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cerebral blood flow velocity

Peiying Liu, Ying Qi, Zixuan Lin, Qiyong Guo, Xiaoming Wang, Hanzhang Lu
Abnormal cerebral blood flow (CBF) is implicated in several neonatal and infant diseases. However, measurement of CBF in this population remains difficult and has not been used in routine clinical MRI. Arterial spin labeling (ASL) methods suffer from both low SNR and poor quantification when applied to very young children. Furthermore, rapid change in brain physiology in this age range makes it difficult to choose sequence parameters such as labeling pulse flip angle and post labeling delay. Phase-contrast (PC) MRI is another approach to measure flow...
March 10, 2018: NeuroImage
Michael Furian, Sara E Hartmann, Tsogyal D Latshang, Deborah Flueck, Christian Murer, Philipp M Scheiwiller, Batyr Osmonov, Silvia Ulrich, Malcolm Kohler, Marc J Poulin, Konrad E Bloch
BACKGROUND: Effects of hypobaric hypoxia at altitude on exercise performance of lowlanders with chronic obstructive pulmonary disease (COPD) have not been studied in detail. OBJECTIVES: To quantify changes in exercise performance and associated physiologic responses in lowlanders with COPD travelling to moderate altitude. METHODS: A total of 31 COPD patients with a median age (quartiles) of 66 years (59; 69) and FEV1 of 56% predicted (49; 69) living below 800 m performed a constant-load bicycle exercise to exhaustion at 60% of the maximal work rate at 490 m (Zurich) and at an identical work rate at 2,590 m (Davos) in randomized order...
March 2, 2018: Respiration; International Review of Thoracic Diseases
Pedro Castro, Elsa Azevedo, Isabel Rocha, Farzaneh Sorond, Jorge M Serrador
BACKGROUND: Chronic kidney disease increases stroke incidence and severity but the mechanisms behind this cerebro-renal interaction are mostly unexplored. Since both vascular beds share similar features, microvascular dysfunction could be the possible missing link. Therefore, we examined the relationship between renal function and cerebral autoregulation in the early hours post ischemia and its impact on outcome. METHODS: We enrolled 46 ischemic strokes (middle cerebral artery)...
March 2, 2018: BMC Neurology
Sushmita Purkayastha, Kaitlyn Maffuid, Xiaojie Zhu, Rong Zhang, Peter B Raven
PURPOSE: This preliminary study tested the hypothesis that the carotid baroreflex (CBR) mediated sympathoexcitation regulates cerebral blood flow (CBF) at rest and during dynamic exercise. METHODS: In seven healthy subjects (26 ± 1 years), oscillatory neck pressure (NP) stimuli of + 40 mmHg were applied to the carotid baroreceptors at a pre-determined frequency of 0.1 Hz at rest, low (10 ± 1W), and heavy (30 ± 3W) exercise workloads (WLs) without (control) and with α - 1 adrenoreceptor blockade (prazosin)...
March 1, 2018: European Journal of Applied Physiology
Sharon L Cheatham, Joanne L Chisolm, Nicole O'Brien
Hypoplastic left heart syndrome (HLHS) palliation may result in altered cerebral blood flow with subsequent neurodevelopmental implications. The purpose of the study was to assess blood flow in the middle cerebral artery (MCA) and investigate the relationship with early neurodevelopmental outcomes in infants with HLHS after hybrid stage I. Transcranial Doppler (TCD) was performed to obtain peak systolic, end-diastolic, and mean velocities, as well as pulsatility index of the MCA in infants with HLHS (n = 18) at baseline and at 2, 4, and 6 months of age...
March 2, 2018: Pediatric Cardiology
Cihan Inan, N Cenk Sayin, Zehra N Dolgun, Selen G Erzincan, Isil Uzun, Havva Sutcu, Necdet Sut, Fusun G Varol
OBJECTIVE: To evaluate the possible effects of prenatal steroid administration on Doppler parameters of the umbilical artery, uterine artery, middle cerebral artery, and ductus venosus, the cerebroplacental ratio, and the amniotic fluid index in preterm fetuses. METHODS: The present prospective observational study was performed at the Perinatology Department of Trakya University, Edirne, Turkey, between June 1, 2015, and September 1, 2016. It included patients with healthy singleton pregnancies who had received betamethasone at 24-34 weeks of pregnancy...
