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https://www.readbyqxmd.com/read/28925529/cerebrovascular-response-to-the-cold-pressor-test-the-critical-role-of-carbon-dioxide
#1
Michael M Tymko, Thijs P Kerstens, Kevin W Wildfong, Philip N Ainslie
In addition to increasing sympathetic nervous activity, blood pressure, and cerebral blood flow (CBF), the cold pressor test (CPT) stimulates pain receptors, which may increase ventilation above metabolic demand; this response likely reduces the partial pressure of end-tidal carbon dioxide (PET CO2 ), and will attenuate elevations in CBF. We hypothesized: (1) CPT would elicit hyperventilation, effectively lowering PET CO2 ; (2) the CBF response will be elevated during an isocapnic (controlled PET CO2 ), compared to a poikilocapnic CPT (uncontrolled PET CO2 ); (3) In response to CPT, the common carotid artery (CCA) will vasodilatate, while the internal carotid artery (ICA) will remain unchanged to help regulate CBF...
September 19, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28919267/post-carotid-endarterectomy-hypertension-part-2-association-with-peri-operative-clinical-anaesthetic-and-transcranial-doppler-derived-parameters
#2
Jeremy E Newman, Mathew J Bown, Robert D Sayers, Jonathan P Thompson, Thompson G Robinson, Bryan Williams, Ronney Panerai, Peter Lacy, A Ross Naylor
OBJECTIVE/BACKGROUND: The first paper in this series observed that pre-operative baroreceptor dysfunction and poorly controlled hypertension were independently predictive for identifying patients who went on to require treatment for post-endarterectomy hypertension (PEH). The second paper examines the influence of intra-operative patient, transcranial Doppler (TCD) ultrasound, and anaesthetic variables on the incidence of PEH. METHODS: In total, 106 patients underwent carotid endarterectomy (CEA) under general anaesthesia...
September 14, 2017: European Journal of Vascular and Endovascular Surgery
https://www.readbyqxmd.com/read/28918088/evaluation-of-cerebrovascular-reactivity-in-subjects-with-and-without-obstructive-sleep-apnea
#3
Clodagh M Ryan, Anne Battisti-Charbonney, Olivia Sobczyk, David J Mikulis, James Duffin, Joseph A Fisher, Lashmi Venkatraghavan
BACKGROUND: Both obstructive sleep apnea (OSA) and altered cerebrovascular reactivity (CVR) are associated with increased stroke risk. Nevertheless, the incidence of abnormal CVR in patients with OSA is uncertain due to the high variability in the way CVR is measured both within and between studies. We hypothesized that a standardized CVR with a consistent vasoactive stimulus and cerebral blood flow (CBF) measure would be reduced in patients with severe OSA compared with healthy controls...
September 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28912128/aging-modifies-the-effect-of-cardiac-output-on-middle-cerebral-artery-blood-flow-velocity
#4
Anne-Sophie G T Bronzwaer, Jasper Verbree, Wim J Stok, Mat J A P Daemen, Mark A van Buchem, Matthias J P van Osch, Johannes J van Lieshout
An association between cerebral blood flow (CBF) and cardiac output (CO) has been established in young healthy subjects. As of yet it is unclear how this association evolves over the life span. To that purpose, we continuously recorded mean arterial pressure (MAP; finger plethysmography), CO (pulse contour; CO-trek), mean blood flow velocity in the middle cerebral artery (MCAV; transcranial Doppler ultrasonography), and end-tidal CO2 partial pressure (PetCO2) in healthy young (19-27 years), middle-aged (51-61 years), and elderly subjects (70-79 years)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904950/quantitative-changes-in-cerebral-perfusion-during-urinary-urgency-in-women-with-overactive-bladder
#5
Nisha G Arya, Steven J Weissbart, Sihua Xu, Rupal Bhavsar, Hengyi Rao
PURPOSE: To quantitatively measure changes in cerebral perfusion in select regions of interest in the brain during urinary urgency in women with overactive bladder (OAB) using arterial spin labeling (ASL). METHODS: Twelve women with OAB and 10 controls underwent bladder filling and rated urinary urgency (scale 0-10). ASL fMRI scans were performed (1) in the low urgency state after voiding and (2) high urgency state after drinking oral fluids. Absolute regional cerebral blood flow (rCBF) in select regions of interest was compared between the low and high urgency states...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28900720/respiration-related-cerebral-blood-flow-variability-increases-during-control-mode-non-invasive-ventilation-in-normovolemia-and-hypovolemia
#6
Maria Skytioti, Signe Søvik, Maja Elstad
PURPOSE: Increased variability in cerebral blood flow (CBF) predisposes to adverse cerebrovascular events. Oscillations in arterial blood pressure and PaCO2 induce CBF variability. Less is known about how heart rate (HR) variability affects CBF. We experimentally reduced respiration-induced HR variability in healthy subjects, hypothesizing that CBF variability would increase. METHODS: Internal carotid artery (ICA) blood velocity was recorded by Doppler ultrasound in ten healthy subjects during baseline, control-mode, non-invasive mechanical ventilation (NIV), i...
