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Cerebral hemodynamic

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https://www.readbyqxmd.com/read/29027859/quantitative-cerebral-blood-flow-using-xenon-enhanced-ct-after-decompressive-craniectomy-in-traumatic-brain-injury
#1
Aditya Vedantam, Claudia S Robertson, Shankar P Gopinath
OBJECTIVE Few studies have reported on changes in quantitative cerebral blood flow (CBF) after decompressive craniectomy and the impact of these measures on clinical outcome. The aim of the present study was to evaluate global and regional CBF patterns in relation to cerebral hemodynamic parameters in patients after decompressive craniectomy for traumatic brain injury (TBI). METHODS The authors studied clinical and imaging data of patients who underwent xenon-enhanced CT (XeCT) CBF studies after decompressive craniectomy for evacuation of a mass lesion and/or to relieve intractable intracranial hypertension...
October 13, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29025902/relative-contributions-of-systemic-hemodynamic-variables-to-cerebral-autoregulation-during-orthostatic-stress
#2
Hisao Yoshida, Jason W Hamner, Keita Ishibashi, Can Ozan Tan
Postural changes impair the ability of the cerebrovasculature to buffer against dynamic pressure fluctuations, but the mechanisms underlying this impairment have not been elucidated. We hypothesized that autoregulatory impairment may reflect the impact of static central volume shifts on hemodynamic factors other than arterial pressure (AP). In 14 young volunteers, we assessed the relation of fluctuations in cerebral blood flow (CBF) to those in AP, cardiac output, and CO2, during oscillatory lower body pressure (LBP) (±20 mmHg at 0...
October 12, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/29025748/compromised-cerebrovascular-regulation-and-cerebral-oxygenation-in-pulmonary-arterial-hypertension
#3
Simon Malenfant, Patrice Brassard, Myriam Paquette, Olivier Le Blanc, Audrey Chouinard, Valérie Nadeau, Philip D Allan, Yu-Chieh Tzeng, Sébastien Simard, Sébastien Bonnet, Steeve Provencher
BACKGROUND: Functional cerebrovascular regulatory mechanisms are important for maintaining constant cerebral blood flow and oxygen supply in heathy individuals and are altered in heart failure. We aim to examine whether pulmonary arterial hypertension (PAH) is associated with abnormal cerebrovascular regulation and lower cerebral oxygenation and their physiological and clinical consequences. METHODS AND RESULTS: Resting mean flow velocity in the middle cerebral artery mean flow velocity in the middle cerebral artery (MCAvmean); transcranial Doppler), cerebral pressure-flow relationship (assessed at rest and during squat-stand maneuvers; analyzed using transfer function analysis), cerebrovascular reactivity to CO2, and central chemoreflex were assessed in 11 patients with PAH and 11 matched healthy controls...
October 12, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/29024300/accounting-for-the-role-of-hematocrit-in-between-subject-variations-of-mri-derived-baseline-cerebral-hemodynamic-parameters-and-functional-bold-responses
#4
Feng Xu, Wenbo Li, Peiying Liu, Jun Hua, John J Strouse, James J Pekar, Hanzhang Lu, Peter C M van Zijl, Qin Qin
Baseline hematocrit fraction (Hct) is a determinant for baseline cerebral blood flow (CBF) and between-subject variation of Hct thus causes variation in task-based BOLD fMRI signal changes. We first verified in healthy volunteers (n = 12) that Hct values can be derived reliably from venous blood T1 values by comparison with the conventional lab test. Together with CBF measured using phase-contrast MRI, this noninvasive estimation of Hct, instead of using a population-averaged Hct value, enabled more individual determination of oxygen delivery (DO2 ), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2 )...
October 11, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29023958/stroke-induced-chronic-systolic-dysfunction-driven-by-sympathetic-overactivity
#5
Michael Bieber, Rudolf A Werner, Edit Tanai, Ulrich Hofmann, Takahiro Higuchi, Kai Schuh, Peter U Heuschmann, Stefan Frantz, Oliver Ritter, Peter Kraft, Christoph Kleinschnitz
OBJECTIVE: Cardiac diseases are established risk factors for ischemic stroke incidence and severity. Conversely, there is increasing evidence that brain ischemia can cause cardiac dysfunction. The mechanisms underlying this neurogenic heart disease are incompletely understood. While it is established that ischemic stroke is associated with cardiac arrhythmias, myocardial damage, elevated cardiac enzymes and plasma catecholamines in the acute phase, nothing is known about the delayed consequences of ischemic stroke on cardiovascular function...
