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cerebral blood flow velocity

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https://www.readbyqxmd.com/read/27911329/comparison-of-model-based-indices-of%C3%A2-cerebral-autoregulation-and-vasomotor-reactivity-using-transcranial-doppler-versus-near-infrared-spectroscopy-in%C3%A2-patients-with-amnestic-mild-cognitive-impairment
#1
Vasilis Z Marmarelis, Dae C Shin, Takashi Tarumi, Rong Zhang
We recently introduced model-based "physiomarkers" of dynamic cerebral autoregulation and CO2 vasomotor reactivity as an aid for diagnosis of early-stage Alzheimer's disease (AD) [1], where significant impairment of dynamic vasomotor reactivity (DVR) was observed in early-stage AD patients relative to age-matched controls. Milder impairment of DVR was shown in patients with amnestic mild cognitive impairment (MCI) using the same approach in a subsequent study [2]. The advocated approach utilizes subject-specific data-based models of cerebral hemodynamics to quantify the dynamic effects of resting-state changes in arterial blood pressure and end-tidal CO2 (the putative inputs) upon cerebral blood flow velocity (the putative output) measured at the middle cerebral artery via transcranial Doppler (TCD)...
November 28, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27909604/effects-of-head-position-on-cerebral-oxygenation-and-blood-flow-velocity-during-thyroidectomy
#2
Ayten Saraçoğlu, Demet Altun, Ayşen Yavru, Nihat Aksakal, İsmail Cem Sormaz, Emre Camcı
OBJECTIVE: Determining the blood flow through intra and extra-cranial arteries during neck extension may be helpful but is a controversial issue. We aimed to elucidate the changes in cerebral blood flow related to head positioning during thyroid surgery by carotid Doppler examination and regional oxygen saturation variations. METHODS: Thirty patients were recruited to the study. Patients were positioned with a final position of thyroidectomy consisting a 30° semi Fowler with the extension of neck and head...
October 2016: Turkish Journal of Anaesthesiology and Reanimation
https://www.readbyqxmd.com/read/27880813/transcranial-doppler-based-surrogates-for-cerebral-blood-flow-a-statistical-study
#3
Joseph Hart, Vera Novak, Charles Saunders, Pierre A Gremaud
It is commonly assumed that perfusion in a given cerebral territory can be inferred from Blood Flow Velocity (BFV) measurements in the corresponding stem artery. In order to test this hypothesis, we construct a cerebral blood flow (CBF) estimator based on transcranial Doppler (TCD) blood flow velocity and ten other easily available patient characteristics and clinical parameters. A total of 261 measurements were collected from 88 older patients. The estimator is based on local regression (Random Forest). Its performance is analyzed against baseline CBF from 3-D pseudocontinuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI)...
2016: PloS One
https://www.readbyqxmd.com/read/27862767/dynamics-of-cerebral-blood-flow-in-patients-with-mild-non-ischaemic-heart-failure
#4
Christian D Erkelens, Haye H van der Wal, Bauke M de Jong, Jan-Willem Elting, Remco Renken, Marleen Gerritsen, Peter Jan van Laar, Vincent M van Deursen, Peter van der Meer, Dirk J van Veldhuisen, Adriaan A Voors, Gert-Jan Luijckx
AIMS: Heart failure (HF) is associated with tissue hypoperfusion and congestion leading to organ dysfunction. Although cerebral blood flow (CBF) is preserved over a wide range of perfusion pressures in healthy subjects, it is impaired in end-stage HF. We aimed to compare CBF, autoregulation, and cognitive function in patients with mild non-ischaemic HF with healthy controls. METHODS AND RESULTS: Fifteen patients with mild idiopathic dilated cardiomyopathy and 15 matched healthy controls were studied...
