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Cerebral hemodynamic

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https://www.readbyqxmd.com/read/28086807/detection-of-critical-cerebral-desaturation-thresholds-by-three-regional-oximeters-during-hypoxia-a-pilot-study-in-healthy-volunteers
#1
Kerry L Tomlin, Anna-Maria Neitenbach, Ulf Borg
BACKGROUND: Regional oximetry is increasingly used to monitor post-extraction oxygen status of the brain during surgical procedures where hemodynamic fluctuations are expected. Particularly in cardiac surgery, clinicians employ an interventional algorithm to restore baseline regional oxygen saturation (rSO2) when a patient reaches a critical desaturation threshold. Evidence suggests that monitoring cardiac surgery patients and intervening to maintain rSO2 can improve postoperative outcomes; however, evidence generated with one manufacturer's device may not be applicable to others...
January 13, 2017: BMC Anesthesiology
https://www.readbyqxmd.com/read/28072724/fatal-antiphospholipid-syndrome-following-endoscopic-transnasal-transsphenoidal-surgery-for-a-pituitary-tumor-a-case-report
#2
Chiao-Zhu Li, Chiao-Ching Li, Chih-Chuan Hsieh, Meng-Chi Lin, Dueng-Yuan Hueng, Feng-Chen Liu, Yuan-Hao Chen
INTRODUCTION: The fatal type of antiphospholipid syndrome is a rare but life-threating condition. It may be triggered by surgery or infection. Endoscopic transnasal-transsphenoidal surgery is a common procedure for pituitary tumor. We report a catastrophic case of a young woman died of fatal antiphospholipid syndrome following endoscopic transnasal-transsphenoidal surgery. METHODS AND RESULT: A 31-year-old woman of a history of stroke received endoscopic transnasal-transsphenoidal surgery for a pituitary tumor...
January 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28069927/impact-of-altered-cholinergic-tones-on-the-neurovascular-coupling-response-to-whisker-stimulation
#3
Clotilde Lecrux, Claire H Sandoe, Sujaya Neupane, Pascal Kropf, Xavier Toussay, Xin-Kang Tong, María Lacalle-Aurioles, Amir Shmuel, Edith Hamel
Brain imaging techniques that use vascular signals to map changes in neuronal activity rely on the coupling between electrophysiology and hemodynamics, a phenomenon referred to "neurovascular coupling" (NVC). It is unknown whether this relationship remains reliable under altered brain states associated to acetylcholine (ACh) levels, such as attention and arousal, and in pathological conditions like Alzheimer's disease. We therefore assessed the effects of varying ACh tone on whisker evoked-NVC responses in rat barrel cortex, measured by cerebral blood flow (CBF) and neurophysiological recordings (local field potentials, LFPs)...
January 9, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28067615/intracranial-atherosclerosis-from-anatomy-to-pathophysiology
#4
Yuehua Pu, Linfang Lan, Xinyi Leng, Lawrence Ks Wong, Liping Liu
Background Intracranial atherosclerotic stenosis is an important etiology subtype of ischemic stroke. Stenosis severity was thought to be the main reference index for clinical treatment and research. However, stenosis could not reflect the ischemia risk completely, instead the hemodynamic state across the lesion, the extent of collateral circulation, and perfusion impairment downstream the stenosis are more important. Aims We write this review aimed to summarize novel angiographic methods applied in the evaluation of functional severity of ICAS, and commented on their limitations and prospects in future research...
January 1, 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28061497/cerebellar-hemorrhage-due-to-a-direct-carotid-cavernous-fistula-after-surgery-for-maxillary-cancer
#5
Yoshinobu Kamio, Hisaya Hiramatsu, Mika Kamiya, Shuhei Yamashita, Hiroki Namba
Infratentorial cerebral hemorrhage due to a direct carotid-cavernous fistula (CCF) is very rare. To our knowledge, only four such cases have been reported. Cerebellar hemorrhage due to a direct CCF has not been reported. We describe a 63-year-old female who presented with reduced consciousness 3 days after undergoing a maxillectomy for maxillary cancer. Computed tomography showed a cerebellar hemorrhage. Magnetic resonance angiography showed a left-sided direct CCF draining into the left petrosal and cerebellar veins through the left superior petrosal sinus (SPS)...
