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Mean cerebral blood flow

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https://www.readbyqxmd.com/read/28239641/macrovascular-and-microvascular-cerebral-blood-flow-in-adults-at-risk-for-alzheimer-s-disease
#1
Lindsay R Clark, Sara E Berman, Leonardo A Rivera-Rivera, Siobhan M Hoscheidt, Burcu F Darst, Corinne D Engelman, Howard A Rowley, Cynthia M Carlsson, Sanjay Asthana, Patrick Turski, Oliver Wieben, Sterling C Johnson
INTRODUCTION: Capillary hypoperfusion is reported in asymptomatic adults at-risk for Alzheimer's disease (AD), but the extent that can be explained by reduced flow in intracranial arteries is unknown. METHODS: One hundred fifty-five asymptomatic adults enriched for AD risk (mean age 61 years) completed arterial spin labeling (pcASL) and 4D-flow MRI sequences. Voxel-wise regression models investigated the relationship between mean flow in bilateral cerebral arteries and capillary perfusion, and tested potential moderators of this relationship...
2017: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring
https://www.readbyqxmd.com/read/28226593/dynamic-cerebral-autoregulation-in-young-athletes-following-concussion
#2
Kyriaki Kostoglou, Alexander D Wright, Jonathan D Smirl, Kelsey Bryk, Paul van Donkelaar, Georgios D Mitsis, Kyriaki Kostoglou, Alexander D Wright, Jonathan D Smirl, Kelsey Bryk, Paul van Donkelaar, Georgios D Mitsis, Paul van Donkelaar, Alexander D Wright, Kyriaki Kostoglou, Jonathan D Smirl, Kelsey Bryk, Georgios D Mitsis
The purpose of this study was to examine cerebral autoregulation (CA) in young athletes experiencing concussion. The subjects were monitored and repeatedly tested 72 hours, 2 weeks and 1 month post-injury. Mean arterial blood pressure (MABP), end-tidal partial pressure of carbon dioxide (PETCO2) and cerebral blood flow velocity (CBFV) in the middle and posterior cerebral arteries were monitored during mental activation paradigms. In order to characterize CA we employed autoregressive models with exogenous inputs (ARX) and impulse response models based on the Laguerre expansion technique (LET)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28219193/-analysis-of-ct-perfusion-imaging-in-chronic-cerebral-circulatory-insufficiency-and-its-relationship-with-crossed-cerebellar-diaschisis
#3
S L Liu, Y Wang, Y Zhang, H L Xu, J C Wang, W W He, X T Qin, G Q Cao, Y J Yang, Q C Zhuge, W J Chen
Objective: To investigate the change of cerebral microcirculation of chronic cerebral circulation insufficiency(CCCI) patients and the relationship between CCCI and crossed cerebellar diaschisis(CCD)by using 320-detector row of low-dose volume CT perfusion imaging. Methods: A total of 158 patients (103 males, 55 females, from 45 to 82 years old, the mean age was 62.9) with symptoms of CCCI were admitted to the First Affiliated Hospital of Wenzhou Medical University from June 2013 to January 2016. Low-dose CTP imaging of whole brain was performed to them using 320-detector row volume CT scanner...
February 7, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/28217385/silent-ischemic-lesion-laterality-in-asymptomatic-internal-carotid-artery-stenosis-relates-to-reduced-cerebral-vasoreactivity
#4
Makoto Isozaki, Hiroharu Kataoka, Kazuhito Fukushima, Hatsue Ishibashi-Ueda, Naoaki Yamada, Hidehiro Iida, Koji Iihara
BACKGROUND: We investigated the relationship between silent ischemic lesions, defined as hyperintense lesions on T2-weighted magnetic resonance imaging scans of brain white matter and cerebral hemodynamics (baseline cerebral blood flow and cerebral vasoreactivity). METHODS: Between January 2007 and December 2012, 61 patients with asymptomatic internal carotid artery stenosis were evaluated for asymptomatic silent ischemic lesions, acute infarction, and cerebral hemodynamics...