November 14, 2016: European Journal of Heart Failure
https://www.readbyqxmd.com/read/27861273/thermodilution-determined-internal-jugular-venous-flow
#5
Peter Rasmussen, Mario Widmer, Matthias P Hilty, Mike Hug, Henrik Sørensen, Shigehiko Ogoh, Kohei Sato, Niels H Secher, Marco Maggiorini, Carsten Lundby
PURPOSE: Cerebral blood flow (CBF) increases ~20% during whole body exercise although a Kety-Schmidt-determined CBF is reported to remain stable; a discrepancy that could reflect evaluation of arterial vs. internal jugular venous (IJV) flow and/or that CBF is influenced by posture. Here we test the hypothesis that IJV flow, as determined by retrograde thermodilution increases during exercise when body position is maintained. METHODS: Introducing retrograde thermodilution, IJV flow was measured in 8 healthy humans at supine and upright rest and during exercise in normoxia and hypoxia with results compared to changes in ultrasound-derived IJV flow and middle cerebral artery mean velocity (MCA Vmean)...
November 17, 2016: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/27850373/735-cerebral-blood-flow-velocity-and-autoregulation-in-children-after-a-global-hypoxic-ischemic-event
#6
Marlina Lovett, Melissa Chung, Tensing Maa, Nicole O'Brien
No abstract text is available yet for this article.
December 2016: Critical Care Medicine
https://www.readbyqxmd.com/read/27837190/hyperoxia-results-in-increased-aerobic-metabolism-following-acute-brain-injury
#7
Arnab Ghosh, David Highton, Christina Kolyva, Ilias Tachtsidis, Clare E Elwell, Martin Smith
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24-72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy...
November 11, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27837172/comments-on-longitudinal-changes-in-cerebral-blood-flow-velocities-in-different-clinical-courses-of-migraine-by-lee-et%C3%A2-al
#8
EDITORIAL
Ole Hensel
No abstract text is available yet for this article.
November 10, 2016: Cephalalgia: An International Journal of Headache
https://www.readbyqxmd.com/read/27830942/postural-asymmetry-correlated-with-lateralization-of-cerebellar-perfusion-in-persons-with-chronic-stroke-a-role-of-crossed-cerebellar-diaschisis-in-left-side
#9
Cheng-Chiang Chang, Chih-Hung Ku, Shin-Tsu Chang
OBJECTIVE: Hemiplegia after stroke leads to impairment of the affected limbs and induces more weight on the non-paretic lower limb to form postural asymmetry. Studies of asymmetric cerebral functions have found similarly asymmetric functions in the cerebellum. Crossed cerebellar diaschisis (CCD) is defined as reduced blood flow and hypometabolism in the cerebellar hemisphere contralateral to supratentorial cerebral pathology. No study explored the relationship between posture (standing balance) and CCD in those persons yet...
November 10, 2016: Brain Injury: [BI]
https://www.readbyqxmd.com/read/27810458/effect-of-hyperoxia-on-cerebral-blood-flow-velocity-and-regional-oxygen-saturation-in-patients-operated-upon-for-severe-traumatic-brain-injury-the-influence-of-cerebral-blood-flow-autoregulation
#10
Sarasa Sahoo, Veena Sheshadri, Kamath Sriganesh, K R Madhsudana Reddy, M Radhakrishnan, G S Umamaheswara Rao
BACKGROUND: The effect of normobaric hyperoxia on brain oxygenation in the presence or absence of intact autoregulation has not been studied till now in acute traumatic brain injury (TBI). METHODS: In this prospective clinical investigation in fifty patients operated for severe TBI, cerebral blood flow (CBF) velocity in the middle cerebral artery (MCA) was measured using transcranial doppler (TCD). Regional cerebral oxygen saturation (rSO2) using near infra-red spectroscopy (NIRS) at three different inspired oxygen fractions (FiO2 of 0...
