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cerebral blood flow velocity

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https://www.readbyqxmd.com/read/28057635/in-vivo-assessment-of-the-impact-of-regional-intracranial-atherosclerotic-lesions-on-brain-arterial-3d-hemodynamics
#1
C Wu, S Schnell, P Vakil, A R Honarmand, S A Ansari, J Carr, M Markl, S Prabhakaran
BACKGROUND AND PURPOSE: Intracranial atherosclerosis induces hemodynamic disturbance, which is not well-characterized, particularly in cerebral flow redistribution. We aimed to characterize the impact of regional stenotic lesions on intracranial hemodynamics by using 4D flow MR imaging. MATERIALS AND METHODS: 4D flow MR imaging was performed in 22 symptomatic patients (mean age, 68.4 ± 14.2 years) with intracranial stenosis (ICA, n = 7; MCA, n = 9; basilar artery, n = 6) and 10 age-appropriate healthy volunteers (mean age, 60...
January 5, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28054939/effects-of-resveratrol-on-cognitive-performance-mood-and-cerebrovascular-function-in-post-menopausal-women-a-14-week-randomised-placebo-controlled-intervention-trial
#2
Hamish M Evans, Peter R C Howe, Rachel H X Wong
We tested whether chronic supplementation with resveratrol (a phytoestrogen) could improve cerebrovascular function, cognition and mood in post-menopausal women. Eighty post-menopausal women aged 45-85 years were randomised to take trans-resveratrol or placebo for 14 weeks and the effects on cognitive performance, cerebral blood flow velocity and pulsatility index (a measure of arterial stiffness) in the middle cerebral artery (using transcranial Doppler ultrasound), and cerebrovascular responsiveness (CVR) to both cognitive testing and hypercapnia were assessed...
January 3, 2017: Nutrients
https://www.readbyqxmd.com/read/28052565/cerebral-hemodynamics-and-pseudo-continuous-arterial-spin-labeling-considerations-in-adults-with-sickle-cell-anemia
#3
Meher R Juttukonda, Lori C Jordan, Melissa C Gindville, Larry T Davis, Jennifer M Watchmaker, Sumit Pruthi, Manus J Donahue
Sickle cell anemia (SCA) is a genetic disorder resulting in reduced oxygen carrying capacity and elevated stroke risk. Pseudo-continuous arterial spin labeling (pCASL) measures of cerebral blood flow (CBF) may have relevance for stroke risk assessment; however, the effects of elevated flow velocity and reduced bolus arrival time (BAT) on CBF quantification in SCA patients have not been thoroughly characterized, and pCASL model parameters used in healthy adults are often applied to patients with SCA. Here, cervical arterial flow velocities and pCASL labeling efficiencies were computed in adults with SCA (n = 19) and age- and race-matched controls without sickle trait (n = 7) using pCASL in sequence with phase contrast MR angiography (MRA)...
January 4, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28049202/aortic-atherosclerosis-determines-increased-retrograde-blood-flow-as-a-potential-mechanism-of-retrograde-embolic-stroke
#4
Thomas Wehrum, Felix Guenther, Werner Vach, Beryl Primrose Gladstone, Sarah Wendel, Alexander Fuchs, Kehzong Wu, Christoph Johannes Maurer, Andreas Harloff
BACKGROUND: Retrograde brain embolization from complex plaques of the proximal descending aorta (DAo) has been identified as a new potential mechanism of stroke. Our purpose was to identify predictors of increased retrograde aortic blood flow indicating an elevated risk of brain embolization from the DAo. METHODS: A total of 485 patients with acute ischemic stroke were prospectively included and underwent transesophageal echocardiography. Blood flow velocities in the proximal DAo were studied using 2D pulse-wave Doppler ultrasound...
January 4, 2017: Cerebrovascular Diseases
https://www.readbyqxmd.com/read/28039210/relationship-between-tissue-doppler-measurements-of-left-ventricular-diastolic-function-and-silent-brain-infarction-in-patients-with-non-valvular-atrial-fibrillation
#5
Sera Ishikawa, Kenichi Sugioka, Shinichi Sakamoto, Suwako Fujita, Asahiro Ito, Naoki Norioka, Shinichi Iwata, Masashi Nakagawa, Masahiko Takagi, Yukio Miki, Makiko Ueda, Minoru Yoshiyama
AIMS: Left ventricular (LV) diastolic function assessed by tissue Doppler imaging (TDI) is reported to be associated with left atrial (LA) blood stasis in patients with non-valvular atrial fibrillation (AF). This study aimed to evaluate the relationship of diastolic TDI parameters with silent brain infarction (SBI) on brain magnetic resonance imaging (MRI), and in turn the risks of subsequent stroke or dementia, in non-valvular AF patients. METHODS AND RESULTS: The study population consisted of 171 neurologically asymptomatic patients with non-valvular AF who underwent transoesophageal echocardiography (TOE) (128 men; mean age, 63 ± 11 years)...