2017: Surgical Neurology International
https://www.readbyqxmd.com/read/28216521/technique-and-theory-of-hollow-fiber-phantom-for-cerebral-ct-perfusion
#5
Eiji Okaniwa, Hiroyuki Hashimoto, Kazufumi Suzuki, Hiroshi Iimura, Shingo Suzaki, Kayoko Abe, Mituhiro Ejima, Shuji Sakai
We developed a phantom using a hollow-fiber hemodialyzer to evaluate the quantitative reliability of cerebral computed tomography (CT) perfusion. Our phantom consisted of a hollow-fiber hemodialyzer and a syringe-shaped X-ray device made up of resin. The phantom can give theoretical true values for cerebral blood volume, cerebral blood flow, and mean transit time. We compared the values measured in the phantom with predicted theoretical values. The purpose of the current report is to describe the theory and experimental technique used to obtain an absolute value in a phantom...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28215270/decreased-cerebral-vasomotor-reactivity-in-patients-with-obstructive-sleep-apnea-syndrome
#6
Oguzhan Oz, Serdar Tasdemir, Hakan Akgun, Murat Erdem, Adem Balikci, Ahmet Cetiz, Mehmet Yucel, Umit Hidir Ulas, Seref Demirkaya, Yasar Kutukcu, Fuat Özgen
OBJECTIVE: In obstructive sleep apnea syndrome (OSAS), any of the activated neural, vascular, hemodynamic, metabolic, inflammatory, and thrombotic mechanisms may be related to increased cerebrovascular disease and risk of death; however, the possible pathophysiological process between obstructive sleep apnea syndrome and stroke has not been clearly explained. We hypothesize that alterations in vasomotor reactivity in patients may be responsible for their altered cerebral blood flow, and may contribute to the increased risk of ischemic stroke...
February 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28214930/investigation-of-optical-neuro-monitoring-technique-for-detection-of-maintenance-and-emergence-states-during-general-anesthesia
#7
Gabriela Hernandez-Meza, Meltem Izzetoglu, Mary Osbakken, Michael Green, Hawa Abubakar, Kurtulus Izzetoglu
The American Society of Anesthesiologist recommends peripheral physiological monitoring during general anesthesia, which offers no information regarding the effects of anesthetics on the brain. Since no "gold standard" method exists for this evaluation, such a technique is needed to ensure patient comfort, procedure quality and safety. In this study we investigated functional near infrared spectroscopy (fNIRS) as possible monitor of anesthetic effects on the prefrontal cortex. Anesthetic drugs, such as sevoflurane, suppress the cerebral metabolism and alter the cerebral blood flow...
February 18, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28210922/resting-cerebral-blood-flow-alteration-in-severe-obstructive-sleep-apnoea-an-arterial-spin-labelling-perfusion-fmri-study
#8
Si Nie, De-Chang Peng, Hong-Han Gong, Hai-Jun Li, Li-Ting Chen, Cheng-Long Ye
STUDY OBJECTIVES: The aim of this study is to investigate changes in regional cerebral blood flow (rCBF) in awake people with untreated severe obstructive sleep apnoea (OSAs) compared with good sleepers (GSs). DESIGN: Arterial spin labelling perfusion imaging was used to quantify cerebral perfusion based on resting-state functional magnetic resonance imaging (MRI). SETTING: Lying supine in a 3.0-T magnetic resonance imaging scanner in the night was done...
February 16, 2017: Sleep & Breathing, Schlaf & Atmung
https://www.readbyqxmd.com/read/28209740/quantitative-mri-volumetry-diffusivity-cerebrovascular-flow-and-cranial-hydrodynamics-during-head-down-tilt-and-hypercapnia-the-spacecot-study
#9
Larry Allen Kramer, Khader M Hasan, Ashot E Sargsyan, Karina Marshall-Goebel, Jörn Rittweger, Dorit Donoviel, Saki Higashi, Benson Mwangi, Darius A Gerlach, Eric M Bershad
PURPOSE: In order to improve the pathophysiologic understanding of visual changes observed in astronauts, we aimed to use quantitative MRI to measure anatomic and physiologic responses during a ground-based spaceflight analogue (head down tilt, HDT) combined with increased ambient carbon dioxide (CO2). METHODS: Six healthy, male subjects participated in the double-blinded, randomized cross-over design study with two conditions: 26.5 h of -12° HDT with ambient air and with 0...
February 16, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28207907/argon-does-not-affect-cerebral-circulation-or-metabolism-in-male-humans
#10
Frank Grüne, Stephan Kazmaier, Sanne Elisabeth Hoeks, Robert Jan Stolker, Marc Coburn, Andreas Weyland
OBJECTIVE: Accumulating data have recently underlined argon´s neuroprotective potential. However, to the best of our knowledge, no data are available on the cerebrovascular effects of argon (Ar) in humans. We hypothesized that argon inhalation does not affect mean blood flow velocity of the middle cerebral artery (Vmca), cerebral flow index (FI), zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe), resistance area product (RAP) and the arterio-jugular venous content differences of oxygen (AJVDO2), glucose (AJVDG), and lactate (AJVDL) in anesthetized patients...