October 10, 2017: Annals of Neurology
https://www.readbyqxmd.com/read/29021986/integrated-treatment-modality-of-cathodal-transcranial-direct-current-stimulation-with-peripheral-sensory-stimulation-affords-neuroprotection-in-a-rat-stroke-model
#6
Yu-Hang Liu, Su Jing Chan, Han-Chi Pan, Aishwarya Bandla, Nicolas K K King, Peter Tsun Hon Wong, You-Yin Chen, Wai Hoe Ng, Nitish V Thakor, Lun-De Liao
Cathodal-transcranial direct current stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral sensory stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/29018652/anastomotic-aneurysm-formation-after-high-flow-bypass-surgery-a-case-report-with-histopathological-study
#7
Tatsuya Uchida, Masanori Yoshino, Shinji Ito, Takayuki Hara
Bypass surgery is often used in the treatment of large and giant aneurysms. Major complications that often arise during the perioperative period include cranial nerve palsy, ischemic complications, and hyperperfusion. However, there have been a few reports about late onset complications such as anastomotic aneurysms. In particular, anastomotic aneurysm after high flow bypasses has never been reported. A 57-year-old woman who had been suffering from left eye pain was diagnosed with a large aneurysm of the left internal carotid artery (ICA) in the cavernous portion...
October 2017: NMC Case Rep J
https://www.readbyqxmd.com/read/28993442/in-room-assessment-of-intravascular-velocity-from-time-resolved-rotational-angiography-in-patients-with-arteriovenous-malformation-a-pilot-study
#8
Chung Jung Lin, Huai Che Yang, Ai Chi Chien, Wan Yuo Guo, Chih Chun Wu, Sheng Che Hung, Ko Kung Chen, Hsiu Mei Wu, Chao Bao Luo, Wei Fa Chu, Jia Sheng Hong, Chun Shien Frank Wu
BACKGROUND: Time-resolved rotational angiography (t-RA) enables interventionists to better comprehend complex arteriovenous malformations (AVMs), thereby facilitating endovascular treatment. However, its use in evaluating hemodynamic changes has rarely been explored. OBJECTIVE: This study uses t-RA to estimate intravascular flow in patients with AVM to compare this with flow in the normal population. METHODS: Patients with available t-RA scans were prospectively categorized into one of three groups: hemorrhagic AVM, non-hemorrhagic AVM and control...
October 9, 2017: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/28992237/impacts-of-metabolic-syndrome-scores-on-cerebrovascular-conductance-are-mediated-by-arterial-stiffening
#9
Evan P Pasha, Alex C Birdsill, Stephanie Oleson, Andreana P Haley, Hirofumi Tanaka
BACKGROUND: Individuals with metabolic syndrome (MetS) exhibit reduced cerebral blood flow. The mechanisms of this reduction remain unknown but arterial stiffening has been implicated as a contributor. We determined if MetS was associated with reduced cerebral blood flow at midlife, and if so, whether arterial stiffness was responsible for mediating their relation. METHODS: Middle-aged (40-60 years) community dwelling adults (n = 83) were studied. MetS score was calculated for each subject...
July 31, 2017: American Journal of Hypertension
https://www.readbyqxmd.com/read/28991702/cerebral-autoregulation-is-preserved-in-multiple-sclerosis-patients
#10
Daniel Ferreira, Pedro Castro, Gonçalo Videira, João Pedro Filipe, Rosa Santos, Maria José Sá, Elsa Azevedo, Pedro Abreu
Multiple sclerosis (MS) is an inflammatory disease that may also be associated with vascular dysfunction. One master component of vascular regulation is cerebral autoregulation (CA). We aimed to investigate the integrity of CA in MS patients and study its relationship with autonomic dysfunction (AD), magnetic-resonance-imaging (MRI) lesion load and hemodynamic parameters. We enrolled 20 relapsing-remitting MS and 20 healthy subjects. CA was assessed by transfer function analysis parameters (coherence, gain and phase), as obtained in the very low, low and high-frequency domains (VLF, LF, HF, respectively)...