December 29, 2016: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28038898/demographic-and-systemic-hemodynamic-influences-in-mechanisms-of-cerebrovascular-regulation-in-healthy-adults
#6
João Madureira, Pedro Castro, Elsa Azevedo
OBJECTIVES: A competent cerebrovascular regulation maintains an adequate cerebral blood flow by 3 major mechanisms: cerebral autoregulation (CA), vasomotor reactivity (VMR), namely to CO2, and neurovascular coupling (NVC). However, most studies generalize their results based on a response to a single parameter. Using a full battery of neurovascular stress tests, our study aims to evaluate the relationships among grades of CA, VMR, and NVC, and how their interplay is influenced by demographic and systemic hemodynamic factors...
December 27, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28025360/patterns-of-cerebral-blood-flow-modulation-during-painful-stimulation-in-fibromyalgia-a-transcranial-doppler-sonography-study
#7
Casandra I Montoro, Stefan Duschek, Cristina Muñóz Ladrón de Guevara, Gustavo A Reyes Del Paso
OBJECTIVE: This study analyzed the temporal dynamics of cerebral blood flow (CBF) modulations, during painful stimulation in fibromyalgia syndrome (FMS), using functional transcranial Doppler sonography. METHOD: Blood flow velocities were recorded bilaterally in the anterior (ACA) and middle (MCA) cerebral arteries of 24 FMS patients and 20 healthy individuals during exposure to painful pressure stimulation. Participants were presented with two stimulation blocks: a) fixed pressure (2...
December 2016: Pain Medicine: the Official Journal of the American Academy of Pain Medicine
https://www.readbyqxmd.com/read/28024912/early-diagnosis-and-outcome-prediction-of-neonatal-hypoxic-ischemic-encephalopathy-with-color-doppler-ultrasound
#8
B Guan, C Dai, Y Zhang, L Zhu, X He, N Wang, H Liu
PURPOSE: To describe the ultrasound presentation of the brain and cerebral hemodynamics in neonates with hypoxic-ischemic encephalopathy (HIE) by comparison with control subjects. MATERIAL AND METHODS: During June 2012 to April 2013, full term neonates who had clinical evidence of HIE were enrolled. Healthy newborns without HIE were used as a control group. Cerebral parenchyma, size of lateral ventricles and hemodynamic parameters of cerebral arteries were studied using two-dimensional duplex and color Doppler ultrasound...
December 23, 2016: Diagnostic and Interventional Imaging
https://www.readbyqxmd.com/read/28018711/cerebral-capillary-velocimetry-based-on-temporal-oct-speckle-contrast
#9
Woo June Choi, Yuandong Li, Wan Qin, Ruikang K Wang
We propose a new optical coherence tomography (OCT) based method to measure red blood cell (RBC) velocities of single capillaries in the cortex of rodent brain. This OCT capillary velocimetry exploits quantitative laser speckle contrast analysis to estimate speckle decorrelation rate from the measured temporal OCT speckle signals, which is related to microcirculatory flow velocity. We hypothesize that OCT signal due to sub-surface capillary flow can be treated as the speckle signal in the single scattering regime and thus its time scale of speckle fluctuations can be subjected to single scattering laser speckle contrast analysis to derive characteristic decorrelation time...
December 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/28017224/hemorrhagic-transformation-and-cerebral-edema-in-acute-ischemic-stroke-link-to-cerebral-autoregulation
#10
Pedro Castro, Elsa Azevedo, Jorge Serrador, Isabel Rocha, Farzaneh Sorond
BACKGROUND: Hemorrhagic transformation and cerebral edema are feared complications of acute ischemic stroke but mechanisms are poorly understood and reliable early markers are lacking. Early assessment of cerebrovascular hemodynamics may advance our knowledge in both areas. We examined the relationship between dynamic cerebral autoregulation (CA) in the early hours post ischemia, and the risk of developing hemorrhagic transformation and cerebral edema at 24h post stroke METHODS: We prospectively enrolled 46 patients from our center with acute ischemic stroke in the middle cerebral artery territory...
