hours after development of hepatic encephalopathy (HE) stage 4 before and during hyperventilation. Ten consecutive patients (median age 48 [range 33-57] years) with FHF and 9 healthy controls (median age 54 [24-58] years) had rCBF determined by single photon emission computed tomography (SPECT) using intravenous injection of 133Xenon. For determination of high resolution CBF pattern, the patients were also studied with 99mTc-hexa-methylpropyleneamine oxime (HMPAO) in the hyperventilation condition. There was no significant difference in the rCBF distribution pattern during normoventilation as compared with hyperventilation. The anterior to posterior (AP) ...
The distribution of regional cerebral blood flow (rCBF) was examined in conscious, voluntarily diving rats using the brain blood flow tracer N-[14C]isopropyl-p-iodoamphetamine and quantitative autoradiography. A detailed examination of the regional distribution of cerebral blood flow revealed that almost all brain regions were hyperperfused during diving. During diving, rCBF increased by an average of 1.7-fold in 29 of the 33 brain regions examined, despite a 69.2 % decrease in cardiac output. Only some regions of the basal ganglia (caudate-putamen and globus pallidus) and limbic areas (hippocampus and amygdala) did not increase rCBF significantly during diving. We determined that the increase in rCBF during diving is primarily due to a corresponding 20.9 % decrease in cerebrovascular resistance. A significant increase in perfusion pressure during diving also potentially contributed to the increase in rCBF. Because some brain regions did not increase flow significantly during diving, these ...
The first five chapters of the thesis review the literature on intracranial pressure, the cerebral circulation and their interrelation and set the scene for the experimental work which is described in chapters 6 to 11. Intracranial pressure is now measured routinely in many clinical centres but a great deal of caution is required in interpreting the results, particularly with respect to the method of measurement, the history of any raised pressure and the values of other physiological variables such as blood pressure and cerebral blood flow. The cerebral circulation itself displays a remarkable tendency to remain constant, the fundamental concept being that there exists a basic control mechanism which acts to maintain cerebral blood flow in order to meet the metabolic requirements of the brain. The methods used to measure cerebral blood flow in the work described are metabolically inert gas clearance techniques based on the Pick principle. Hemisphere blood flow in baboons was measured by the ...
Measurements of regional cerebral blood flow (rCBF), analysis ofcerebrospinal fluid, auditory brain stem responses (ABR) andoculomotor tests
BACKGROUND AND PURPOSE: Perfusion-weighted imaging is used to select patients with acute ischemic stroke for intervention, but knowledge of cerebral perfusion can also inform the understanding of ischemic injury. Arterial spin labeling allows repeated measurement of absolute cerebral blood flow (CBF) without the need for exogenous contrast. The aim of this study was to explore the relationship between dynamic CBF and tissue outcome in the month after stroke onset. METHODS: Patients with nonlacunar ischemic stroke underwent ≤5 repeated magnetic resonance imaging scans at presentation, 2 hours, 1 day, 1 week, and 1 month. Imaging included vessel-encoded pseudocontinuous arterial spin labeling using multiple postlabeling delays to quantify CBF in gray matter regions of interest. Receiver-operator characteristic curves were used to predict tissue outcome using CBF. Repeatability was assessed in 6 healthy volunteers and compared with contralateral regions of patients. Diffusion-weighted and T2-weighted
Clinical studies consistently report structural impairments (i.e.: ventricular enlargement, decreased volume of anterior cingulate cortex or hippocampus) and functional abnormalities including changes in regional cerebral blood flow in individuals suffering from schizophrenia, which can be evaluated by magnetic resonance imaging (MRI) techniques. The aim of this study was to assess cerebral blood perfusion in several schizophrenia-related brain regions using Arterial Spin Labelling MRI (ASL MRI, 9.4 T Bruker BioSpec 94/30USR scanner) in rats. In this study, prenatal exposure to methylazoxymethanol acetate (MAM, 22 mg/kg) at gestational day (GD) 17 and the perinatal treatment with Delta-9-tetrahydrocannabinol (THC, 5 mg/kg) from GD15 to postnatal day 9 elicited behavioral deficits consistent with schizophrenia-like phenotype, which is in agreement with the neurodevelopmental hypothesis of schizophrenia. In MAM exposed rats a significant enlargement of lateral ventricles and perfusion changes ...
