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cerebral hemodynamics

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https://www.readbyqxmd.com/read/29220356/color-doppler-ultrasonography-as-an-alternative-tool-for-postoperative-evaluation-of-collaterals-after-indirect-revascularization-surgery-in-moyamoya-disease
#1
Shin-Joe Yeh, Sung-Chun Tang, Li-Kai Tsai, Chung-Wei Lee, Ya-Fang Chen, Hon-Man Liu, Shih-Hung Yang, Meng-Fai Kuo, Jiann-Shing Jeng
The cerebral hypoperfusion caused by chronic progressive stenosis or occlusion of intracranial arteries in moyamoya disease can be treated by direct bypass or indirect revascularization procedures. The extent of collaterals from the external carotid artery (ECA) after indirect revascularization surgery is the key point of angiographic follow-up, and the invasiveness of angiography impelled us to investigate the role of ultrasonography in the evaluation of collaterals. We hypothesized that the collaterals shown on angiography might produce corresponding hemodynamic changes in color Doppler ultrasonography...
2017: PloS One
https://www.readbyqxmd.com/read/29217405/a-novel-perspective-to-calibrate-temporal-delays-in-cerebrovascular-reactivity-using-hypercapnic-and-hyperoxic-respiratory-challenges
#2
Allen A Champagne, Alex A Bhogal, Nicole S Coverdale, Clarisse I Mark, Douglas J Cook
Redistribution of blood flow across different brain regions, arising from the vasoactive nature of hypercapnia, can introduce errors when examining cerebrovascular reactivity (CVR) response delays. In this study, we propose a novel analysis method to characterize hemodynamic delays in the blood oxygen level dependent (BOLD) response to hypercapnia, and hyperoxia, as a way to provide insight into transient differences in vascular reactivity between cortical regions, and across tissue depths. A pseudo-continuous arterial spin labeling sequence was used to acquire BOLD and cerebral blood flow simultaneously in 19 healthy adults (12 F; 20 ± 2 years) during boxcar CO2 and O2 gas inhalation paradigms...
December 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/29217363/positional-brain-single-photon-emission-computed-tomography-findings-in-a-case-of-limb-shaking-syndrome
#3
Caroline Bund, Céline Heimburger, Valérie Wolff, Izzie Jacques Namer
An 84-year-old man, who presented lower limbs limb-shaking syndrome at orthostatism lasting a few seconds, was referred in our stroke unit. Magnetic resonance imaging showed an acute infarction in the right thalamus and the insular cortex, left extracranial carotid stenosis at 80%, and low flow in the right middle cerebral artery but did not explain limb-shaking syndrome symptomatology. We performed comparative positional brain perfusion single-photon emission computed tomography (SPECT), in the upright and in the supine position, to explore and localize hypoperfusion-endangered brain structures that may be involved in the presenting symptoms...
December 4, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/29212618/altered-cerebral-perfusion-in-infants-born-preterm-compared-with-infants-born-full-term
#4
Marine Bouyssi-Kobar, Jonathan Murnick, Marie Brossard-Racine, Taeun Chang, Eman Mahdi, Marni Jacobs, Catherine Limperopoulos
OBJECTIVES: To compare regional cerebral cortical blood flow (CBF) in infants born very preterm at term-equivalent age (TEA) and healthy newborns born full term and to examine the impact of clinical risk factors on CBF in the cohort born preterm. STUDY DESIGN: This prospective, cross-sectional study included infants born very preterm (gestational age at birth <32 weeks; birth weight <1500 g) and healthy infants born full term. Using noninvasive 3T arterial spin labeling magnetic resonance imaging, we quantified regional CBF in the cerebral cortex: sensorimotor/auditory/visual cortex, superior medial/dorsolateral prefrontal cortex, anterior cingulate cortex (ACC)/posterior cingulate cortex, insula, and lateral posterior parietal cortex, as well as in the brainstem, and deep gray matter...