January 1, 2017: Journal of Korean Neurosurgical Society
https://www.readbyqxmd.com/read/28060546/gray-matter-hypertrophy-and-thickening-with-obstructive-sleep-apnea-in-middle-aged-and-older-adults
#6
Andrée-Ann Baril, Katia Gagnon, Pauline Brayet, Jacques Montplaisir, Louis De Beaumont, Julie Carrier, Chantal Lafond, Francis L'Heureux, Jean-François Gagnon, Nadia Gosselin
RATIONALE: Obstructive sleep apnea causes intermittent hypoxemia, hemodynamic fluctuations, and sleep fragmentation, all of which could damage cerebral gray matter that can be indirectly assessed with neuroimaging. OBJECTIVES: To investigate whether markers of obstructive sleep apnea severity are associated with gray matter changes among middle-aged and older individuals. METHODS: Seventy-one subjects (ages: 55 to 76; apnea-hypopnea index: 0...
January 6, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28059661/intravenous-infusion-of-mesenchymal-stem-cells-inhibits-intracranial-hemorrhage-after-recombinant-tissue-plasminogen-activator-therapy-for-transient-middle-cerebral-artery-occlusion-in-rats
#7
Masahito Nakazaki, Masanori Sasaki, Yuko Kataoka-Sasaki, Shinichi Oka, Takahiro Namioka, Ai Namioka, Rie Onodera, Junpei Suzuki, Yuichi Sasaki, Hiroshi Nagahama, Takeshi Mikami, Masahiko Wanibuchi, Jeffery D Kocsis, Osamu Honmou
OBJECTIVE Reperfusion therapy with intravenous recombinant tissue plasminogen activator (rtPA) is the standard of care for acute ischemic stroke. However, hemorrhagic complications can result. Intravenous infusion of mesenchymal stem cells (MSCs) reduces stroke volume and improves behavioral function in experimental stroke models. One suggested therapeutic mechanism is inhibition of vascular endothelial dysfunction. The objective of this study was to determine whether MSCs suppress hemorrhagic events after rtPA therapy in the acute phase of transient middle cerebral artery occlusion (tMCAO) in rats...
January 6, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28058473/brain-oxygenation-during-thoracoscopic-repair-of-long-gap-esophageal-atresia
#8
Lisanne J Stolwijk, David C van der Zee, Stefaan Tytgat, Desiree van der Werff, Manon J N L Benders, Maud Y A van Herwaarden, Petra M A Lemmers
BACKGROUND: Elongation and repair of long gap esophageal atresia (LGEA) can be performed thoracoscopically, even directly after birth. The effect of thoracoscopic CO2-insufflation on cerebral oxygenation (rScO2) during the consecutive thoracoscopic procedures in repair of LGEA was evaluated. METHODS: Prospective case series of five infants, with in total 16 repetitive thoracoscopic procedures. A CO2-pneumothorax was installed with a pressure of maximum 5 mmHg and flow of 1 L/min...
January 5, 2017: World Journal of Surgery
https://www.readbyqxmd.com/read/28057635/in-vivo-assessment-of-the-impact-of-regional-intracranial-atherosclerotic-lesions-on-brain-arterial-3d-hemodynamics
#9
C Wu, S Schnell, P Vakil, A R Honarmand, S A Ansari, J Carr, M Markl, S Prabhakaran
BACKGROUND AND PURPOSE: Intracranial atherosclerosis induces hemodynamic disturbance, which is not well-characterized, particularly in cerebral flow redistribution. We aimed to characterize the impact of regional stenotic lesions on intracranial hemodynamics by using 4D flow MR imaging. MATERIALS AND METHODS: 4D flow MR imaging was performed in 22 symptomatic patients (mean age, 68.4 ± 14.2 years) with intracranial stenosis (ICA, n = 7; MCA, n = 9; basilar artery, n = 6) and 10 age-appropriate healthy volunteers (mean age, 60...
January 5, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28056813/hemodynamic-effects-of-intraoperative-anesthetics-administration-in-photothrombotic-stroke-model-a-study-using-laser-speckle-imaging
#10
Hongyang Lu, Yao Li, Bin Bo, Lu Yuan, Xiaodan Lu, Hangdao Li, Shanbao Tong
BACKGROUND: Previous neuroimaging studies have shown the hemodynamic effect of either preconditioning or postconditioning anesthesia in ischemic stroke model. However, the anesthetic effect in hemodynamics during and immediately after the stroke modeling surgery remains unknown due to the lack of appropriate anesthesia-free stroke model and intraoperative imaging technology. In the present study, we utilized our recently developed photothrombotic model of focal cerebral ischemia in conscious and freely moving rats, and investigated transient hemodynamic changes with or without isoflurane administration...