Maintaining a constant cerebral blood flow during a change in cerebral perfusion pressure is known as autoregulation. The integrity of this phenomenon is considered to be important in preventing cerebral lesions in preterm infants. A study was carried out using Doppler ultrasound measurements of cerebral blood flow velocities (CBFV) as an indicator of alterations in cerebral haemodynamics. CBFV were recorded on a beat to beat basis over 60 second epochs, during which time the cerebral perfusion pressure was changed by rapidly altering the infants posture from horizontal to either 20 degrees head up or head down. An informative response in CBFV was considered to be either (a) a uniphasic, immediate, passive alteration in velocity occurring with the change in posture and without a subsequent change or (b) a biphasic response of an initial change in CBFV followed within 20 seconds by a second response. This latter response is considered to be consistent with autoregulatory activity. A total of 501 ...
TY - JOUR. T1 - Effect of amphetamine on cerebral blood flow and capillary perfusion. AU - Russo, Karen E.. AU - Hall, Wyatt. AU - Chi, Oak Z.. AU - Sinha, Arabinda K.. AU - Weiss, Harvey R.. PY - 1991/2/22. Y1 - 1991/2/22. N2 - The purpose of this study was to determine the cerebral regional microvascular and vascular responses to amphetamine sulfate at a dose (5 mg/kg) known to affect neuronal function. Cerebral blood flow (14C-iodoantipyrine method) and percent of perfused capillaries (fluorescein isothiocyanate-dextran and alkaline phosphatase staining method) were determined during control and after intravenous administration of amphetamine in conscious Long-Evans rats. Amphetamine caused an increase in blood pressure (34%) and heart rate (31%). There was a significant increase in averaged cerebral blood flow from 98 ±8to 166±9 ml/min/100 g after amphetamine. This flow increase was significant in the cortex, basal ganglia, pons and medulla, however the increase was not significant in the ...
TY - JOUR. T1 - Comparison of glucose metabolism and cerebral blood flow during cortical motor activation. AU - Hallett, M.. AU - Zeffiro, T.. AU - Dubinsky, R. M.. AU - Bierner, S. M.. N1 - Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 1994. Y1 - 1994. N2 - Regions of cerebral cortex activated in normal subjects making simple, repetitive, voluntary wrist movements were studied with positron emission tomography (PET). The regional cerebral metabolic rate of glucose utilization was studied with 2 [18F]fluoro-2-deoxy-D-glucose (FDG), and regional cerebral blood flow was studied with 15O-labeled water. No significant activation was found with the cerebral metabolic rate studies. Studies of regional cerebral blood flow showed significant activation of the contralateral sensorimotor cortex region of 42%, of the ipsilateral sensorimotor cortex region of 19%, and of the medial frontal cortex of 30% compared with the resting state. Increases in blood flow in the contralateral ...
Laser Doppler flowmetry (LDF) is a method by which relative cerebral blood flow (CBF) of the cortex can be measured. Although the method is easy to employ, LDF only measures relative CBF, while absolute CBF cannot be quantified. LDF is useful for investigating CBF changes in a number of different applications including neurovascular and stroke research. This chapter will prepare the reader for rodent experiments using LDF with two preparations. The closed skull preparation can be used to monitor CBF with an intact skull, but in adult rats, thinning of the skull is required to obtain an accurate cortical CBF signal. The open skull preparation requires a craniotomy to expose the surface of the brain and the LDF probe is held close to the surface to measure cerebral perfusion. © 2014 Springer Science+Business Media New York.