October 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28991060/hemodynamic-instability-and-cardiovascular-events-after-traumatic-brain-injury-predict-outcome-after-artifact-removal-with-deep-belief-network-analysis
#11
Hakseung Kim, Seung-Bo Lee, Yunsik Son, Marek Czosnyka, Dong-Joo Kim
BACKGROUND: Hemodynamic instability and cardiovascular events heavily affect the prognosis of traumatic brain injury. Physiological signals are monitored to detect these events. However, the signals are often riddled with faulty readings, which jeopardize the reliability of the clinical parameters obtained from the signals. A machine-learning model for the elimination of artifactual events shows promising results for improving signal quality. However, the actual impact of the improvements on the performance of the clinical parameters after the elimination of the artifacts is not well studied...
October 5, 2017: Journal of Neurosurgical Anesthesiology
https://www.readbyqxmd.com/read/28987853/early-hemodynamic-changes-based-on-initial-color-coding-angiography-as-a-predictor-for-developing-subsequent-symptomatic-vasospasm-after-aneurysmal-sah
#12
Jan-Karl Burkhardt, Xiaolin Chen, Ethan A Winkler, Miriam Weiss, John Yue, Daniel L Cooke, Helen Kim, Michael T Lawton
INTRODUCTION: Prediction of vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) remains imperfect and currently relies on clinical and radiographic characteristics. Whether early hemodynamic changes may refine risk stratification for delayed vasospasm (DV) after aSAH was analyzed. METHODS: Patients with aSAH (n=53) and a control of unruptured intracranial aneurysms (UIA) (n=12) with initial color-coding angiography at admission were included in this study (n=65)...
October 5, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28984599/sleep-apnea-cognitive-profile-and%C3%A2-vascular-changes-an-intriguing-relationship
#13
Laura Buratti, Giovanna Viticchi, Sara Baldinelli, Lorenzo Falsetti, Simona Luzzi, Alessandra Pulcini, Cristina Petrelli, Leandro Provinciali, Mauro Silvestrini
BACKGROUND: Sleep breathing disorders can affect cognitive performances through complex brain anatomical and functional changes. OBJECTIVE: Our aim was to evaluate the correlations between cognitive performances and obstructive sleep apnea syndrome (OSAS), as well as the possible influence of vascular factors. METHODS: Thirty-four non-demented OSAS patients and 34 controls were submitted to a neuropsychological evaluation and to a vascular screening including the study of cerebrovascular reactivity by means of the breath-holding index (BHI) calculation...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28983491/mean-and-variability-in-functional-brain-activations-differentially-predict-executive-function-in-older-adults-an-investigation-employing-functional-near-infrared-spectroscopy
#14
Drew W R Halliday, Bryce P Mulligan, Douglas D Garrett, Stefan Schmidt, Sandra R Hundza, Mauricio A Garcia-Barrera, Robert S Stawski, Stuart W S MacDonald
OBJECTIVE: although the preponderance of research on functional brain activity investigates mean group differences, mounting evidence suggests that variability in neural activity is beneficial for optimal central nervous system (CNS) function. Independent of mean signal estimates, recent findings have shown that neural variability diminishes with age and is positively associated with cognitive performance, underscoring its adaptive nature. The present investigation sought to employ functional near infrared spectroscopy (fNIRS) to derive two operationalizations of cerebral oxygenation, representing mean and variability [using standard deviation (SD)] in neural activity, and to specifically contrast these mean- and SD-oxyhemoglobin (HbO) estimates as predictors of cognitive function...
January 2018: Neurophotonics
https://www.readbyqxmd.com/read/28982786/preoperative-cerebral-oxygen-extraction-fraction-imaging-generated-from-7t-mr-quantitative-susceptibility-mapping-predicts-development-of-cerebral-hyperperfusion-following-carotid-endarterectomy
#15
J-I Nomura, I Uwano, M Sasaki, K Kudo, F Yamashita, K Ito, S Fujiwara, M Kobayashi, K Ogasawara
BACKGROUND AND PURPOSE: Preoperative hemodynamic impairment in the affected cerebral hemisphere is associated with the development of cerebral hyperperfusion following carotid endarterectomy. Cerebral oxygen extraction fraction images generated from 7T MR quantitative susceptibility mapping correlate with oxygen extraction fraction images on positron-emission tomography. The present study aimed to determine whether preoperative oxygen extraction fraction imaging generated from 7T MR quantitative susceptibility mapping could identify patients at risk for cerebral hyperperfusion following carotid endarterectomy...