January 5, 2017: BMC Neuroscience
https://www.readbyqxmd.com/read/28056454/collar-sign-in-incompletely-occluded-aneurysms-after-pipeline-embolization-evaluation-with-angiography-and-optical-coherence-tomography
#11
C J Griessenauer, R Gupta, S Shi, A Alturki, R Motiei-Langroudi, N Adeeb, C S Ogilvy, A J Thomas
BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device has emerged as an attractive treatment for cerebral aneurysms. Processes involved in aneurysm occlusion include changes in intra-aneurysmal hemodynamics and endothelialization of the device. Here, we call attention to a radiographic sign not previously reported that is detected in incompletely occluded aneurysms after treatment with the Pipeline Embolization Device at angiographic follow-up and referred to as the "collar sign...
November 10, 2016: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28052565/cerebral-hemodynamics-and-pseudo-continuous-arterial-spin-labeling-considerations-in-adults-with-sickle-cell-anemia
#12
Meher R Juttukonda, Lori C Jordan, Melissa C Gindville, Larry T Davis, Jennifer M Watchmaker, Sumit Pruthi, Manus J Donahue
Sickle cell anemia (SCA) is a genetic disorder resulting in reduced oxygen carrying capacity and elevated stroke risk. Pseudo-continuous arterial spin labeling (pCASL) measures of cerebral blood flow (CBF) may have relevance for stroke risk assessment; however, the effects of elevated flow velocity and reduced bolus arrival time (BAT) on CBF quantification in SCA patients have not been thoroughly characterized, and pCASL model parameters used in healthy adults are often applied to patients with SCA. Here, cervical arterial flow velocities and pCASL labeling efficiencies were computed in adults with SCA (n = 19) and age- and race-matched controls without sickle trait (n = 7) using pCASL in sequence with phase contrast MR angiography (MRA)...
January 4, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28046770/su-g-iep1-12-size-selective-arterial-cerebral-blood-volume-mapping-using-multiple-inversion-time-arterial-spin-labeling
#13
Y Jung, M Johnston, H Liu, C Whitlow
PURPOSE: To demonstrate the feasibility of a novel method for size specific arterial cerebral blood volume (aCBV) mapping using pseudo-continuous arterial spin labeling (PCASL), with multiple TI. METHODS: Multiple PCASL images were obtained from a subject with TI of [300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000] ms. Each TI pair was averaged six times. Two scans were performed: one without a flow crusher gradient and the other with a crusher gradient (10cm/s in three directions) to remove signals from large arteries...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28045242/evidence-for-periprocedural-antiplatelet-therapy-heparinization-and-bridging-of-coumarin-therapy-in-carotid-revascularization
#14
Art Brand, Gert J DE Borst
Thromboembolism prevention is a crucial factor determining both the natural outcome and outcome of intervention of stenotic atherosclerotic carotid artery pathology. Roughly 80% of all natural course cerebral ischemic events are caused by thromboembolism, versus 20% due to hemodynamic insufficiency. The risk of periprocedural cerebral (micro) thromboembolization during carotid revascularization is considered to be even higher, with a higher rate in carotid artery stenting (CAS) as compared to carotid endarterectomy (CEA)...
January 3, 2017: Journal of Cardiovascular Surgery
https://www.readbyqxmd.com/read/28041979/a-three-dimensional-single-scan-approach-for-the-measurement-of-changes-in-cerebral-blood-volume-blood-flow-and-blood-oxygenation-weighted-signals-during-functional-stimulation
#15
Ying Cheng, Qin Qin, Peter C M van Zijl, James J Pekar, Jun Hua
The blood-oxygenation-level-dependent (BOLD) effect reflects ensemble changes in several physiological parameters such as cerebral blood volume (CBV), blood flow (CBF), and cerebral metabolic rate of oxygen (CMRO2). Quantitative BOLD approaches have been developed to estimate CMRO2 dynamics from BOLD, CBF and CBV responses, generally using separate scans. The ability to detect changes in these parameters in a single scan would shorten the total scan time and reduce temporal variations in physiology or neuronal responses...