Laser Doppler flowmetry (LDF) is a method by which relative cerebral blood flow (CBF) of the cortex can be measured. Although the method is easy to employ, LDF only measures relative CBF, while absolute CBF cannot be quantified. LDF is useful for investigating CBF changes in a number of different applications including neurovascular and stroke research. This chapter will prepare the reader for rodent experiments using LDF with two preparations. The closed skull preparation can be used to monitor CBF with an intact skull, but in adult rats, thinning of the skull is required to obtain an accurate cortical CBF signal. The open skull preparation requires a craniotomy to expose the surface of the brain and the LDF probe is held close to the surface to measure cerebral perfusion.
1. The effects of insulin hypoglycaemia on cerebral blood flow and metabolism have been examined in unanaesthetized, unrestrained calves between 1 and 26 days after birth. 2. Cerebral blood flow was measured with an inert gas technique using molecular hydrogen, and cerebral metabolism was quantified by determination of arterio-cerebral venous (A--V) concentration differences for oxygen, glucose, lactate, pyruvate, acetoacetate, beta-D-hydroxybutyrate and ammonia. 3. During normoglycaemia the mean (A--V) difference for glucose was close to one sixth that of oxygen, on a molar basis. A small net loss of pyruvate from the brain was found, but there was no significant (A--V) difference for lactate. Arterial concentrations of acetoacetate and beta-D-hydroxybutyrate were low, and no utilization of ketone bodies by the brain was demonstrated. 4. Moderate hypoglycaemia (arterial plasma glucose concentration 1--2 m-mole/l.) had no measurable effect on either cerebral blood flow or metabolism. 5. During ...
TY - GEN. T1 - Cerebral hemodynamic changes after wartime traumatic brain injury. AU - Razumovsky, Alexander. AU - Tigno, Teodoro. AU - Hochheimer, Sven M.. AU - Stephens, Fred L.. AU - Bell, Randy. AU - Vo, Alexander H.. AU - Severson, Meryl A.. AU - Marshall, Scott A.. AU - Oppenheimer, Stephen M.. AU - Ecker, Robert. AU - Armonda, Rocco A.. PY - 2013. Y1 - 2013. N2 - Traumatic brain injury (TBI) is associated with the severest casualties from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). From October 1, 2008, the U.S. Army Medical Department initiated a transcranial Doppler (TCD) ultrasound service for TBI; included patients were retrospectively evaluated for TCD-determined incidence of post-traumatic cerebral vasospasm and intracranial hypertension after wartime TBI. Ninety patients were investigated with daily TCD studies and a comprehensive TCD protocol, and published diagnostic criteria for vasospasm and increased intracranial pressure (ICP) were applied. TCD signs ...
TY - JOUR. T1 - Validation of the CBF, CBV, and MTT Values by Perfusion MRI in Chronic Occlusive Cerebrovascular Disease. T2 - A Comparison with 15O-PET. AU - Kaneko, Koichiro. AU - Kuwabara, Yasuo. AU - Mihara, Futoshi. AU - Yoshiura, Takashi. AU - Nakagawa, Makoto. AU - Tanaka, Atsuo. AU - Sasaki, Masayuki. AU - Koga, Hirofumi. AU - Hayashi, Kazutaka. AU - Honda, Hiroshi. PY - 2004/5. Y1 - 2004/5. N2 - Rationale and Objectives. To evaluate the reliability of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) values obtained by deconvolution algorithm perfusion-weighted MR imaging (D-PWI), we compared these values with those obtained by first-moment algorithm perfusion-weighted MR imaging (F-PWI) and 15O-PET. Subjects and Methods. Six healthy volunteers and eleven patients with chronic occlusive cerebrovascular disease were studied with both perfusion-weighted MR imaging and 15O-PET, and region-of-interest analyses were performed. Normalization factors for CBF ...