October 5, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28979924/postural-hypotension-and-cognitive-function-in-older-adults
#16
Kenneth J McLeod, Teesta Jain
Background: Cognitive decline in the elderly is associated with chronic cerebral hypoperfusion. While many forms of exercise can slow or reverse cognitive decline, compliance in unsupervised exercise programs is poor. Objective: We address whether passive exercise, that is, muscle stimulation, is capable of reversing postural hypotension in an older adult population sufficiently to significantly improve cognitive function as measured by executive function tests. Subjects and Methods: In this study, 50- to 80-year-old women underwent cognitive testing, long-duration cardiac hemodynamic recordings during quiet sitting, and 60 min of soleus muscle stimulation with continued hemodynamic recording...
January 2017: Gerontology & Geriatric Medicine
https://www.readbyqxmd.com/read/28974452/long-term-optical-imaging-of-neurovascular-coupling-in-mouse-cortex-using-gcamp6f-and-intrinsic-hemodynamic-signals
#17
Xiaochun Gu, Wei Chen, Jiang You, Alan P Koretsky, N D Volkow, Yingtian Pan, Congwu Du
Cerebral hemodynamics is modulated in response to changes in neuronal activity, a process termed neurovascular coupling (NVC), which can be disrupted by neuropsychiatric diseases (e.g., stroke, Alzheimer's disease). Thus, there is growing interest to image long-term NVC dynamics with high spatiotemporal resolutions. Here, by combining the use of a genetically-encoded calcium indicator with optical techniques, we develop a longitudinal multimodal optical imaging platform (MIP) that enabled time-lapse tracking of NVC over a relatively large field of view in the mouse somatosensory cortex at single cell and single vessel resolutions...
September 30, 2017: NeuroImage
https://www.readbyqxmd.com/read/28973579/cerebrovascular-imaging-which-test-is-best
#18
Amy Lin, Sapna Rawal, Ronit Agid, Daniel M Mandell
Optimal diagnosis and characterization of cerebrovascular disease requires selection of the appropriate imaging exam for each clinical situation. In this review, we focus on intracranial arterial disease and discuss the techniques in current clinical use for imaging the blood vessel lumen and blood vessel wall, and for mapping cerebral hemodynamic impairment at the tissue level. We then discuss specific strategies for imaging intracranial aneurysms, arteriovenous malformations, dural arterial venous fistulas, and arterial steno-occlusive disease...
June 23, 2017: Neurosurgery
https://www.readbyqxmd.com/read/28972127/functional-characterization-of-5-ht1b-receptor-drugs-in-non-human-primates-using-simultaneous-pet-mr
#19
Hanne D Hansen, Joseph B Mandeville, Christin Y Sander, Jacob M Hooker, Ciprian Catana, Bruce R Rosen, Gitte M Knudsen
In the present study, we used a simultaneous PET-MR experimental design to investigate the effects of functionally different compounds (agonist, partial agonist and antagonist) on 5-HT1B receptor (5-HT1BR) occupancy and the associated hemodynamic responses. In anaesthetized male non-human primates (NHP, n=3), we used PET imaging with the radioligand [(11)C]AZ10419369 administered as a bolus followed by constant infusion to measure changes in 5-HT1BR occupancy. Simultaneously, we measured changes in cerebral blood volume (CBV) as a proxy of drug effects on neuronal activity...
October 2, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28971699/cgrp-receptor-antagonist-mk-8825-attenuates-cortical-spreading-depression-induced-pain-behavior
#20
Aslı Filiz, Nermin Tepe, Sajedeh Eftekhari, H Evren Boran, Ergin Dilekoz, Lars Edvinsson, Hayrunnisa Bolay
Background and objective The present study aimed to investigate the effects of selective calcitonin gene related peptide (CGRP) receptor antagonist (MK-8825) on cortical spreading depression (CSD) induced pain behavior and anxiety in freely-moving rats, and neuronal activation in the correlated anatomical regions. Methods CSD was induced while keeping all meningeal layers and BBB intact and MK-8825 was administered in two different doses. Regional cerebral blood flow (rCBF), arterial pressure and DC shift were recorded...
January 1, 2017: Cephalalgia: An International Journal of Headache
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