January 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28012450/exploring-sexual-dimorphism-in-placental-circulation-at-22-24-weeks-of-gestation-a-cross-sectional-observational-study
#11
Christian Widnes, Kari Flo, Ganesh Acharya
INTRODUCTION: Placental blood flow is closely associated with fetal growth and wellbeing. Recent studies suggest that there are differences in blood flow between male and female fetuses. We hypothesized that sexual dimorphism exists in fetal and placental blood flow at 22-24 weeks of gestation. METHODS: This was a prospective cross-sectional study of 520 healthy pregnant women. Blood flow velocities of the middle cerebral artery (MCA), umbilical artery (UA), umbilical vein (UV) and the uterine arteries (UtA) were measured using Doppler ultrasonography...
January 2017: Placenta
https://www.readbyqxmd.com/read/28007503/low-spontaneous-variability-in-cerebral-blood-flow-velocity-in-non-survivors-after-cardiac-arrest
#12
J M D van den Brule, E J Vinke, L M van Loon, J G van der Hoeven, C W E Hoedemaekers
OBJECTIVE: To investigate spontaneous variability in the time and frequency domain in mean flow velocity (MFV) and mean arterial pressure (MAP) in comatose patients after cardiac arrest, and determine possible differences between survivors and non-survivors. METHODS: A prospective observational study was performed at the ICU of a tertiary care university hospital in the Netherlands. We studied 11 comatose patients and 10 controls. MFV in the middle cerebral artery was measured with simultaneously recording of MAP...
December 19, 2016: Resuscitation
https://www.readbyqxmd.com/read/27988320/heterogeneous-increases-of-regional-cerebral-blood-flow-during-preterm-brain-development-preliminary-assessment-with-pseudo-continuous-arterial-spin-labeled-perfusion-mri
#13
Minhui Ouyang, Peiying Liu, Tina Jeon, Lina Chalak, Roy Heyne, Nancy K Rollins, Daniel J Licht, John A Detre, Timothy P L Roberts, Hanzhang Lu, Hao Huang
The human brain develops rapidly during 32-45 postmenstrual weeks (PMW), a critical stage characterized by dramatic increases of metabolic demand. The increasing metabolic demand can be inferred through measurements of regional cerebral blood flow (CBF), which might be coupled to regional metabolism in preterm brains. Arterial spin labeled (ASL) perfusion MRI is one of the few viable approaches for imaging regional CBF of preterm brains, but must be optimized for the extremely slow blood velocity unique in preterm brains...
December 14, 2016: NeuroImage
https://www.readbyqxmd.com/read/27978784/correlation-between-decreased-parasympathetic-activity-and-reduced-cerebrovascular-reactivity-in-patients-with-lacunar-infarct
#14
Kannakorn Intharakham, Kesorn Suwanprasert, Sombat Muengtaweepongsa
Reduced cerebrovascular reactivity (CVR) was found in patients with recent lacunar infarct. However, its mechanisms were controversial. The breath holding maneuver as vasodilatory stimulus is clinically useful for an estimation of cerebrovasomotor reactivity in well co-operative patients. Patients with lacunar infarct have no higher cortical dysfunction and remain well co-operation. The breath holding maneuver is feasible and safe to perform in patients with lacunar infarct. Autonomic nervous system regulates systemic vascular activity...
13, 2016: Current Neurovascular Research
https://www.readbyqxmd.com/read/27977514/neural-correlates-of-brain-state-in-chronic-ischemia-and-stroke-combined-resting-state-electroencephalogram-and-transcranial-doppler-ultrasonographic-study
#15
Olga V Martynova, Galina V Portnova, Ksenya V Gladun
Clinical neurology is constantly searching for reliable indices of ischemic brain damage to prevent a possible development of stroke. We suggest that resting state electroencephalogram (rsEEG) with respect to other clinical data may provide important information about the severity of ischemia. We carried out correlation analysis of rsEEG, data of transcranial Doppler ultrasonography of head vessels, and clinical assessment scores collected from healthy volunteers and four groups of patients with mild chronic microvascular ischemia (CMI-1), moderate CMI (CMI-2), severe atrophy of the cerebral hemisphere, ischemic stroke in the left middle cerebral artery stroke, and ischemic stroke in the right middle cerebral artery stroke...