March 1, 2018: International Journal of Gynaecology and Obstetrics
Kyriaki Kostoglou, Ronald Schondorf, Julie Benoit, Saharnaz Balegh, Georgios D Mitsis
OBJECTIVE: In this study we aimed to predict the time to syncope occurrence (TSO) in patients with vasovagal syncope (VVS), solely based on measurements recorded during the supine position of the head-up tilt (HUT) testing protocol. METHODS: We extracted various time and frequency domain features related to morphological aspects of arterial blood pressure (ABP) and the electrocardiogram (ECG) raw signals as well as to dynamic interactions between beat-to-beat ABP, heart rate, and cerebral blood flow velocity...
2018: Acta Neurochirurgica. Supplement
Denis E Bragin, Gloria L Statom, Edwin M Nemoto
OBJECTIVE: In previous work we showed that high intracranial pressure (ICP) in the rat brain induces a transition from capillary (CAP) to pathological microvascular shunt (MVS) flow, resulting in brain hypoxia, edema, and blood-brain barrier (BBB) damage. This transition was correlated with a loss of cerebral blood flow (CBF) autoregulation undetected by static autoregulatory curves but identified by induced dynamic ICP (iPRx) and cerebrovascular (iCVRx) reactivity. We hypothesized that loss of CBF autoregulation as correlated with MVS flow would be identified by iPRx and iCVRx in traumatic brain injury (TBI) with elevated ICP...
2018: Acta Neurochirurgica. Supplement
Alexander D Wright, Jonathan D Smirl, Kelsey Bryk, Paul van Donkelaar
OBJECTIVE: To determine whether acute sports-related concussion (SRC) exerts differential effects on cerebral autoregulatory properties during systole versus diastole. MATERIALS AND METHODS: One hundred and thirty-six contact-sport athletes tested preseason; 14 sustained a concussion and completed follow-up testing at 72 hours, 2 weeks, and 1 month post-injury. Five minutes of repetitive squat-stand maneuvers induced blood pressure (BP) oscillations at both 0.05 and 0...
2018: Acta Neurochirurgica. Supplement
Solventa Krakauskaite, Corey Thibeault, James LaVangie, Mateo Scheidt, Leo Martinez, Danielle Seth-Hunter, Amanda Wu, Michael O'Brien, Fabien Scalzo, Seth J Wilk, Robert B Hamilton
OBJECTIVE: To determine normal ranges for traditional transcranial Doppler (TCD) measurements for two age groups (14-19 and 20-29 years) and compare to existing literature results. The development of a normal range for TCD measurements will be required for the development of diagnostic and prognostic tests in the future. MATERIALS AND METHODS: We performed TCD on the middle cerebral artery on 147 healthy subjects aged 18.9 years (SD = 2.1) and calculated mean cerebral blood flow velocity (mCBFV) and pulsatility index (PI)...
2018: Acta Neurochirurgica. Supplement
Jonathan D Smirl, Alexander D Wright, Philip N Ainslie, Yu-Chieh Tzeng, Paul van Donkelaar
OBJECTIVE: Cerebral pressure-flow dynamics are typically reported between mean arterial pressure and mean cerebral blood velocity. However, by reporting only mean responses, potential differential regulatory properties associated with systole and diastole may have been overlooked. MATERIALS AND METHODS: Twenty young adults (16 male, age: 26.7 ± 6.6 years, BMI: 24.9 ± 3.0 kg/m2 ) were recruited for this study. Middle cerebral artery velocity was indexed via transcranial Doppler...
2018: Acta Neurochirurgica. Supplement
Andrea Fanelli, Rohan Jaishankar, Aristotelis Filippidis, James Holsapple, Thomas Heldt
OBJECTIVES:  Our objective was to develop, deploy, and test a data-acquisition system for the reliable and robust archiving of high-resolution physiological waveform data from a variety of bedside monitoring devices, including the GE Solar 8000i patient monitor, and for the logging of ancillary clinical and demographic information. MATERIALS AND METHODS:  The data-acquisition system consists of a computer-based archiving unit and a GE Tram Rac 4A that connects to the GE Solar 8000i monitor...
2018: Acta Neurochirurgica. Supplement
Max Chacón, Sun-Ho Noh, Jean Landerretche, José L Jara
OBJECTIVE: We analyzed the performance of linear and nonlinear models to assess dynamic cerebral autoregulation (dCA) from spontaneous variations in healthy subjects and compared it with the use of two known maneuvers to abruptly change arterial blood pressure (BP): thigh cuffs and sit-to-stand. MATERIALS AND METHODS: Cerebral blood flow velocity and BP were measured simultaneously at rest and while the maneuvers were performed in 20 healthy subjects. To analyze the spontaneous variations, we implemented two types of models using support vector machine (SVM): linear and nonlinear finite impulse response models...