OBJECT Current clinical neuromonitoring techniques lack adequate surveillance of cerebral perfusion. In this article, a novel thermal diffusion (TD) microprobe is evaluated for the continuous and quantitative assessment of intraparenchymal regional cerebral blood flow (rCBF). METHODS To characterize the temporal resolution of this new technique, rCBF measured using the TD microprobe (TD-rCBF) was compared with rCBF levels measured by laser Doppler (LD) flowmetry during standardized variations of CBF in a sheep model. For validation of absolute values, the microprobe was implanted subcortically (20 mm below the level of dura) into 16 brain-injured patients, and TD-rCBF was compared with simultaneous rCBF measurements obtained using stable xenon-enhanced computerized tomography scanning (sXe-rCBF). The two techniques were compared using linear regression analysis as well as the Bland and Altman method. Stable TD-rCBF measurements could be obtained throughout all 3- to 5-hour sheep experiments. During
Joseph M. Messick, Brian Casement, Frank W. Sharbrough, Leslie N. Milde, John D. Michenfelder, Thoralf M. Sundt; Correlation of Regional Cerebral Blood Flow (rCBF) with EEG Changes During Isoflurane Anesthesia for Carotid Endarterectomy: Critical rCBF. Anesthesiology 1987; 66:344-349 doi: https://doi.org/10.1097/00000542-198703000-00014. Download citation file:. ...
Cerebral blood flow measurements in subarachnoid haemorrhage with an intravenous isotope technique: methodological studies : the significance of cerebral blood flow determinations in the timing of surgery of arterial aneurysm ...
Abstract. Subarachnoid hemorrhage (SAH) induces acute changes in the cerebral microcirculation. Recent findings ex vivo suggest neurovascular coupling (NVC), the process that increases cerebral blood flow upon neuronal activity, is also impaired after SAH. The aim of the current study was to investigate whether this occurs also in vivo. C57BL/6 mice were subjected to either sham surgery or SAH by filament perforation. Twenty-four hours later NVC was tested by forepaw stimulation and CO2 reactivity by inhalation of 10% CO2. Vessel diameter was assessed in vivo by two-photon microscopy. NVC was also investigated ex vivo using brain slices. Cerebral arterioles of sham-operated mice dilated to 130% of baseline upon CO2 inhalation or forepaw stimulation and cerebral blood flow (CBF) increased. Following SAH, however, CO2 reactivity was completely lost and the majority of cerebral arterioles showed paradoxical constriction in vivo and ex vivo resulting in a reduced CBF response. As previous results ...
Functional neuroimaging studies have pointed to a possible role of cerebral circuits involving the prefrontal and anterior cingulate cortices, the striatum, and thalamus in the pathophysiology of obsessive-compulsive disorder (OCD). Regional cerebral blood flow (rCBF) of 16 drug-free Brazilian patients with OCD and 17 healthy subjects matched for age, gender, handedness and level of education was measured with [99m-Tc] HMPAO single photon emission computed tomography. Analysis of covariance identified four regions of interest with significantly higher rCBF: the right superior and inferior frontal cortex and the right and left thalamus. Positive correlations between symptom severity measured by Clinical Global Impression scores and rCBF were found in the right and left inferior frontal lobes and in the right basal ganglia. Compulsive behavior was inversely correlated with rCBF in the right thalamus, and duration of illness correlated positively with rCBF in the right and left superior frontal ...
The effects of off-resonance radio-frequency irradiation on the intensity of the MR signal from water protons in the cat brain are asymmetric around the chemical shift of the water signal. This asymmetry, which could arise from a shift in the magnetization transfer spectrum approximately 1.5 ppm upfield from the solvent water signal, must be taken into account to compensate for magnetization transfer effects inherent in arterial spin tagging approaches that use a single radio-frequency coil. Two approaches that either correct for, or circumvent, the apparent upfield shift of the magnetization transfer spectrum are presented, and a perfusion image of the cat brain, using flow-induced adiabatic inversion of arterial water protons, is presented. Other problems in obtaining quantitative cerebral blood flow values using the arterial spin tagging approach are discussed.