November 30, 2017: Journal of Pediatrics
https://www.readbyqxmd.com/read/29209882/hemodynamics-of-focal-versus-global-growth-of-small-cerebral-aneurysms
#5
Paolo Machi, Rafik Ouared, Olivier Brina, Pierre Bouillot, Hasan Yilmaz, Maria I Vargas, Renato Gondar, Philippe Bijlenga, Karl O Lovblad, Zsolt Kulcsár
BACKGROUND AND PURPOSE: Hemodynamics play a driving role in the life cycle of brain aneurysms from initiation through growth until eventual rupture. The specific factors behind aneurysm growth, especially in small aneurysms, are not well elucidated. The goal of this study was to differentiate focal versus general growth and to analyze the hemodynamic microenvironment at the sites of enlargement in small cerebral aneurysms. MATERIALS AND METHODS: Small aneurysms showing growth during follow-up were identified from our prospective aneurysm database...
December 5, 2017: Clinical Neuroradiology
https://www.readbyqxmd.com/read/29205172/a-data-driven-approach-for-addressing-the-lack-of-flow-waveform-data-in-studies-of-cerebral-arterial-flow-in-older-adults
#6
Michael J Durka, Isaac Hong Wong, David F Kallmes, Dario Pasalic, Fernando Mut, Manoj Jagani, Pablo J Blanco, Juan R Cebral, Anne M Robertson
Blood flow waveforms - essential data for hemodynamic modeling - are often in practice unavailable to researchers. The objectives of this work were to assess the variability among the waveforms for a clinically relevant older population, and develop data-based methods for addressing the missing waveform data for hemodynamic studies. Approach: We analyzed 272 flow waveforms from the internal carotid arteries of older patients (73±13 years) with moderate cardiovascular disease, and used these data to develop approaches to guide new approaches for hemodynamic studies...
December 5, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29203738/mathematical-model-of-diabetic-encephalopathy
#7
Alla A Popruha, Lyudmyla E Bobyreva, Larisa A Samarchenko, Tatyana E Mykhaylychenko
INTRODUCTION: Diabetes mellitus (DM) is one of the leading risk factors for cerebrovascular disorders. The risk of stroke is 3-4 times higher in this population. In 10% of cases of vascular accidents in diabetic patients leads to fatal. The mortality rate for ischemic stroke is undergoing 50-60% and 70-95% of hemorrhagic form. It is known that diabetes increases the course of acute disorders of cerebral circulation. At the same time, there are data that about 415 million of the inhabitants of the planet suffer from diabetes, in 95% of cases they have type 2 diabetes, which is the second risk factor for the development of ischemic stroke after an arterial hypertension...
2017: Wiadomości Lekarskie: Organ Polskiego Towarzystwa Lekarskiego
https://www.readbyqxmd.com/read/29203409/nanoelectronics-enabled-chronic-multimodal-neural-platform-in-a-mouse-ischemic-model
#8
Lan Luan, Colin T Sullender, Xue Li, Zhengtuo Zhao, Hanlin Zhu, Xiaoling Wei, Chong Xie, Andrew K Dunn
BACKGROUND: Despite significant advancements of optical imaging techniques for mapping hemodynamics in small animal models, it remains challenging to combine imaging with spatially resolved electrical recording of individual neurons especially for longitudinal studies. This is largely due to the strong invasiveness to the living brain from the penetrating electrodes and their limited compatibility with longitudinal imaging. NEW METHOD: We implant arrays of ultraflexible nanoelectronic threads (NETs) in mice for neural recording both at the brain surface and intracortically, which maintain great tissue compatibility chronically...
December 1, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29203170/diameter-of-fluorescent-microspheres-determines-their-distribution-throughout-the-cortical-watershed-area-in-mice
#9
Naoki Tsukada, Masahiro Katsumata, Koichi Oki, Kazushi Minami, Takato Abe, Shinichi Takahashi, Yoshiaki Itoh, Norihiro Suzuki
A hemodynamic mechanism has long been assumed to play an important role in watershed infarction. In recent years, however, clinical evidence has indicated that an embolic mechanism is involved. The mechanism by which emboli are trapped preferentially in watershed areas remains unclear. In the present study, we developed a mouse embolus model using fluorescent microspheres with different diameters and evaluated the role of the microspheres' diameters in the generation of a watershed-patterned distribution. We injected fluorescent microspheres of four different diameters (i...
December 1, 2017: Brain Research
https://www.readbyqxmd.com/read/29195758/light-up-adhd-i-cortical-hemodynamic-responses-measured-by-functional-near-infrared-spectroscopy-fnirs
#10
REVIEW
Maddalena Mauri, Maria Nobile, Monica Bellina, Alessandro Crippa, Paolo Brambilla
BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by deficits in cognitive and emotional self-control. Optical technique acquisitions, such as near infrared spectroscopy (NIRS), seem to be very promising during developmental ages, as they are non- invasive techniques and less influenced by body movements than other neuroimaging methods. Recently, these new techniques are being widely used to measure neural correlates underlying neuropsychological deficits in children with ADHD...