December 29, 2016: NeuroImage
https://www.readbyqxmd.com/read/28040435/in-vitro-investigation-of-the-hemodynamic-responses-of-the-cerebral-coronary-and-renal-circulations-with-a-rotary-blood-pump-installed-in-the-descending-aorta
#16
M A Rezaienia, G Paul, E J Avital, S Mozafari, M Rothman, T Korakianitis
This study investigates the hemodynamic responses of the cardiovascular system when a rotary blood pump is operating in the descending aorta, with a focus on the cerebral, coronary and renal autoregulation, using our in-house cardiovascular emulator. Several improvements have been made from our previous studies. A novel coronary system was developed to replicate the native coronary perfusion. Three pinch valves actuated by stepper motors were used to simulate the regional autoregulation systems of the native cerebral, coronary and renal circulations...
December 28, 2016: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28038898/demographic-and-systemic-hemodynamic-influences-in-mechanisms-of-cerebrovascular-regulation-in-healthy-adults
#17
João Madureira, Pedro Castro, Elsa Azevedo
OBJECTIVES: A competent cerebrovascular regulation maintains an adequate cerebral blood flow by 3 major mechanisms: cerebral autoregulation (CA), vasomotor reactivity (VMR), namely to CO2, and neurovascular coupling (NVC). However, most studies generalize their results based on a response to a single parameter. Using a full battery of neurovascular stress tests, our study aims to evaluate the relationships among grades of CA, VMR, and NVC, and how their interplay is influenced by demographic and systemic hemodynamic factors...
December 27, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28031998/different-mechanosensory-stimulations-of-the-lower-back-elicit-specific-changes-in-hemodynamics-and-oxygenation-in-cortical-sensorimotor-areas-a-fnirs-study
#18
Andrea Vrana, Michael L Meier, Sabina Hotz-Boendermaker, Barry K Humphreys, Felix Scholkmann
BACKGROUND AND OBJECTIVES: This study aimed at investigating the feasibility of functional near-infrared spectroscopy (fNIRS) to measure changes in cerebral hemodynamics and oxygenation evoked by painful and nonpainful mechanosensory stimulation on the lower back. The main objectives were to investigate whether cortical activity can be (1) detected using functional fNIRS, and (2) if it is possible to distinguish between painful and nonpainful pressure as well as a tactile brushing stimulus based on relative changes in oxy- and deoxyhemoglobin ([O2Hb] and [HHb])...
December 2016: Brain and Behavior
https://www.readbyqxmd.com/read/28030440/subclinical-bioprosthetic-aortic-valve-thrombosis-clinical-and-translational-implications
#19
Bobby Yanagawa, Amine Mazine, Deepak L Bhatt, Marie-Annick Clavel, Nancy Côté, Asim N Cheema, Philippe Pibarot, Subodh Verma
PURPOSE OF REVIEW: A recently published study has alerted the cardiovascular community to the existence of a significant and previously unrecognized risk of subclinical valve thrombosis following implantation of surgical and catheter-based bioprosthetic valves. The purpose of this article is to review our current understanding of this new clinical entity and to identify unanswered questions and areas for future research. RECENT FINDINGS: Subclinical bioprosthetic valve thrombosis (BPVT) is a more common phenomenon than previously appreciated...
December 24, 2016: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/28029271/hemodynamic-mechanisms-underlying-elevated-oxygen-extraction-fraction-oef-in-moyamoya-and-sickle-cell-anemia-patients
#20
Jennifer M Watchmaker, Meher R Juttukonda, Larry T Davis, Allison O Scott, Carlos C Faraco, Melissa C Gindville, Lori C Jordan, Petrice M Cogswell, Angela L Jefferson, Howard S Kirshner, Manus J Donahue
Moyamoya is a bilateral, complex cerebrovascular condition characterized by progressive non-atherosclerotic intracranial stenosis and collateral vessel formation. Moyamoya treatment focuses on restoring cerebral blood flow (CBF) through surgical revascularization, however stratifying patients for revascularization requires abilities to quantify how well parenchyma is compensating for arterial steno-occlusion. Globally elevated oxygen extraction fraction (OEF) secondary to CBF reduction may serve as a biomarker for tissue health in moyamoya patients, as suggested in patients with sickle cell anemia (SCA) and reduced oxygen carrying capacity...
January 1, 2016: Journal of Cerebral Blood Flow and Metabolism
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