Objective Psychological trauma leads to Post Traumatic Stress Disorder (PTSD) in susceptible subjects. The aim of this study was to investigate the differences in regional cerebral blood flow (rCBF) between two groups of subjects exposed to different types of traumatic stressor either developing or not PTSD. Method Twenty subjects developing (S) and 27 not developing (NS) PTSD after being exposed to either earlier person-under-the-train accident (NA) or being assaulted in the underground enviroment (A) were included in the study. 99mTc-HMPAO SPECT was performed and the uptake in 29 regions of the brain (VOIs), bilaterally, was assessed. rCBF distribution was compared, using analysis of variance (ANOVA), between groups (S/NS) and type (A/NA) during a situation involving an auditory evoked re-experiencing of the traumatic event. Discriminant analysis was applied to test the concordance between clinical diagnosis and SPECT findings. Results In the general analyses significant differences were found ...
Principal Investigator:Kudo Kohsuke, Project Period (FY):2014-04-01 - 2017-03-31, Research Category:Grant-in-Aid for Scientific Research (B), Section:一般, Research Field:Radiation science
TY - JOUR. T1 - Long term evaluation of brain perfusion with magnetic resonance in high flow extracranial-intracranial saphenous graft bypass. AU - Bozzao, Alessandro. AU - Fasoli, Fabrizio. AU - Finocchi, Vanina. AU - Santoro, Giuseppe. AU - Romano, Andrea. AU - Fantozzi, Luigi Maria. PY - 2007/1. Y1 - 2007/1. N2 - Assessment was made of the cerebral vascular haemodynamic parameters in patients with a high-flow extra-intracranial (EC-IC) bypass performed for therapeutic occlusion of the internal carotid artery (ICA). Sixteen patients with ICA occlusion and EC-IC bypass (time interval from surgery 1-6 years) underwent MRI. Perfusion-weighted magnetic resonance imaging (PW-MRI) sequences were performed without the use of an arterial input function. The relative cerebral blood volume (rCBV), mean transit time (MTT) and relative cerebral blood flow (rCBF) were evaluated in all patients at the level of the basal ganglia, centrum semiovale and cortex in both hemispheres. Statistically significant ...
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TY - JOUR. T1 - Brain Blood Flow Modulates the Neurotoxic Action of Hyperbaric Oxygen via Neuronal and Endothelial Nitric Oxide. AU - Moskvin, A. N.. AU - Zhilyaev, S. Yu. AU - Sharapov, O. I.. AU - Platonova, T. F.. AU - Gutsaeva, Diana Raisovna. AU - Kostkin, V. B.. AU - Demchenko, I. T.. PY - 2003/11/1. Y1 - 2003/11/1. N2 - Studies on conscious rats with inhibition of NO synthase were used to assess the dynamics of brain blood flow and EEG traces during hyperbaric oxygenation at 4 or 5 atm. Oxygen at a pressure of 4 atm induced cerebral vasoconstriction in intact animals and decreased blood flow by 11-18% (p , 0.05) during 60-min exposure to hyperbaric oxygenation. Paroxysmal EEG activity and oxygen convulsions did not occur in rats at 4 atm of O2. At 5 atm, convulsive activity appeared on the EEG at 41 ± 1.9 min, and blood flow decreased significantly during the first 20 min; blood flow increased by 23 ± 9%, as compared with controls, (p , 0.01) before the appearance of convulsions on the ...
Cardiovascular health; cerebral blood flow regulation; cerebrovascular function Dr. Philip Ainslies research is focused on the integrated mechanisms that regulate human cerebral blood flow in health and disease, the influence of environmental stress, and the effects of exercise training on cerebrovascular function.. Dr. Philip Ainslie is a Professor in the School of Health and Exercise Sciences at UBC Okanagan, the Co-Director of the Centre for Heart, Lung & Vascular Health, and an ICORD Investigator. His Ph.D. (in exercise physiology & metabolism) was a collaborative project between the Liverpool John Moores University, University of Manchester and University of Oxford. Following completion of a post-doctoral research fellowship at the University of Calgary he began a faculty position in 2005, as Lecturer and Principal Investigator in the Department of Physiology at the University of Otago, New Zealand. Here, he established his independent research program, focusing on the integrative ...