November 21, 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/29193158/terlipressin-induced-modifications-of-doppler-ultrasound-signals-of-systemic-arteries-in-preterm-infants-with-vasoactive-resistant-patent-ductus-arteriosus-a-pilot-study
#11
M Radicioni, V Bini, G M Campus, P G Camerini
PURPOSE: To study the effects of terlipressin (TP) infusion on systemic perfusion, estimated with pulsed-wave Doppler ultrasonography of systemic arteries, in a population of extremely low birth-weight (ELBW) preterm infants with vasoactive-resistant ductus arteriosus. METHODS: This prospective, observational cohort included, during five years, 12 ELBW infants with hemodynamically significant patent ductus arteriosus and absent or reversed diastolic flow at Doppler ultrasonography of systemic arteries, despite treatment and high-dose vasoactive support...
November 28, 2017: Journal of Clinical Ultrasound: JCU
https://www.readbyqxmd.com/read/29191051/preoperative-evaluation-of-moyamoya-spontaneous-anastomosis-of-combined-revascularization-donor-vessels-in-adults-by-duplex-ultrasonography
#12
Li Chen, Bin Xu, Yong Wang, Yujun Liao, Huiwen Pan, Yi Wang
OBJECTIVE: To evaluate the preoperative diagnostic value of duplex ultrasonography in moyamoya spontaneous anastomosis of combined revascularization donor vessels in adults. METHODS: A total of 99 preoperative adult patients who underwent superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis were retrospectively analyzed. Each side of the cerebral hemisphere was examined as a separate procedure. A total of 198 cerebral hemispheres were divided into three groups: a collateral, non-collateral, and control group based on digital subtraction angiography (DSA)...
November 30, 2017: British Journal of Neurosurgery
https://www.readbyqxmd.com/read/29189639/effects-of-closed-endotracheal-suctioning-on-systemic-and-cerebral-oxygenation-and-hemodynamics-in-children
#13
Madhuradhar Chegondi, Teshaun Francis, Wei-Chiang Lin, Sayed Naqvi, Andre Raszynski, Balagangadhar R Totapally
OBJECTIVES: To evaluate the effects of closed endotracheal tube suctioning on systemic oxygen saturation, cerebral regional oxygen saturation, and somatic regional (renal) oxygen saturation and hemodynamic variables in children. DESIGN: Prospective observational. SETTING: A tertiary care PICU. SUBJECTS: Children aged 0-18 years, requiring invasive mechanical ventilation and with an arterial line. INTERVENTIONS: Closed endotracheal suction...
November 16, 2017: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/29188396/cerebrovascular-hemodynamics-during-the-practice-of-bhramari-pranayama-kapalbhati-and-bahir-kumbhaka-an-exploratory-study
#14
L Nivethitha, A Mooventhan, N K Manjunath, Lokesh Bathala, Vijay K Sharma
Various pranayama techniques are known to produce different physiological effects. We evaluated the effect of three-different pranayama techniques on cerebrovascular hemodynamics. Eighteen healthy volunteers with the mean ± standard deviation age of 23.78 ± 2.96 years were performed three-different pranayama techniques: (1) Bhramari, (2) Kapalbhati and (3) Bahir-Kumbhaka in three-different orders. Continuous transcranial Doppler (TCD) monitoring was performed before, during and after the pranayama techniques...
November 29, 2017: Applied Psychophysiology and Biofeedback
https://www.readbyqxmd.com/read/29184204/weak-correlations-between-hemodynamic-signals-and-ongoing-neural-activity-during-the-resting-state
#15
Aaron T Winder, Christina Echagarruga, Qingguang Zhang, Patrick J Drew
Spontaneous fluctuations in hemodynamic signals in the absence of a task or overt stimulation are used to infer neural activity. We tested this coupling by simultaneously measuring neural activity and changes in cerebral blood volume (CBV) in the somatosensory cortex of awake, head-fixed mice during periods of true rest and during whisker stimulation and volitional whisking. We found that neurovascular coupling was similar across states and that large, spontaneous CBV changes in the absence of sensory input were driven by volitional whisker and body movements...