October 31, 2016: World Neurosurgery
https://www.readbyqxmd.com/read/27789785/distribution-of-cardiac-output-to-the-brain-across-the-adult-lifespan
#11
Chang-Yang Xing, Takashi Tarumi, Jie Liu, Yinan Zhang, Marcel Turner, Jonathan Riley, Cynthia Duron Tinajero, Li-Jun Yuan, Rong Zhang
A widely accepted dogma is that about 15-20% of cardiac output is received by the brain in healthy adults under resting conditions. However, it is unclear if the distribution of cardiac output directed to the brain alters across the adult lifespan and is modulated by sex or other hemodynamic variables. We measured cerebral blood flow/cardiac output ratio index in 139 subjects (88 women, age 21-80 years) using phase-contrast magnetic resonance imaging and echocardiography. Body mass index, cardiac systolic function (eject fraction), central arterial stiffness (carotid-femoral pulse wave velocity), arterial pressure, heart rate, physical fitness (VO2 max), and total brain volume were measured to assess their effects on the cardiac output-cerebral blood flow relationship...
October 27, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27757739/cerebral-hemodynamics-in-sepsis-assessed-by-transcranial-doppler-a-systematic-review-and-meta-analysis
#12
Daniel Silva de Azevedo, Angela Salomao Macedo Salinet, Marcelo de Lima Oliveira, Manoel Jacobsen Teixeira, Edson Bor-Seng-Shu, Ricardo de Carvalho Nogueira
Cerebral microcirculation is gradually compromised during sepsis, with significant reductions in the function of capillaries and blood perfusion in small vessels. Transcranial Doppler ultrasound (TCD) has been used to assess cerebral circulation in a typical clinical setting. This study was to systematically review TCD studies, assess their methodological quality, and identify trends that can be associated with the temporal evolution of sepsis and its clinical outcome. A meta-analysis of systematic reviews was conducted according to the PRISMA statement...
October 18, 2016: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/27754285/me-04-3-epidemiology-and-consequences-of-early-vascular-aging
#13
Junichiro Hashimoto
Arterial structure and function change progressively with advancing age. Owing to long-lasting repetitive stretch with intermittent cardiac contraction, elastic fibers in the tunica media of large arteries gradually degenerate and are replaced by collagenous fibers. Such medial degeneration causes elastic arteries to stiffen and dilate. However, the speed of the vascular aging varies considerably among individuals; a discrepancy often exists between the chronological age of an individual and the biological age of his or her arteries...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27743745/use-of-transcranial-doppler-for-management-of-central-nervous-system-infections-in-critically-ill-children
#14
Laurence Ducharme-Crevier, Michele G Mills, Priya M Mehta, Craig M Smith, Mark S Wainwright
BACKGROUND: The primary objective of this study was to characterize changes in cerebral blood flow measured using transcranial Doppler in children with central nervous system infections. We hypothesized that children with central nervous system infections have abnormal cerebral blood flow, associated with a greater frequency of complications and poor neurological outcome. METHODS: We conducted a single-center, retrospective study of children admitted to the neonatal or pediatric intensive care unit with central nervous system infection and undergoing transcranial Doppler as part of routine care between March 2011 and July 2015...
December 2016: Pediatric Neurology
https://www.readbyqxmd.com/read/27702883/internal-carotid-artery-blood-flow-in-healthy-awake-subjects-is-reduced-by-simulated-hypovolemia-and-noninvasive-mechanical-ventilation
#15
Maria Skytioti, Signe Søvik, Maja Elstad
Intact cerebral blood flow (CBF) is essential for cerebral metabolism and function, whereas hypoperfusion in relation to hypovolemia and hypocapnia can lead to severe cerebral damage. This study was designed to assess internal carotid artery blood flow (ICA-BF) during simulated hypovolemia and noninvasive positive pressure ventilation (PPV) in young healthy humans. Beat-by-beat blood velocity (ICA and aorta) were measured by Doppler ultrasound during normovolemia and simulated hypovolemia (lower body negative pressure), with or without PPV in 15 awake subjects...
