keyword
MENU ▼
Read by QxMD icon Read
search

cerebral blood flow velocity

keyword
https://www.readbyqxmd.com/read/28720078/characteristics-of-cardio-cerebrovascular-modulation-in-patients-with-generalized-anxiety-disorder-an-observational-study
#1
Zhen-Ni Guo, Liangshu Feng, Xiuli Yan, Le Yang, Shuo Huang, Yingqi Xing, Yi Yang
BACKGROUND: Generalized anxiety disorder (GAD) has been shown in previous studies to display abnormal cerebral blood flow velocity (CBFV); however, the characteristics of cardio-cerebrovascular modulation are unknown. We aimed to analyze cardio-cerebrovascular modulation using parameters from a supine-to-standing test. METHODS: There are 2 parts to this study; in Part 1, 125 participants with Hamilton Anxiety scale scores ≥14 were enrolled, and 33 age- and sex-matched medically and psychiatrically healthy volunteers were recruited as control participants...
July 18, 2017: BMC Psychiatry
https://www.readbyqxmd.com/read/28700720/altered-cerebral-blood-flow-velocity-features-in-fibromyalgia-patients-in-resting-state-conditions
#2
Alejandro Rodríguez, José Tembl, Patricia Mesa-Gresa, Miguel Ángel Muñoz, Pedro Montoya, Beatriz Rey
The aim of this study is to characterize in resting-state conditions the cerebral blood flow velocity (CBFV) signals of fibromyalgia patients. The anterior and middle cerebral arteries of both hemispheres from 15 women with fibromyalgia and 15 healthy women were monitored using Transcranial Doppler (TCD) during a 5-minute eyes-closed resting period. Several signal processing methods based on time, information theory, frequency and time-frequency analyses were used in order to extract different features to characterize the CBFV signals in the different vessels...
2017: PloS One
https://www.readbyqxmd.com/read/28694108/increased-blood-pressure-variability-upon-standing-up-improves-reproducibility-of-cerebral-autoregulation-indices
#3
Adam Mahdi, Dragana Nikolic, Anthony A Birch, Mette S Olufsen, Ronney B Panerai, David M Simpson, Stephen J Payne
Dynamic cerebral autoregulation, that is the transient response of cerebral blood flow to changes in arterial blood pressure, is currently assessed using a variety of different time series methods and data collection protocols. In the continuing absence of a gold standard for the study of cerebral autoregulation it is unclear to what extent does the assessment depend on the choice of a computational method and protocol. We use continuous measurements of blood pressure and cerebral blood flow velocity in the middle cerebral artery from the cohorts of 18 normotensive subjects performing sit-to-stand manoeuvre...
July 7, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28694107/effects-of-non-physiological-blood-pressure-artefacts-on-cerebral-autoregulation
#4
Adam Mahdi, Erica M Rutter, Stephen J Payne
Cerebral autoregulation refers to the brain's regulation mechanisms that aim to maintain the cerebral blood flow approximately constant. It is often assessed by the autoregulation index (ARI). ARI uses arterial blood pressure and cerebral blood flow velocity time series to produce a ten-scale index of autoregulation performance (0 denoting the absence of and 9 the strongest autoregulation). Unfortunately, data are rarely free from various artefacts. Here, we consider four of the most common non-physiological blood pressure artefacts (saturation, square wave, reduced pulse pressure and impulse) and study their effects on ARI for a range of different artefact sizes...
July 7, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28692445/normal-cerebral-vascular-pulsations-in-humans-changes-with-age-and-implications-for-microvascular-disease
#5
Mi O Kim, Yan Li, Fangfei Wei, Jiguang Wang, Michael F O'Rourke, Audrey Adji, Alberto P Avolio
BACKGROUND: Cerebral syndromes in older humans, secondary stroke in younger persons following trauma, and sickle cell anaemia in children, are linked by unexplained microvascular damage and high cerebral pressure or flow pulsations. The aim of this study was to characterize age-related pressure and flow waveforms patterns entering the brain, to explain these in terms of disturbed physiological function, and to consider clinical implications. METHOD: Blood flow velocity waves were measured in four cerebral vascular territories by transcranial Doppler of 1020 apparently normal patients (497 men, 21-78 years)...