September 12, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28894559/pattern-of-cerebral-blood-flow-velocity-using-transcranial-doppler-ultrasonography-in-children-with-sickle-cell-disorder-in-lagos-state-nigeria
#7
Motunrayo Oluwabukola Adekunle, Adeola Barakat Animasahun, Ijeoma Nnenna Diaku-Akinwumi, Olisamedua Fidelis Njokanma
Cerebrovascular accident (CVA) is a common, devastating neurological complication of sickle cell disorder (SCD) with a high recurrent and mortality rate. The Stroke Prevention Trial in Sickle Cell Anaemia study (STOP) recommends routine screening with transcranial Doppler ultrasonography in children aged two to sixteen years with SCD. The present study assessed cerebral blood flow velocities of children with SCD in accordance with the recommendation of routine screening by the STOP study. METHODS: Transcranial Doppler ultrasonography was done for children with SCD that attended Sickle Cell Foundation, Nigeria between July and November 2015...
2017: Mediterranean Journal of Hematology and Infectious Diseases
https://www.readbyqxmd.com/read/28893764/prevalence-of-cerebral-microbleeds-in-patients-with-continuous-flow-left-ventricular-assist-devices
#8
Daisuke Yoshioka, Shuhei Okazaki, Koichi Toda, Sho Murase, Shunsuke Saito, Keitaro Domae, Shigeru Miyagawa, Yasushi Yoshikawa, Takashi Daimon, Manabu Sakaguchi, Yoshiki Sawa
BACKGROUND: The prevalence of cerebral microbleeds (CMBs) in gradient echo T2*-weighted brain MRI has a positive correlation with hemorrhagic stroke incidence. However, the prevalence of CMBs in patients with left ventricular assist devices (LVADs) has not been evaluated. We evaluated the prevalence of CMBs and the relationship with hemorrhagic stroke incidence in patients with LVADs. METHOD AND RESULTS: We analyzed results from brain MRI in prospective examinations of 35 consecutive patients who had undergone LVAD explantation for heart transplantation or recovery since 2011...
September 11, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28891839/the-relative-effects-of-dexmedetomidine-and-propofol-on-cerebral-blood-flow-velocity-and-regional-brain-oxygenation-a-randomised-noninferiority-trial
#9
Ehab Farag, Michael Kot, Attila Podolyak, Maged Argalious, Milind Deogaonkar, Edward J Mascha, Zekun Xu, Irene Katzan, Zeyd Ebrahim
BACKGROUND: Dexmedetomidine constricts cerebral blood vessels without a concomitant reduction in cerebral metabolic oxygen consumption. Its safety as a sedative in patients with neurological diseases thus remains uncertain. OBJECTIVE: Our primary objective was to test the hypothesis that dexmedetomidine is noninferior to propofol as regards cerebral blood flow (CBF) velocity and brain oxygenation. DESIGN: Unblinded randomised trial. SETTING: Cleveland Clinic Hospital, Cleveland, from November 2010 to July 2013...