October 2016: Physiological Reports
https://www.readbyqxmd.com/read/27689154/the-posterior-cerebral-artery-and-its-main-cortical-branches-identified-with-noninvasive-transcranial-color-coded-duplex-sonography
#16
P E Frid, S J Schreiber, O Pade, F Doepp, J Valdueza
PURPOSE: To differentiate PCA segments and cortical branches by means of transcranial color-coded duplex sonography (TCCD) and to measure flow parameters at rest and during visual stimulation. MATERIALS AND METHODS: 60 healthy subjects with a good acoustic temporal bone window were examined. The main stem of the PCA (P1, P2 and P3) and 4 main cortical branches - the anterior temporal artery (ATA), the occipital temporal artery (OTA), the parietooccipital artery (POA) and the calcarine artery (CA) - were assessed using an axial transtemporal approach...
November 2015: Ultrasound International Open
https://www.readbyqxmd.com/read/27665361/difference-in-transcranial-doppler-velocity-and-patient-age-between-proximal-and-distal-middle-cerebral-artery-vasospasms-after-aneurysmal-subarachnoid-hemorrhage
#17
Misaki Kohama, Shinichiro Sugiyama, Kenichi Sato, Hidenori Endo, Kuniyasu Niizuma, Toshiki Endo, Makoto Ohta, Yasushi Matsumoto, Miki Fujimura, Teiji Tominaga
BACKGROUND: Transcranial Doppler (TCD) is used to monitor cerebral vasospasm after subarachnoid hemorrhage (SAH), but its diagnostic ability is reported to be limited. Therefore, the purpose of this study was to investigate the relationship between the diagnosability of TCD and the localization of the vasospasm. METHODS: This retrospective study included 20 patients who presented with symptomatic vasospasm after SAH. All 20 patients underwent daily TCD examinations and cerebral angiography after the onset of delayed cerebral ischemia...
2016: Cerebrovascular Diseases Extra
https://www.readbyqxmd.com/read/27648976/determinants-of-cerebral-hemodynamics-during-the-trail-making-test-in-schizophrenia
#18
Daniel Schuepbach, Stephan T Egger, Heinz Boeker, Stefan Duschek, Stefan Vetter, Erich Seifritz, Sabine C Herpertz
Patients with schizophrenia show deficits in cognitive functioning, and studies on cerebral hemodynamics have revealed aberrant patterns of mean cerebral blood flow velocity (MFV), an equivalent of cerebral blood flow (CBF). Therefore, we carried out a controlled study that assessed MFV in schizophrenia during a well-known neuropsychological task, the Trail Making Test (TMT). We measured MFV in the middle cerebral arteries using functional transcranial Doppler sonography in 15 schizophrenia patients and 15 healthy subjects...
September 17, 2016: Brain and Cognition
https://www.readbyqxmd.com/read/27644162/effects-of-continuous-positive-airway-pressure-and-isocapnic-hypoxia-on-cerebral-autoregulation-in-patients-with-obstructive-sleep-apnoea
#19
Xavier Waltz, Andrew E Beaudin, Patrick J Hanly, Georgios D Mitsis, Marc J Poulin
KEY POINTS: Altered cerebral autoregulation (CA) in obstructive sleep apnoea (OSA) patients may contribute to increased stroke risk in this population; the gold standard treatment for OSA is continuous positive airway pressure, which improves cerebrovascular regulation and may decrease the risk of stroke. Isocapnic-hypoxia impairs CA in healthy subjects, but it remains unknown in OSA whether impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment with continuous positive airway pressure...
December 1, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27643283/me-04-3-epidemiology-and-consequences-of-early-vascular-aging
#20
Junichiro Hashimoto
Arterial structure and function change progressively with advancing age. Owing to long-lasting repetitive stretch with intermittent cardiac contraction, elastic fibers in the tunica media of large arteries gradually degenerate and are replaced by collagenous fibers. Such medial degeneration causes elastic arteries to stiffen and dilate. However, the speed of the vascular aging varies considerably among individuals; a discrepancy often exists between the chronological age of an individual and the biological age of his or her arteries...
September 2016: Journal of Hypertension
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