July 7, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28686073/effect-of-hypoxia-on-bold-fmri-response-and-total-cerebral-blood-flow-in-migraine-with-aura-patients
#6
Nanna Arngrim, Anders Hougaard, Henrik W Schytz, Mark B Vestergaard, Josefine Britze, Faisal Mohammad Amin, Karsten S Olsen, Henrik Bw Larsson, Jes Olesen, Messoud Ashina
Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28681121/indexes-of-cerebral-autoregulation-do-not-reflect-impairment-in-syncope-insights-from-head-up-tilt-test-of-vasovagal-and-autonomic-failure-subjects
#7
Pedro Castro, João Freitas, Rosa Santos, Ronney Panerai, Elsa Azevedo
PURPOSE: The study of dynamic cerebral autoregulation (CA), which adapts cerebral blood flow to arterial blood pressure (ABP) fluctuations, has been limited in orthostatic intolerance syndromes, mainly due to its stationary prerequisites hardly to meet during maneuvers to provoke syncope itself. New techniques of continuous estimates of CA could overcome this pitfall. We aimed to evaluate CA during head-up tilt test in common conditions causing syncope. METHODS: We compared three groups: eight controls; eight patients with autonomic failure due to familial amyloidotic polyneuropathy; eight patients with vasovagal syncope (VVS)...
July 5, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28680306/changes-in-cerebral-blood-flow-in-patients-with-familial-mediterranean-fever
#8
Gözde Çetin, Uygar Utku, Nurhan Atilla, Kadir Gişi, Mehmet Sayarlioğlu
INTRODUCTION: It is known that there is a relationship between systemic inflammation and atherosclerosis. Atherosclerosis is one of the best-known causes of cerebrovascular diseases. The aim of this study was to assess cerebral blood flow velocity using transcranial Doppler (TCD) ultrasonography in patients with familial Mediterranean fever (FMF). METHODS: A total of 30 patients aged from 20 to 50 years with FMF were enrolled in the FMF group consecutively. The control group (non-FMF group) consisted of 30 age- and sex-matched randomly selected patients without FMF who had other diagnoses such as fibromyalgia and did not have risk factors for atherosclerosis...
June 2017: Noro Psikiyatri Arsivi
https://www.readbyqxmd.com/read/28678308/evaluation-function-of-transcranial-two-dimensional-and-color-doppler-ultrasonography-tccs-for-patients-with-different-degrees-of-cerebral-vasospasm-before-and-after-the-nimodipine-treatment
#9
J-L Wang, X-N Li, Y-H Zhang, X Li, Y-L Yang
OBJECTIVE: To evaluate the changes in cerebral hemodynamics of patients with different degrees of cerebral vasospasm before and after the nimodipine treatment using transcranial two-dimensional and color Doppler ultrasonography (TCCS). PATIENTS AND METHODS: A total of 77 patients with subarachnoid hemorrhage was collected; and the maximum peak systolic velocity (Vs), end diastolic velocity (Vd), time averaged maximum velocity (Vm), pulsatility index (PI) and resistance index (RI) of middle cerebral artery (MCA) were measured by spectral Doppler technique...
June 2017: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/28671118/cerebral-hemodynamics-in-mild-cognitive-impairment-a-systematic-review
#10
Lucy Beishon, Victoria J Haunton, Ronney B Panerai, Thompson G Robinson
BACKGROUND: The incidence of dementia is projected to rise over the coming decades, but with no sensitive diagnostic tests available. Vascular pathology precedes the deposition of amyloid and is an attractive early target. OBJECTIVE: The aim of this review was to investigate the use of cerebral hemodynamics and oxygenation as a novel biomarker for mild cognitive impairment (MCI), focusing on transcranial Doppler ultrasonography (TCD) and near-infrared spectroscopy (NIRS)...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28666000/dynamic-wheelchair-seating-positions-impact-cardiovascular-function-after-spinal-cord-injury
#11
Jessica A Inskip, Henrike Rianne J C Ravensbergen, Inderjeet S Sahota, Christine Zawadzki, Lowell T McPhail, Jaimie F Borisoff, Victoria E Claydon
BACKGROUND: Innovative wheelchairs allow individuals to change position easily for comfort and social situations. While these wheelchairs are beneficial in multiple ways, the effects of position changes on blood pressure might exacerbate hypotension and cerebral hypoperfusion, particularly in those with spinal cord injury (SCI) who can have injury to autonomic nerves that regulate cardiovascular control. Conversely, cardiovascular benefits may be obtained with lowered seating. Here we investigate the effect of moderate changes in wheelchair position on orthostatic cardiovascular and cerebrovascular reflex control...