June 19, 2017: European Journal of Anaesthesiology
https://www.readbyqxmd.com/read/28887332/the-cerebro-cardiovascular-response-to-periodic-squat-stand-maneuvers-in-healthy-subjects-a-time-domain-analysis
#10
Sam C Barnes, Naomi Ball, Victoria Joanna Haunton, Thompson G Robinson, Ronney B Panerai
BACKGROUND: Squat-stand maneuvers (SSMs) have been used to improve the coherence of transfer function analysis (TFA) estimates during the assessment of dynamic cerebral autoregulation (dCA). There is a need to understand the influence of peripheral changes resulting from SSMs on cerebral blood flow, which might confound estimates of dCA. METHODS: 29 healthy subjects underwent recordings at rest (5 min standing) and 15 SSMs (0.05Hz). Heart rate (3-lead ECG), end-tidal CO2 (capnography), blood pressure (Finometer), cerebral blood velocity (CBV, transcranial Doppler, MCA) and the angle of the thigh (tilt sensor) were measured continuously...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28879895/perfusion-mr-imaging-of-enhancing-brain-tumors-comparison-of-arterial-spin-labeling-technique-with-dynamic-susceptibility-contrast-technique
#11
Neetu Soni, Devender Pal S Dhanota, Sunil Kumar, Awadhesh K Jaiswal, Arun K Srivastava
OBJECTIVE: Arterial spin labeling (ASL) magnetic resonance (MR) perfusion is a noninvasive and repeatable method for quantitatively measuring cerebral blood flow (CBF). This study aims to compare measurements of ASL-derived CBF with dynamic susceptibility contrast (DSC) MRI in the assessment of enhancing brain tumors (primary and metastatic), with an aim to use ASL as an alternative to DSC. MATERIALS AND METHODS: Thirty patients with newly diagnosed brain tumors (16 meningiomas, 6 gliomas, 3 metastases, 2 cerebellopontine angle schwannoma, 1 central neurocytoma, and 2 low-grade gliomas) were examined using a 3T MR scanner...
September 2017: Neurology India
https://www.readbyqxmd.com/read/28877097/application-of-transcranial-color-doppler-ultrasonography-for-assessing-middle-cerebral-arteries-in-rheumatoid-arthritis
#12
Qiuyue Chen, Shilin Li, Guorong Lv, Yanchun Zhao
To assess the role of ultrasonography for assessing middle cerebral arteries (MCAs) in rheumatoid arthritis (RA). Middle cerebral arteries of 32 RA patients and 32 healthy volunteers were examined by ultrasonography. Peak systolic blood flow velocity (PSV), end-diastolic velocity, and resistance index (RI) of MCA were measured using Doppler ultrasound. Results were expressed as mean ± SD. No significant difference in peak systolic velocity was obtained between RA patients (52.44 ± 19.56 cm/s) and healthy volunteers (51...
September 4, 2017: Ultrasound Quarterly
https://www.readbyqxmd.com/read/28867670/reduced-distortion-artifact-whole-brain-cbf-mapping-using-blip-reversed-non-segmented-3d-echo-planar-imaging-with-pseudo-continuous-arterial-spin-labeling
#13
Neville D Gai, Yi Yu Chou, Dzung Pham, John A Butman
PURPOSE: To implement and evaluate interleaved blip-up, blip-down, non-segmented 3D echo planar imaging (EPI) with pseudo-continuous arterial spin labeling (pCASL) and post-processing for reduced susceptibility artifact cerebral blood flow (CBF) maps. MATERIALS AND METHODS: 3D EPI non-segmented acquisition with a pCASL labeling sequence was modified to include alternating k-space coverage along phase encoding direction (referred to as "blip-reversed") for alternating dynamic acquisitions of control and label pairs...
September 1, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28862474/tympanic-membrane-temperature-decreases-during-head-up-tilt-relation-to-frontal-lobe-oxygenation-and-middle-cerebral-artery-mean-blood-flow-velocity
#14
David Lorr, Anton Lund, Mats Fredrikson, Niels H Secher
INTRODUCTION: Changes in blood flow influence temperature of surrounding tissues. Since the internal carotid artery (ICA) and internal jugular vein (IJV) neighbor the tympanic membrane, changes in their blood flow most likely determine changes in tympanic membrane temperature (TMT). We sought to evaluate the relationship between changes during a head-up tilt (HUT) induced reduction in cerebral blood flow (CBF) and TMT. METHODS: Ten male subjects (age 19-28 years) underwent 50° HUT until presyncope...
September 1, 2017: Scandinavian Journal of Clinical and Laboratory Investigation
https://www.readbyqxmd.com/read/28861934/indirect-mri-of-17-o-labeled-water-using-steady-state-sequences-signal-simulation-and-preclinical-experiment
#15
Kohsuke Kudo, Taisuke Harada, Hiroyuki Kameda, Ikuko Uwano, Fumio Yamashita, Satomi Higuchi, Kunihiro Yoshioka, Makoto Sasaki
BACKGROUND: Few studies have been reported for T2 -weighted indirect (17) O imaging. PURPOSE/HYPOTHESIS: To evaluate the feasibility of steady-state sequences for indirect (17) O brain imaging. STUDY TYPE: Signal simulation, phantom measurements, and prospective animal experiments were performed in accordance with the institutional guidelines for animal experiments. POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODEL: Signal simulations of balanced steady-state free precession (bSSFP) were performed for concentrations of (17) O ranging from 0...
