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cerebral hemodynamics

Jinge Yang, Dan Wu, Yong Tang, Huabei Jiang
Acupuncture has been an effective treatment for various pain in China for several thousand years. However, the mechanisms underlying this mysterious ancient healing are still largely unknown. Here we applied photoacoustic microscopy (PAM) to investigate brain hemodynamic changes in response to electronic acupuncture (EA) at ST36 (Zusanli). Due to the high optical absorption of blood at 532 nm, PAM could sensitively probe changes in hemoglobin concentration (HbT, i.e., cerebral blood volume [CBV]) of cortical regions in high resolution...
October 18, 2016: Journal of Biophotonics
Julien Pichette, Audrey Laurence, Leticia Angulo, Frederic Lesage, Alain Bouthillier, Dang Khoa Nguyen, Frederic Leblond
Using light, we are able to visualize the hemodynamic behavior of the brain to better understand neurovascular coupling and cerebral metabolism. In vivo optical imaging of tissue using endogenous chromophores necessitates spectroscopic detection to ensure molecular specificity as well as sufficiently high imaging speed and signal-to-noise ratio, to allow dynamic physiological changes to be captured, isolated, and used as surrogate of pathophysiological processes. An optical imaging system is introduced using a 16-bands on-chip hyperspectral camera...
October 2016: Neurophotonics
Leroy L Cooper, Gary F Mitchell
BACKGROUND: Aortic stiffness is associated with cardiovascular and cerebrovascular events and cognitive decline. This mini-review focuses on relations of aortic stiffness with microvascular dysfunction and discusses the contribution of abnormal pulsatile hemodynamics to cerebrovascular damage and cognitive decline. We also provide a rationale for considering aortic stiffness as a putative and important contributor to memory impairment in older individuals. SUMMARY: Aging is associated with stiffening of the aorta but not the muscular arteries, which reduces wave reflection and increases the transmission of pulsatility into the periphery...
September 2016: Pulse (Basel, Switzerland)
Jagdish C Mohan, Madhu Shukla, Vishwas Mohan, Arvind Sethi
Left atrial dissection is a very uncommon complication of cardiac surgery and usually causes significant hemodynamic compromise. Little is known about spontaneous dissection of the left atrium. Two patients, one middle-aged man and another elderly woman were evaluated following stroke. Routine trans-thoracic echocardiogram showed vertical division of the left atrium with both chambers communicating with each other through an orifice. Detailed trans-oesophageal echocardiographic study revealed dissection of the left atrium producing an additional false chamber (pseudo-aneurysm) placed posterior to the left atrial appendage and above the postero-lateral aspect of mitral annulus...
September 2016: Indian Heart Journal
Nolan S Hartkamp, Reinoud P H Bokkers, M J P van Osch, Gert J de Borst, Jeroen Hendrikse
BACKGROUND AND PURPOSE: To assess the effect of unilateral large vessel disease upon the cerebral hemodynamic autoregulatory status in the basal ganglia of patients with steno-occlusive internal carotid artery (ICA) disease. MATERIALS AND METHODS: Twenty-five healthy volunteers and 38 patients with a unilateral symptomatic steno-occlusive ICA lesion and were investigated; 20 with a stenosis >50% and 18 with an occlusion. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were assessed with pseudo-continuous arterial spin labeling (ASL) magnetic resonance (MR) imaging before and after administration of acetazolamide...
October 12, 2016: Journal of Neuroradiology. Journal de Neuroradiologie
Fuyou Liang, Xiaosheng Liu, Ryuhei Yamaguchi, Hao Liu
Recent studies raised increasing concern about the reliability of computer models in reproducing in vivo hemodynamics in cerebral aneurysms. Boundary condition problem is among the most frequently addressed issues since three-dimensional (3-D) modeling is usually restricted to local arterial segments. The present study focused on aneurysms on the anterior communicating artery (ACoA) which represent a large subgroup of detected cerebral aneurysms and, in particular, have a relatively high risk of rupture compared to aneurysms located in other regions...
October 6, 2016: Journal of Biomechanics
Yeongu Chung, Sung Ho Lee, Seok Keun Choi
BACKGROUND: Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass is associated with several surgical problems. Despite the vascular patency and hemodynamic changes after the anastomosis, wound problems can be a major surgical complication. METHODS: In a review of 41 surgical cases of STA-MCA bypass for moyamoya disease or cerebral occlusive vascular diseases, we compared the conventional ("Out-to-In") dissection method for STA (n=23) with the "In-to-Out" (ITO) dissection method (n=18) and evaluated the surgical results with respect to wound problems...