2018: Acta Neurochirurgica. Supplement
Peter Smielewski, Luzius Steiner, Corina Puppo, Karol Budohoski, Georgios V Varsos, Marek Czosnyka
OBJECTIVE: Brain arterial critical closing pressure (CrCP) has been studied in several diseases such as traumatic brain injury (TBI), subarachnoid haemorrhage, hydrocephalus, and in various physiological scenarios: intracranial hypertension, decreased cerebral perfusion pressure, hypercapnia, etc. Little or nothing so far has been demonstrated to characterise change in CrCP during mild hypocapnia. METHOD: We retrospectively analysed recordings of intracranial pressure (ICP), arterial blood pressure (ABP) and blood flow velocity from 27 severe TBI patients (mean 39...
2018: Acta Neurochirurgica. Supplement
Katarzyna Kaczmarska, Magdalena Kasprowicz, Antoni Grzanka, Wojciech Zabołotny, Peter Smielewski, Despina Afroditi Lalou, Georgios Varsos, Marek Czosnyka, Zofia Czosnyka
OBJECTIVES: The objectives were to compare three methods of estimating critical closing pressure (CrCP) in a scenario of a controlled increase in intracranial pressure (ICP) induced during an infusion test in patients with suspected normal pressure hydrocephalus (NPH). METHODS: We retrospectively analyzed data from 37 NPH patients who underwent infusion tests. Computer recordings of directly measured intracranial pressure (ICP), arterial blood pressure (ABP) and transcranial Doppler cerebral blood flow velocity (CBFV) were used...
2018: Acta Neurochirurgica. Supplement
Eline J Vinke, Jens Eyding, Chris de Korte, Cornelis H Slump, Johannes G van der Hoeven, Cornelia W E Hoedemaekers
OBJECTIVE: The aim of this study was to investigate the feasibility of simultaneous visualization of the cerebral macrocirculation and microcirculation, using ultrasound perfusion imaging (UPI). In addition, we studied the sensitivity of this technique for detecting changes in cerebral blood flow (CBF). MATERIALS AND METHODS: We performed an observational study in ten healthy volunteers. Ultrasound contrast was used for UPI measurements during normoventilation and hyperventilation...
2018: Acta Neurochirurgica. Supplement
Sabino J Pietrangelo, Hae-Seung Lee, Charles G Sodini
OBJECTIVE:  Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. MATERIALS AND METHODS: A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing...
2018: Acta Neurochirurgica. Supplement
Denis E Bragin, Olga A Bragina, Sean Hagberg, Edwin M Nemoto
OBJECTIVE: High-frequency pulsed electromagnetic field (PEMF) stimulation is an emerging noninvasive therapy that we have shown increases cerebral blood flow (CBF) and tissue oxygenation in the healthy rat brain. In this work, we tested the effect of PEMF on the brain at high intracranial pressure (ICP). We previously showed that high ICP in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow, tissue hypoxia and increased blood brain barrier (BBB) permeability...
2018: Acta Neurochirurgica. Supplement
Jonathan M Matthews, Andrea Fanelli, Thomas Heldt
OBJECTIVE: The monitoring of intracranial pressure (ICP) is indicated for diagnosing and guiding therapy in many neurological conditions. Current monitoring methods, however, are highly invasive, limiting their use to the most critically ill patients only. Our goal is to develop and test an embedded device that performs all necessary mathematical operations in real-time for noninvasive ICP (nICP) estimation based on a previously developed model-based approach that uses cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) waveforms...
2018: Acta Neurochirurgica. Supplement
Bernhard Schmidt, Danilo Cardim, Marco Weinhold, Stefan Streif, Damian D McLeod, Marek Czosnyka, Jürgen Klingelhöfer
OBJECTIVE: Previously we described the method of continuous intracranial pressure (ICP) estimation using arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). The model was constructed using reference patient data. Various individual calibration strategies were used in the current attempt to improve the accuracy of this non-invasive ICP (nICP) assessment tool. MATERIALS AND METHODS: Forty-one patients (mean, 52 years; range, 18-77 years) with severe brain injuries were studied...
2018: Acta Neurochirurgica. Supplement
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