2017: PloS One
https://www.readbyqxmd.com/read/28664392/validation-of-near-infrared-spectroscopy-for-monitoring-cerebral-autoregulation-in-comatose-patients
#12
Lucia Rivera-Lara, Romergryko Geocadin, Andres Zorrilla-Vaca, Ryan Healy, Batya R Radzik, Caitlin Palmisano, Marek Mirski, Wendy C Ziai, Charles Hogue
BACKGROUND: Transcranial Doppler (TCD) noninvasively measures cerebral blood flow (CBF) velocity and is a well-studied method to monitor cerebral autoregulation (CA). Near-infrared spectroscopy (NIRS) has emerged as a promising noninvasive method to determine CA continuously by using regional cerebral oxygen saturation (rSO2) as a surrogate for CBF. Little is known about its accuracy to determine CA in patients with intracranial lesions. The purpose of this study was to assess the accuracy of rSO2-based CA monitoring with TCD methods in comatose patients with acute neurological injury...
June 29, 2017: Neurocritical Care
https://www.readbyqxmd.com/read/28663374/extra-and-intra-cranial-blood-flow-regulation-during-the-cold-pressor-test-influence-of-age
#13
Daniela Flück, Philip N Ainslie, Anthony R Bain, Kevin W Wildfong, Laura Emily Morris, James P Fisher
We determined how the extra- and intra-cranial circulations respond to generalized sympathetic activation evoked by a cold pressor test (CPT) and whether this was affected by healthy aging. Ten young (23±2 yr; mean±SD) and nine older (66±3 yr) individuals performed a 3-min CPT by immersing the left foot into 0.8±0.3°C water. Common carotid artery (CCA) and internal carotid artery (ICA) diameter, velocity and flow were simultaneously measured (duplex ultrasound), along with middle cerebral artery and posterior cerebral artery mean blood velocity (MCAvmean and PCAvmean), and cardiorespiratory variables...
June 29, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28656716/the-effects-of-chronic-smoking-on-total-cerebral-blood-volume-measured-by-carotid-and-vertebral-artery-doppler-ultrasonography
#14
Melike E Kalfaoglu, Mustafa Hızal, Aysu Kiyan, Kamil Gurel
PURPOSE: To evaluate the effects of chronic cigarette smoking on total cerebral blood flow in healthy adults by Doppler ultrasonography (US). METHODS: We evaluated 50 smoker (median age 29) and 50 nonsmoker (median age 28) healthy, 20- to 40-year-old subjects without any cardiovascular and cerebrovascular disease. Peak systolic maximal blood flow velocity (PSV), end-diastolic maximal blood flow velocity (EDV), time-averaged mean blood flow velocity (TAMV), resistance index (RI), and pulsatility index (PI) were measured in the left and right carotid and vertebral arteries, and total cerebral blood flow volume was calculated...
June 27, 2017: Journal of Clinical Ultrasound: JCU
https://www.readbyqxmd.com/read/28654638/increased-inspiratory-resistance-affects-the-dynamic-relationship-between-blood-pressure-changes-and-subarachnoid-space-width-oscillations
#15
Magdalena Wszedybyl-Winklewska, Jacek Wolf, Ewa Swierblewska, Katarzyna Kunicka, Kamila Mazur, Marcin Gruszecki, Pawel J Winklewski, Andrzej F Frydrychowski, Leszek Bieniaszewski, Krzysztof Narkiewicz
BACKGROUND AND OBJECTIVE: Respiration is known to affect cerebrospinal fluid (CSF) movement. We hypothesised that increased inspiratory resistance would affect the dynamic relationship between blood pressure (BP) changes and subarachnoid space width (SAS) oscillations. METHODS: Experiments were performed in a group of 20 healthy volunteers undergoing controlled intermittent Mueller Manoeuvres (the key characteristic of the procedure is that a studied person is subjected to a controlled, increased inspiratory resistance which results in marked potentiation of the intrathoracic negative pressure)...