October 11, 2016: World Neurosurgery
Georgios Tsivgoulis, Andrei V Alexandrov
PURPOSE OF REVIEW: Low cost, avoidance of irradiation, and high temporal resolution are inherent advantages of ultrasound imaging that translate into multiple clinical uses in many domains of neurology. This article presents clinical uses of ultrasound examination in cerebrovascular, neurodegenerative, and peripheral nervous system diseases. RECENT FINDINGS: Modern treatment and prevention of ischemic stroke rely on prompt diagnosis. Ultrasonography has found a place as a noninvasive screening test and bedside technique that provides estimates of the degree of stenosis as well as hemodynamic and structural information about intracranial and extracranial vessels in real time...
October 2016: Continuum: Lifelong Learning in Neurology
Sarah E Bigby, Jennifer E Carter, Sébastien Bauquier, Thierry Beths
Anesthesia protocols for patients with intracranial lesions need to provide hemodynamic stability, preserve cerebrovascular autoregulation, avoid increases in intracranial pressure, and facilitate a rapid recovery. Propofol total intravenous anesthesia (TIVA) maintains cerebral blood flow autoregulation and is considered superior to inhalant agents as an anesthetic protocol for patients with intracranial lesions. A propofol-based TIVA subsequent to premedication with medetomidine and diazepam was used in a king penguin ( Aptenodytes patagonicus ) undergoing magnetic resonance imaging of the brain after a new onset of seizures...
September 2016: Journal of Avian Medicine and Surgery
E N D'yakonova, A I Fedin, V V Makerova, V N Gorbunov
AIM: To study the efficacy of L-lysine aescinat in the treatment of vascular and microvascular disorders in patients with cerebral venous dystonia. MATERIAL AND METHODS: Sixty-eight patients, 25 male and 43 female, aged from 25 to 56 years, with disturbances of venous cerebral blood circulation and venous outflow difficulties were examined. The examination included the assessment of cerebral hemodynamics using the algorithm of complex ultrasound examinations and functional status of the microcirculation by the laser Doppler flowmetry (LDF) at baseline and 10 days after treatment with L-lysine aescinat...
2016: Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova
Jonathan P Mynard, Remi Kowalski, Michael M H Cheung, Joseph J Smolich
Wave reflection from the site of aortic coarctation produces a reflected backward compression wave (BCW) that raises left ventricular (LV) afterload. However, not all reflected wave power will propagate back to the LV. This study investigated the hypothesis that the BCW is partially transmitted into supra-aortic vessels as a forward wave and explored the consequences of this phenomenon for cerebral and LV haemodynamic load. In eight sheep, high fidelity pressure and flow were measured in the aortic trunk (AoT) and brachiocephalic trunk (BCT, the single supra-aortic vessel present in sheep) at baseline and during two levels of proximal descending aortic constriction...
October 11, 2016: Biomechanics and Modeling in Mechanobiology
Mohamed Ghalayini, Pierre-Yves Brun, Pascal Augustin, Elise Guivarch, Marie Pierre Dilly, Sophie Provenchere, Pierre Mordant, Yves Castier, Philippe Montravers, Dan Longrois
Competitive flows syndrome result in severe regional hypoxemia when the deoxygenated flow from the native left ventricle (LV) competes with oxygenated flow from extracorporeal life support (ECLS) pump with potentially severe consequences for the cerebral and coronary circulations. Fast correction of hypoxemia could be obtained by decreasing native LV flow by infusion of a short-acting beta-blocker (esmolol). Our purpose was to retrospectively review the efficacy of esmolol in this situation and hypothesize on the potential mechanisms of action and the associated risks...
September 2016: Journal of Extra-corporeal Technology
Ronak Dholakia, Chandramouli Sadasivan, David Fiorella, Henry Woo, B Barry Lieber
Cerebral aneurysms are pathological focal evaginations of the arterial wall at and around the junctions of the circle of Willis. Their tenuous walls predispose aneurysms to leak or rupture leading to hemorrhagic strokes with high morbidity and mortality rates. The endovascular treatment of cerebral aneurysms currently includes the implantation of fine-mesh stents, called flow diverters, within the parent artery bearing the aneurysm. By mitigating flow velocities within the aneurysmal sac, the devices preferentially induce thrombus formation in the aneurysm within hours to days...
October 11, 2016: Journal of Biomechanical Engineering
Zhenhu Liang, Yue Gu, Xuejing Duan, Lei Cheng, Shujuan Liang, Yunjie Tong, Xiaoli Li
Monitoring the changes of cerebral hemodynamics and the state of consciousness during general anesthesia (GA) is clinically important. There is a great need for developing advanced detectors to investigate the physiological processes of the brain during GA. We developed a multichanneled, functional near-infrared spectroscopy (fNIRS) system device and applied it to GA operation monitoring. The cerebral hemodynamic data from the forehead of 11 patients undergoing propofol and sevoflurane anesthesia were analyzed...