Free Online Library: Effect of backrest position on intracranial pressure and cerebral perfusion pressure in individuals with brain injury: a systematic review. by Journal of Neuroscience Nursing; Health care industry Brain injuries Care and treatment Primary care nursing Methods Primary nursing
Arterial Spin Labeling (ASL) is a non-invasive, non-contrast, perfusion imaging technique which is inherently SNR limited. It is, therefore, important to carefully design scan protocols to ensure accurate measurements. Many pseudo-continuous ASL (PCASL) protocol designs have been proposed for measuring cerebral blood flow (CBF), but it has not yet been demonstrated which design offers the most accurate and repeatable CBF measurements. In this study, a wide range of literature PCASL protocols were first optimized for CBF accuracy and then compared using Monte Carlo simulations and in vivo experiments. The protocols included single-delay, sequential and time-encoded multi-timepoint protocols, and several novel protocol designs, which are hybrids of time-encoded and sequential multi-timepoint protocols. It was found that several multi-timepoint protocols produced more confident, accurate, and repeatable CBF estimates than the single-delay protocol, while also generating maps of arterial transit time. Of
TY - JOUR. T1 - When the air hits your brain. T2 - Cerebral autoregulation of brain oxygenation during aerobic exercise allows transient hyperoxygenation: Case report. AU - Bollo, Robert J.. AU - Williams, Susan C.. AU - Peskin, Charles. AU - Samadani, Uzma. PY - 2010/8. Y1 - 2010/8. N2 - OBJECTIVE: Cerebral autoregulation maintains a relatively stable cerebral blood flow over a range of perfusion pressures. During exercise, regional cerebral blood flow may be elevated in particular areas of the brain. This case report presents the impact of aerobic exercise on intracranially measured pressure and brain tissue oxygenation in an adult human. CLINCIAL PRESENTATION: A 30-year-old man with idiopathic intracranial hypertension treated with cerebrospinal fluid diversion was monitored with a Licox intracranial brain oxygen and pressure monitor (Integra NeuroSciences Corporation, Plainsboro, New Jersey) for refractory nonpostural headaches exacerbated after exercise. He performed trials of running and ...
Cerebral blood flow (CBF) and oxygenation (COx) are generally well-preserved in COPD. It is unknown whether prevalent cardiovascular co-morbidities, such as heart failure, may impair CBF and COx responses to exertion. Eighteen males with moderate-to-severe COPD (8 with and 10 without overlapping heart failure) underwent a progressive exercise test with pre-frontal CBF and COx measurements (indocyanine green and near-infrared spectroscopy). Mean arterial pressure and cardiac output were lower from rest to exercise in overlap. Only COPD patients demonstrated an increase in arterialized PCO2 towards the end of progressive exercise. CBF index was consistently higher and increased further by similar to 40% during exercise in COPD whereas a similar to 10% reduction was observed in overlap. COx was lower in overlap despite preserved arterial oxygenation. In conclusion, heart failure introduces pronounced negative effects on CBF and COx in COPD which may be associated with clinically relevant outcomes, ...
The mechanism of action of vinpocetine is composed of several elements: it improves cerebral blood flow and metabolism, has a beneficial effect on the rheological properties of blood. The neuroprotective action is realized by reducing the adverse cytotoxic effect of excitatory amino acids. Improves the exchange of serotonin and norepinephrine in the brain, it stimulates the noradrenergic neurotransmitter systems and has an antioxidant effect. It improves the microcirculation in the brain by inhibiting platelet aggregation, reducing the pathologically increased blood viscosity, increase the deformability of red blood cells and the inhibition of the reuptake of adenoeina; promotes oxygen transfer into the cells by reducing the affinity of erythrocytes thereto. Selectively increases cerebral blood flow by reducing the cerebral vascular resistance without a significant impact on system performance circulatory (blood pressure (BP), cardiac output, heart rate, total peripheral vascular resistance); It ...
| Arterial spin labeling (ASL) MRI, which measures cerebral blood flow, could act as a biomarker in Alzheimers disease. Abstract | GE Healthcare ($GE) company Clarient Diagnostic Services...