2017: PloS One
https://www.readbyqxmd.com/read/28648719/modification-to-the-rice-vannucci-perinatal-hypoxic-ischaemic-encephalopathy-model-in-the-p7-rat-improves-the-reliability-of-cerebral-infarct-development-after-48hours
#16
Adam B Edwards, Kirk W Feindel, Jane L Cross, Ryan S Anderton, Vincent W Clark, Neville W Knuckey, Bruno P Meloni
BACKGROUND: The Rice-Vannucci model of hypoxic-ischaemic encephalopathy (HIE) has been associated with a high degree of variability with respect to the development of cerebral infarction and infarct lesion volume. For this reason, we examined the occurrence of communicational blood flow within the common carotid (CCA), internal (ICA), and external (ECA) carotid arteries following CCA occlusion as a source of variability in the model. NEW METHOD: We propose a novel modification to the Rice-Vannucci model, whereby both the CCA and ECA are permanently ligated; mitigating communicational blood flow...
June 23, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28642293/random-squat-stand-maneuvers-a-novel-approach-for-assessment-of-dynamic-cerebral-autoregulation
#17
Sam C Barnes, Naomi Ball, Victoria Joanna Haunton, Ronney B Panerai, Thompson G Robinson
BACKGROUND: Squat-stand maneuvers (SSM) have been used to assess dynamic cerebral autoregulation (dCA), but always at a fixed-frequency (FF). This study aimed to assess the use of random-frequency (RF) SSMs as a stimulus for measuring dCA, and to determine the reproducibility of FF and RFSSMs. METHOD: 29 healthy volunteers (19 male, mean age 23.0 [4.9] years) completed the study; 11 returned for a repeat visit (median 45 days). Heart rate, beat-to-beat blood pressure, middle cerebral artery (MCA) blood flow velocity, end-tidal CO2 and angle of the squat movement were measured...
June 22, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28627999/heritability-and-genome-wide-associations-studies-of-cerebral-blood-flow-in-the-general-population
#18
M Arfan Ikram, Hazel I Zonneveld, Gennady Roshchupkin, Albert V Smith, Oscar H Franco, Sigurdur Sigurdsson, Cornelia van Duijn, André G Uitterlinden, Lenore J Launer, Meike W Vernooij, Vilmundur Gudnason, Hieab Hh Adams
Cerebral blood flow is an important process for brain functioning and its dysregulation is implicated in multiple neurological disorders. While environmental risk factors have been identified, it remains unclear to what extent the flow is regulated by genetics. Here we performed heritability and genome-wide association analyses of cerebral blood flow in a population-based cohort study. We included 4472 persons free of cortical infarcts who underwent genotyping and phase-contrast magnetic resonance flow imaging (mean age 64...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28627298/a-prospective-transcranial-doppler-ultrasound-based-evaluation-of-the-acute-and-cumulative-effects-of-sport-related-concussion-on-neurovascular-coupling-response-dynamics
#19
Alexander D Wright, Jonathan D Smirl, Kelsey Bryk, Paul van Donkelaar
Sport-related concussion has been shown to alter cerebral blood flow (CBF) both acutely and chronically, and may exert cumulative effects across multiple injuries. Such dysfunction may be mediated by trauma-induced deficits to CBF control mechanisms, though our understanding of these effects is limited, including dynamics of neurovascular coupling (NVC) responses (i.e. CBF responses to neurologic demand). 179 junior-level contact sport athletes completed preseason testing - 42 reported never having experienced a concussion (Hx-) while 31 had endured three or more (Hx3+)...
June 18, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/28618187/physically-consistent-data-assimilation-method-based-on-feedback-control-for-patient-specific-blood-flow-analysis
#20
Satoshi Ii, Mohd Azrul Hisham Mohd Adib, Yoshiyuki Watanabe, Shigeo Wada
This paper presents a novel data assimilation method for patient-specific blood flow analysis based on feedback control theory called the physically consistent feedback control-based data assimilation (PFC-DA) method. In the PFC-DA method, the signal, which is the residual error term of the velocity when comparing the numerical and reference measurement data, is cast as a source term in a Poisson equation for the scalar potential field that induces flow in a closed system. The pressure values at the inlet and outlet boundaries are recursively calculated by this scalar potential field...
June 15, 2017: International Journal for Numerical Methods in Biomedical Engineering
keyword
keyword
79756
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"