October 2016: Neurophotonics
Mei-Ling Sharon Tai, Vijay K Sharma
BACKGROUND: Vascular complications are important causes of cerebral infarction in tuberculous meningitis (TBM).Transcranial Doppler ultrasonography (TCD) is a non-invasive tool that can provide real-time information about cerebral hemodynamics. However, the literature on the role of TCD in the diagnosis or monitoring of vasculopathy associated with TBM is scarce. We explored the role of TCD in the diagnosis and monitoring of TBM-related vasculopathy of the major intracranial arteries...
2016: PloS One
Stefano Bembich, Gabriele Cont, Jenny Bua, Chiara Orlando, Donatella Di Benedetto, Sergio Demarini
OBJECTIVE: By multichannel near-infrared spectroscopy, we studied if gestational age has any influence on preterm cerebral hemodynamics, during bolus feeding. METHODS: Oxy-haemoglobin (HbO2), as cerebral blood flow estimate, and the ratio between HbO2 and total haemoglobin (HbO2/HbTot), as cerebral oxygenation estimate, were assessed in 40 stable premature infants, during a 10 min bolus feeding. RESULTS: We found no effect of any of the gestational ages studied (25-34 weeks) either on cerebral blood flow or on oxygenation, during a bolus feeding procedure...
June 29, 2016: Journal of Maternal-fetal & Neonatal Medicine
Chubin Ou, Wei Huang, Matthew Ming-Fai Yuen, Yi Qian
Hemodynamics has been recognized as an important factor in the development, growth, and rupture of cerebral aneurysms, and investigated by computational fluid dynamics techniques using a single phase approach. However, flow-dependent cell transport and interactions are usually ignored in single phase models, in which blood is usually treated as a single phase Newtonian fluid. For getting better insight into the underlying pathology of intracranial aneurysm, cell transport and interactions should be covered in hemodynamic studies...
September 16, 2016: Journal of Biomechanics
Sophia F Shakur, Victor A Aletich, Sepideh Amin-Hanjani, Ahmed E Hussein, Fady T Charbel, Ali Alaraj
BACKGROUND: Pipeline embolization devices (PEDs) are commonly used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage. Although intra-aneurysmal hemodynamic changes have been studied, parent vessel and intracranial hemodynamics after PED use are unknown. We examine the impact of flow diversion on parent artery and distal intracranial hemodynamics. METHOD: Patients with internal carotid cerebral aneurysms treated with PED who had flow volume rate, flow velocities, pulsatility index, resistance index, Lindegaard ratio, and wall shear stress (WSS) obtained after treatment using quantitative magnetic resonance angiography were reviewed...
October 4, 2016: Interventional Neuroradiology
Jia Liu, Zhengzheng Yan, Yuehua Pu, Wen-Shin Shiu, Jianhuang Wu, Rongliang Chen, Xinyi Leng, Haiqiang Qin, Xin Liu, Baixue Jia, Ligang Song, Yilong Wang, Zhongrong Miao, Yongjun Wang, Liping Liu, Xiao-Chuan Cai
The fractional pressure ratio is introduced to quantitatively assess the hemodynamic significance of severe intracranial stenosis. A computational fluid dynamics-based method is proposed to non-invasively compute the FPRCFD and compared against fractional pressure ratio measured by an invasive technique. Eleven patients with severe intracranial stenosis considered for endovascular intervention were recruited and an invasive procedure was performed to measure the distal and the aortic pressure (Pd and Pa). The fractional pressure ratio was calculated as [Formula: see text] The computed tomography angiography was used to reconstruct three-dimensional (3D) arteries for each patient...
October 4, 2016: Journal of Cerebral Blood Flow and Metabolism
David R Busch, Craig G Rusin, Wanda Miller-Hance, Kathy Kibler, Wesley B Baker, Jeffrey S Heinle, Charles D Fraser, Arjun G Yodh, Daniel J Licht, Kenneth M Brady
While survival of children with complex congenital heart defects has improved in recent years, roughly half suffer neurological deficits suspected to be related to cerebral ischemia. Here we report the first demonstration of optical diffuse correlation spectroscopy (DCS) for continuous and non-invasive monitoring of cerebral microvascular blood flow during complex human neonatal or cardiac surgery. Comparison between DCS and Doppler ultrasound flow measurements during deep hypothermia, circulatory arrest, and rewarming were in good agreement...
September 1, 2016: Biomedical Optics Express
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