August 31, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28861407/alterations-in-cerebral-blood-flow-after-resuscitation-from-cardiac-arrest
#16
REVIEW
Bistra Iordanova, Lingjue Li, Robert S B Clark, Mioara D Manole
Greater than 50% of patients successfully resuscitated from cardiac arrest have evidence of neurological disability. Numerous studies in children and adults, as well as in animal models have demonstrated that cerebral blood flow (CBF) is impaired after cardiac arrest. Stages of cerebral perfusion post-resuscitation include early hyperemia, followed by hypoperfusion, and finally either resolution of normal blood flow or protracted hyperemia. At the level of the microcirculation the blood flow is heterogeneous, with areas of no flow, low flow, and increased flow...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28853610/white-matter-hyperintensities-in-migraine-clinical-significance-and-central-pulsatile-hemodynamic-correlates
#17
Chun-Yu Cheng, Hao-Min Cheng, Shih-Pin Chen, Chih-Ping Chung, Yung-Yang Lin, Han-Hwa Hu, Chen-Huan Chen, Shuu-Jiun Wang
Background The role of central pulsatile hemodynamics in the pathogenesis of white matter hyperintensities in migraine patients has not been clarified. Methods Sixty patients with migraine (20-50 years old; women, 68%) without overt vascular risk factors and 30 demographically-matched healthy controls were recruited prospectively. Cerebral white matter hyperintensities volume was determined by T1-weighted magnetic resonance imaging with CUBE-fluid-attenuated-inversion-recovery sequences. Central systolic blood pressure, carotid-femoral pulse wave velocity, and carotid augmentation index were measured by applanation tonometry...
January 1, 2017: Cephalalgia: An International Journal of Headache
https://www.readbyqxmd.com/read/28845537/cerebral-blood-flow-velocities-and-cerebrovascular-resistance-in-normal-term-neonates-in-the-first-72-hours
#18
Danielle E Forster, Emmanuel Koumoundouros, Virginia Saxton, Gabrielle Fedai, James Holberton
AIM: To determine the range of cerebral blood flow velocities (CBFVs) and Doppler indices of cerebrovascular resistance in normal-term neonates as a baseline for a study of hypoxic-ischaemic encephalopathy. METHODS: The CBFVs, resistive index (RI) and pulsatility index (PI) were measured in the anterior and middle cerebral arteries (ACA and MCA) of 38 normal neonates. RESULTS: The mean peak systolic, end diastolic and time-averaged velocities (PSV, EDV and TAV) were 36...
August 28, 2017: Journal of Paediatrics and Child Health
https://www.readbyqxmd.com/read/28845175/microstructural-abnormalities-of-basal-ganglia-and-thalamus-in-bipolar-and-unipolar-disorders-a-diffusion-kurtosis-and-perfusion-imaging-study
#19
Lianping Zhao, Ying Wang, Yanbin Jia, Shuming Zhong, Yao Sun, Zhifeng Zhou, Zhongping Zhang, Li Huang
OBJECTIVE: Bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in subcorticalgray matter regions between BD and UD. METHODS: Thirty-five BD patients, 30 UD patients and 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr) and cerebral blood flow (CBF) were measured by using regions-of-interest analysis in the caudate, putamen and thalamus of the subcortical gray matter regions...
July 2017: Psychiatry Investigation
https://www.readbyqxmd.com/read/28844934/low-cerebral-blood-flow-after-cardiac-arrest-is-not-associated-with-anaerobic-cerebral-metabolism
#20
Cornelia W Hoedemaekers, Philip N Ainslie, Stijn Hinssen, Marcel J Aries, Laurens L Bisschops, Jeannette Hofmeijer, Johannes G van der Hoeven
AIM OF THE STUDY: Estimation of cerebral anaerobic metabolism in survivors and non-survivors after cardiac arrest. METHODS: We performed an observational study in twenty comatose patients after cardiac arrest and 19 healthy control subjects. We measured mean flow velocity in the middle cerebral artery (MFVMCA) by transcranial Doppler. Arterial and jugular blood samples were used for calculation of the jugular venous-to-arterial CO2/arterial to-jugular venous O2 content difference ratio...
August 24, 2017: Resuscitation
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