December 13, 2016: Neuroreport
https://www.readbyqxmd.com/read/27957790/transcranial-doppler-in-hemoglobin-sc-disease
#16
Camilo Vieira, Carolina Nogueira Costa de Oliveira, Ludmila Araújo Borges de Figueiredo, Rayra Pereira Santiago, Corynne Stephanie Ahouefa Adanho, Sanzio Silva Santana, Caroline Lang Burak, Isa Menezes Lyra, Marilda Souza Goncalves
BACKGROUND: Stroke is a severe clinical disorder in sickle cell disease (SCD), and few studies have evaluated transcranial Doppler (TCD) flow velocities in hemoglobin SC disease (HbSC). The guidelines for stroke risk are based on evaluations in sickle cell anemia (SCA) or HbS/β thalassemia. PROCEDURE: In this study, we compare cerebral blood flow in patients with SCD stratified by genotypes. A total of 1,664 pediatric patients with SCD underwent TCD velocity screening, and the time-averaged maximum mean velocity (TAMM) was determined in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and distal intracranial internal carotid artery (ICA) ...
December 13, 2016: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/27956677/effects-of-pneumoperitoneum-and-trendelenburg-position-on-intracranial-pressure-assessed-using-different-non-invasive-methods
#17
C Robba, D Cardim, J Donnelly, A Bertuccio, S Bacigaluppi, N Bragazzi, B Cabella, X Liu, B Matta, M Lattuada, M Czosnyka
BACKGROUND: The laparoscopic approach is becoming increasingly frequent for many different surgical procedures. However, the combination of pneumoperitoneum and Trendelenburg positioning associated with this approach may increase the patient's risk for elevated intracranial pressure (ICP). Given that the gold standard for the measurement of ICP is invasive, little is known about the effect of these common procedures on ICP. METHODS: We prospectively studied 40 patients without any history of cerebral disease who were undergoing laparoscopic procedures...
December 2016: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/27942470/basal-ganglia-perfusion-using-dynamic-color-doppler-sonography-in-infants-with-hypoxic-ischemic-encephalopathy-receiving-therapeutic-hypothermia-a-pilot-study
#18
Ricardo Faingold, Guilherme Cassia, Linda Morneault, Christine Saint-Martin, Guilherme Sant'Anna
BACKGROUND: The objective of this study was to evaluate the cerebral perfusion of the basal ganglia in infants with hypoxic-ischemic encephalopathy (HIE) receiving hypothermia using dynamic color Doppler sonography (CDS) and investigate for any correlation between these measurements and survival. METHODS: Head ultrasound (HUS) was performed with a 9S4 MHz sector transducer in HIE infants submitted to hypothermia as part of their routine care. Measurements of cerebral perfusion intensity (CPI) with an 11LW4 MHz linear array transducer were performed to obtain static images and DICOM color Doppler videos of the blood flow in the basal ganglia area...
October 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/27939486/changes-in-cerebral-autoregulation-in-the-second-half-of-pregnancy-and-compared-to-non-pregnant-controls
#19
Teelkien R van Veen, Ronney B Panerai, Sina Haeri, Paul P van den Berg, Gerda G Zeeman, Michael A Belfort
OBJECTIVE: The mechanism by which pregnancy affects the cerebral circulation is unknown, but it has a central role in the development of neurological complications in preeclampsia, which is believed to be related to impaired autoregulation. We evaluated the cerebral autoregulation in the second half of pregnancy, and compared this with a control group of healthy, fertile non-pregnant women. METHODS: In a prospective cohort analysis, cerebral blood flow velocity of the middle cerebral artery (determined by transcranial Doppler), blood pressure (noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously collected for 7min...
October 2016: Pregnancy Hypertension
https://www.readbyqxmd.com/read/27932509/use-of-phase-contrast-mra-to-assess-intracranial-venous-sinus-resistance-to-drainage-in-healthy-individuals
#20
S Fall, G Pagé, J Bettoni, R Bouzerar, O Balédent
BACKGROUND AND PURPOSE: Resistance to blood flow in the cerebral drainage system may affect cerebral hemodynamics. The objective of the present study was to use phase-contrast MRA to quantify resistance to drainage of blood across branches of the venous sinus tree and to determine whether the resistance to drainage values correlated with internal jugular vein outflows. MATERIALS AND METHODS: We performed whole-head phase-contrast MRA and 2D phase-contrast MR imaging in 31 healthy volunteers...
December 8, 2016: AJNR. American Journal of Neuroradiology
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