TY - JOUR. T1 - Dynamic pressure - Flow relationship of the cerebral circulation during acute increase in arterial pressure. AU - Zhang, Rong. AU - Behbehani, Khosrow. AU - Levine, Benjamin D.. PY - 2009. Y1 - 2009. N2 - The physiological mechanism(s) for the regulation of the dynamic pressure-flow relationship of the cerebral circulation are not well understood. We studied the effects of acute cerebral vasoconstriction on the transfer function between spontaneous changes in blood pressure (BP) and cerebral blood flow velocity (CBFV) in 13 healthy subjects (30 ± 7 years). CBFV was measured in the middle cerebral artery using transcranial Doppler. BP was increased stepwise with phenylephrine infusion at 0.5, 1.0 and 2.0 μg kg-1 min-1. Phenylephrine increased BP by 11, 23 and 37% from baseline, while CBFV increased (11%) only with the highest increase in BP. Cerebrovascular resistance index (BP/CBFV) increased progressively by 6, 17 and 23%, demonstrating effective steady-state autoregulation. ...
TY - JOUR. T1 - Endothelial influences on cerebrovascular tone. AU - Andresen, Jon. AU - Shafi, Nadeem. AU - Bryan, Robert M.. PY - 2006/1/1. Y1 - 2006/1/1. N2 - The cerebrovascular endothelium exerts a profound influence on cerebral vessels and cerebral blood flow. This review summarizes current knowledge of various dilator and constrictor mechanisms intrinsic to the cerebrovascular endothelium. The endothelium contributes to the resting tone of cerebral arteries and arterioles by tonically releasing nitric oxide (NO • ). Dilations can occur by stimulated release of NO • , endothelium-derived hyperpolarization factor, or prostanoids. During pathological conditions, the dilator influence of the endothelium can turn to that of constriction by a variety of mechanisms, including decreased NO • bioavailability and release of endothelin-1. The endothelium may participate in neurovascular coupling by conducting local dilations to upstream arteries. Further study of the cerebrovascular ...
FIG. 1. Regional cerebral blood flow changes during hypoglycemia illustrating greater synaptic activity in bilateral dorsal midline thalamus on day 2, following ∼24 h of interval interprandial hypoglycemia, compared with day 1. These are combined subtraction images from all PET scans from all nine subjects superimposed on the combined MR image. The color scales show changes relative to mean global blood flow. A maximum of 12% is used for all scales. However, the maximum change for day 2 was 18% compared with 10% on day 1. A: Mid-sagittal slices. B: Coronal slices at the level of the paraventricular nuclei (y = −19) with the left of the brain on the left (33). ...
By mapping the dynamics of brain reorganization, functional magnetic resonance imaging MRI (fMRI) has allowed for significant progress in understanding cerebral plasticity phenomena after a stroke. However, cerebro-vascular diseases can affect blood oxygen level dependent (BOLD) signal. Cerebral autoregulation is a primary function of cerebral hemodynamics, which allows to maintain a relatively constant blood flow despite changes in arterial blood pressure and perfusion pressure. Cerebral autoregulation is reported to become less effective in the early phases post-stroke. This study investigated whether any impairment of cerebral hemodynamics that occurs during the acute and the subacute phases of ischemic stroke is related to changes in BOLD response. We enrolled six aphasic patients affected by acute stroke. All patients underwent a Transcranial Doppler to assess cerebral autoregulation (Mx index) and fMRI to evaluate the amplitude and the peak latency (time to peak-TTP) of BOLD response in the acute