2017: PloS One
https://www.readbyqxmd.com/read/28193707/arterial-pressure-heart-rate-and-cerebral-hemodynamics-across-the-adult-life-span
#11
Chang-Yang Xing, Takashi Tarumi, Rutger L Meijers, Marcel Turner, Justin Repshas, Li Xiong, Kan Ding, Wanpen Vongpatanasin, Li-Jun Yuan, Rong Zhang
Age-related alterations in systemic and cerebral hemodynamics are not well understood. The purpose of this study is to characterize age-related alterations in beat-to-beat oscillations in arterial blood pressure (BP), heart rate (HR), cerebral blood flow (CBF), cardiac baroreflex sensitivity, and dynamic cerebral autoregulation across the adult life span. We studied 136 healthy adults aged 21 to 80 years (60% women). Beat-to-beat BP, HR, and CBF velocity were measured at rest and during sit-stand maneuvers to mimic effects of postural changes on BP and CBF...
February 13, 2017: Hypertension
https://www.readbyqxmd.com/read/28188214/transcranial-doppler-determined-change-in-posterior-cerebral-artery-blood-flow-velocity-does-not-reflect-vertebral-artery-blood-flow-during-exercise
#12
Takuro Washio, Hiroyuki Sasaki, Shigehiko Ogoh
We examined whether a change in posterior cerebral artery flow velocity (PCAv) reflected the posterior cerebral blood flow, in healthy subjects, during both static and dynamic exercise. PCAv and vertebral artery (VA) blood flow, as an index of posterior blood flow, were continuously measured during an exercise trial, using transcranial Doppler (TCD) ultrasonography and Doppler ultrasound, respectively. Static handgrip exercise significantly increased both PCAv and VA blood flow. Increasing intensity of dynamic exercise further increased VA blood flow from moderate exercise, while PCAv decreased to almost resting level...
February 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28186661/brain-neurochemical-and-hemodynamic-findings-in-the-ny1dd-mouse-model-of-mild-sickle-cell-disease
#13
Min-Hui Cui, Sandra M Suzuka, Nicholas A Branch, Kamalakar Ambadipudi, Sangeetha Thangaswamy, Seetharama A Acharya, Henny H Billett, Craig A Branch
To characterize the cerebral profile associated with sickle cell disease (SCD), we used in vivo proton MRI and MRS to quantify hemodynamics and neurochemicals in the thalamus of NY1DD mice, a mild model of SCD, and compared them with wild-type (WT) control mice. Compared with WT mice, NY1DD mice at steady state had elevated cerebral blood flow (CBF) and concentrations of N-acetylaspartate (NAA), glutamate (Glu), alanine, total creatine and N-acetylaspartylglutamate. Concentrations of glutathione (GSH) at steady state showed a negative correlation with BOLD signal change in response to 100% oxygen, a marker for oxidative stress, and mean diffusivity assessed using diffusion-tensor imaging, a marker for edematous inflammation...
February 10, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28186430/cerebral-blood-flow-frontal-lobe-oxygenation-and-intra-arterial-blood-pressure-during-sprint-exercise-in-normoxia-and-severe-acute-hypoxia-in-humans
#14
David Curtelin, David Morales-Alamo, Rafael Torres-Peralta, Peter Rasmussen, Marcos Martin-Rincon, Mario Perez-Valera, Christoph Siebenmann, Ismael Pérez-Suárez, Evgenia Cherouveim, A William Sheel, Carsten Lundby, José Al Calbet
Cerebral blood flow (CBF) is regulated to secure brain O2 delivery while simultaneously avoiding hyperperfusion; however, both requisites may conflict during sprint exercise. To determine whether brain O2 delivery or CBF is prioritized, young men performed sprint exercise in normoxia and hypoxia (PIO2 = 73 mmHg). During the sprints, cardiac output increased to ∼22 L min(-1), mean arterial pressure to ∼131 mmHg and peak systolic blood pressure ranged between 200 and 304 mmHg. Middle-cerebral artery velocity (MCAv) increased to peak values (∼16%) after 7...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28181842/the-effects-of-hypercapnia-on-cortical-capillary-transit-time-heterogeneity-cth-in-anesthetized-mice
#15
Eugenio Gutiérrez-Jiménez, Hugo Angleys, Peter Mondrup Rasmussen, Irene Klærke Mikkelsen, Kim Mouridsen, Leif Østergaard
Capillary flow patterns are highly heterogeneous in the resting brain. During hyperemia, capillary transit-time heterogeneity (CTH) decreases, in proportion to blood's mean transit time (MTT) in passive, compliant microvascular networks. Previously, we found that functional activation reduces the CTH:MTT ratio, suggesting that additional homogenization takes place through active neurocapillary coupling mechanisms. Here, we examine changes in the CTH:MTT ratio during hypercapnic hyperemia in anesthetized mice (C57Bl/6NTac), expecting that homogenization is smaller than during functional hyperemia...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28179559/acute-cerebral-venous-thrombosis-three-dimensional-visualization-and-quantification-of-hemodynamic-alterations-using-4-dimensional-flow-magnetic-resonance-imaging
#16
Florian Schuchardt, Anja Hennemuth, Laure Schroeder, Stephan Meckel, Michael Markl, Thomas Wehrum, Andreas Harloff
BACKGROUND AND PURPOSE: Cerebral venous thrombosis (CVT) affects venous hemodynamics and can provoke severe stroke and chronic intracranial hypertension. We sought to comprehensively analyze 3-dimensional blood flow and hemodynamic alterations during acute CVT including collateral recruitment and at follow-up. METHODS: Twenty-two consecutive patients with acute CVT were prospectively included and underwent routine brain magnetic resonance imaging (MRI) and 4-dimensional flow MRI at 3 T for the in vivo assessment of cerebral blood flow...