December 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/29181427/effect-of-short-term-colored-light-exposure-on-cerebral-hemodynamics-and-oxygenation-and-systemic-physiological-activity
#16
Felix Scholkmann, Timo Hafner, Andreas Jaakko Metz, Martin Wolf, Ursula Wolf
There is not yet a comprehensive view of how the color of light affects the cerebral and systemic physiology in humans. The aim was to address this deficit through basic research. Since cerebral and systemic physiological parameters are likely to interact, it was necessary to establish an approach, which we have termed "systemic-physiology-augmented functional near-infrared spectroscopy (SPA-fNIRS) neuroimaging." This multimodal approach measures the systemic and cerebral physiological response to exposure to light of different colors...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/29173598/mechanisms-clinical-significance-and-prevention-of-cognitive-impairment-in-patients-with-atrial-fibrillation
#17
REVIEW
Lena Rivard, Paul Khairy
Atrial fibrillation (AF) and dementia are major health issues, with growing evidence suggesting a consistent association between AF and all forms of dementia. Although dementia and AF share several risk factors, the association appears to be independent of a history of clinical stroke and other comorbidities such as hypertension, heart failure, and diabetes. Proposed mechanisms linking AF to cognitive decline include altered hemodynamics resulting in cerebral hypoperfusion, inflammation, genetic factors, and silent cerebral ischemia due to subclinical microemboli...
December 2017: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/29171118/translesional-pressure-gradient-and-leptomeningeal-collateral-status-in-symptomatic-middle-cerebral-artery-stenosis
#18
Xinyi Leng, Linfang Lan, Hing Lung Ip, Florence Fan, Sze Ho Ma, Karen Ma, Haipeng Liu, Zhengzheng Yan, Jia Liu, Jill Abrigo, Yannie Oy Soo, David S Liebeskind, Ka Sing Wong, Thomas W Leung
BACKGROUND AND PURPOSE: Leptomeningeal collateral (LMC) status governs prognosis of large artery occlusive stroke, while factors determining the LMC status were not fully elucidated. We aimed to investigate metrics affecting LMC status in such patients by using computational fluid dynamics (CFD) models based on CT angiography (CTA). METHODS: In this cross-sectional study, we recruited patients with recent ischemic stroke or transient ischemic attack attributed to atherosclerotic M1 middle cerebral artery (MCA) stenosis (50-99%)...
November 24, 2017: European Journal of Neurology: the Official Journal of the European Federation of Neurological Societies
https://www.readbyqxmd.com/read/29169168/anterior-borderzone-angle-for-hemodynamic-collateral-metric-in-patients-with-symptomatic-middle-cerebral-artery-stenosis
#19
Yongkun Li, Yunyun Xiong, Qiankun Cai, Dezhi Liu, Qiliang Dai, Wenhua Liu, Zhixin Huang, Wen Sun, David S Liebeskind, Yinzhou Wang, Xinfeng Liu
BACKGROUND AND AIMS: We aimed to introduce a parameter of anterior borderzone angle (ABZA) to quantitatively evaluate the ACA-MCA leptomeningeal collaterals for middle cerebral artery stenosis (MCAS). METHODS: Two hundred seventy-five patients with 50-100% MCAS and 100 controls were included. The 95% reference range of ABZA was obtained from the controls. ABZAtrans was defined as "ABZA/the 95% upper limit." Relationships between ABZA and MCAS, -ABZAtrans and the TICI grade, the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral grade were analyzed...
November 23, 2017: European Neurology
https://www.readbyqxmd.com/read/29163674/clinical-value-of-homodynamic-numerical-simulation-applied-in-the-treatment-of-cerebral-aneurysm
#20
Hailin Zhang, Li Li, Chongjie Cheng, Xiaochuan Sun
Our objective was to evaluate the clinical value of numerical simulation in diagnosing cerebral aneurysm based on the analysis of numerical simulation of hemodynamic model. The experimental method used was the numerical model of cerebral aneurysm hemodynamic, and the numerical value of blood flow at each point was analyzed. The results showed that, the wall shear stress (WSS) value on the top of CA1 was significantly lower than that of the top (P<0.05), the WSS value of each point on the CA2 tumor was significantly lower than that of tumor neck (P<0...
December 2017: Experimental and Therapeutic Medicine
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