February 8, 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28161877/minimizing-the-blood-velocity-differences-between-phase-contrast-magnetic-resonance-imaging-and-computational-fluid-dynamics-simulation-in-cerebral-arteries-and-aneurysms
#17
Mohd Azrul Hisham Mohd Adib, Satoshi Ii, Yoshiyuki Watanabe, Shigeo Wada
The integration of phase-contrast magnetic resonance images (PC-MRI) and computational fluid dynamics (CFD) is a way to obtain detailed information of patient-specific hemodynamics. This study proposes a novel strategy for imposing a pressure condition on the outlet boundary (called the outlet pressure) in CFD to minimize velocity differences between the PC-MRI measurement and the CFD simulation, and to investigate the effects of outlet pressure on the numerical solution. The investigation involved ten patient-specific aneurysms reconstructed from a digital subtraction angiography image, specifically on aneurysms located at the bifurcation region...
February 4, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28149675/computer-simulation-of-cerebral-arteriovenous-malformation-validation-analysis-of-hemodynamics-parameters
#18
Y Kiran Kumar, Shashi Bhushan Mehta, Manjunath Ramachandra
PROBLEM: The purpose of this work is to provide some validation methods for evaluating the hemodynamic assessment of Cerebral Arteriovenous Malformation (CAVM). This article emphasizes the importance of validating noninvasive measurements for CAVM patients, which are designed using lumped models for complex vessel structure. METHODS: The validation of the hemodynamics assessment is based on invasive clinical measurements and cross-validation techniques with the Philips proprietary validated software's Qflow and 2D Perfursion...
2017: PeerJ
https://www.readbyqxmd.com/read/28121708/cerebral-blood-flow-and-cognitive-function-in-hiv-infected-men-with-sustained-suppressed-viremia-on-combination-antiretroviral-therapy
#19
Tanja Su, Henk-Jan Mutsaerts, Matthan W A Caan, Ferdinand W N M Wit, Judith Schouten, Gert J Geurtsen, David J Sharp, Maria Prins, E Richard, Peter Portegies, Peter Reiss, Charles B Majoie
OBJECTIVE: To assess if HIV-infected patients on long-term successful combination antiretroviral therapy (cART) show cerebral blood flow (CBF) alterations in comparison to HIV-uninfected, otherwise similar controls. To explore whether such alterations are associated with HIV-associated cognitive impairment and to explore potential determinants of CBF alterations in HIV. DESIGN: Cross-sectional comparison of CBF in an observational cohort study. METHODS: Clinical, cognitive and magnetic resonance imaging (MRI) data of 100 middle-aged aviremic HIV-infected men on cART and 69 HIV-uninfected controls were collected and compared...
January 24, 2017: AIDS
https://www.readbyqxmd.com/read/28120178/journal-of-clinical-monitoring-and-computing-2016-end-of-year-summary-monitoring-cerebral-oxygenation-and-autoregulation
#20
REVIEW
Thomas W L Scheeren, Bernd Saugel
In the perioperative and critical care setting, monitoring of cerebral oxygenation (ScO2) and cerebral autoregulation enjoy increasing popularity in recent years, particularly in patients undergoing cardiac surgery. Monitoring ScO2 is based on near infrared spectroscopy, and attempts to early detect cerebral hypoperfusion and thereby prevent cerebral dysfunction and postoperative neurologic complications. Autoregulation of cerebral blood flow provides a steady flow of blood towards the brain despite variations in mean arterial blood pressure (MAP) and cerebral perfusion pressure, and is effective in a MAP range between approximately 50-150 mmHg...
January 24, 2017: Journal of Clinical Monitoring and Computing
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