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Transcranial doppler

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https://www.readbyqxmd.com/read/28333037/cerebral-hemodynamic-with-intra-aortic-balloon-pump-business-as-usual
#1
Juliana Caldas, Ronney B Panerai, Edson Bor-Seng-Shu, Juliano Almeida, Graziela Ferreira, Ligia Cunha, Ricardo Nogueira, Marcelo Oliveira, Fabio Jatene, Thompson Robinson, Ludhmila Hajjar
Intra-aortic balloon pump (IABP) is commonly used as mechanical support after cardiac surgery or cardiac shock. Although its benefits for cardiac function have been well documented, its effects on cerebral circulation are still controversial. We hypothesized that transfer function analysis (TFA) and continuous estimates of dynamic cerebral autoregulation (CA) provide consistent results in the assessment of cerebral autoregulation in patients with IABP. Continuous recordings of blood pressure (BP, intra-arterial line), end-tidal CO2, heart rate and cerebral blood flow velocity (CBFV, transcranial Doppler) were obtained i) 5 minutes with IABP ratio 1:3, ii) 5 minutes, starting 1 minute with the IABP-ON, and continuing for another 4 minutes without pump assistance (IABP-OFF)...
March 23, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28322988/measurement-reliability-of-atypical-language-lateralisation-assessed-using-functional-transcranial-doppler-ultrasound
#2
Jessica C Hodgson, John M Hudson
It is well established that some individuals present with atypical, non-left hemisphere, cerebral lateralisation for language processing. However previous studies exploring the reliability of functional blood flow responses to detect lateralised activation during speech have focused only on individuals with typical left sided dominance. Here we report test-retest and between-task reliability measures obtained with functional transcranial Doppler ultrasound in 47 participants, including 9 with atypical language presentation...
March 16, 2017: Biological Psychology
https://www.readbyqxmd.com/read/28320115/reversible-cerebral-vasoconstriction-syndrome-in-puerperium-a-prospective-study
#3
Gian Paolo Anzola, Renato Brighenti, Milena Cobelli, Alessia Giossi, Sara Mazzucco, Silvia Olivato, Elisa Pari, Maria Paola Piras, Alessandro Padovani, Fabrizio Rinaldi, Giulia Turri
BACKGROUND AND AIM OF THE STUDY: Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by severe "thunderclap" headache, with or without associated neurological symptoms and neuroimaging findings of reversible vasoconstriction of cerebral arteries. Puerperium is a recognized precipitant, but the incidence of puerperal RCVS is unknown. We conducted a prospective study to assess incidence, risk factors and clinical features of RCVS. MATERIAL AND METHOD: Nine-hundred consecutive puerperae were prospectively enrolled within three days of delivery...
April 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28317214/characterization-of-blood-flow-through-intrapulmonary-arteriovenous-anastomoses-and-patent-foramen-ovale-at-rest-and-during-exercise-in-stroke-and-transient-ischemic-attack-patients
#4
Rinaldo Romac, Otto Barak, Duska Glavas, Zora Susilovic Grabovac, Petar Lozo, Igor Roje, Kresimir Caljkusic, Irena Drmic-Hofman, James T Davis, Zeljko Dujic, Andrew T Lovering
OBJECTIVES: We determined whether stroke and/or TIA subjects have exercise-induced blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) and/or patent foramen ovale (QPFO ) and a genetic predisposition for ischemic stroke. METHODS: Twenty-eight stroke and/or TIA subjects (33-63 years old) underwent transthoracic saline contrast echocardiography concomitant with transcranial Doppler to detect QIPAVA and QPFO at rest and during supine exercise with and without breathing 100% O2 ...
March 19, 2017: Echocardiography
https://www.readbyqxmd.com/read/28314626/cerebral-hemodynamic-effects-of-cheyne-stokes-respiration-in-a-patient-with-stroke
#5
R C Nogueira, R B Panerai, M J Teixeira, T G Robinson, E Bor-Seng-Shu
INTRODUCTION: Cheyne-Stokes respiration (CSR) and central sleep apnea (CSA) are common in patients with heart failure and/or stroke. We aim to describe the cerebrovascular effects of CSR during the acute phase of stroke in a heart failure patient. CASE REPORT: A 74-year-old male with previous dilated cardiomyopathy had sudden onset of right hemiparesis and aphasia. A transcranial Doppler was performed with continuous measurement of blood pressure (BP) (Finometer) and end-tidal CO2 (nasal capnography)...
March 14, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28304181/computed-tomography-angiography-as-a-confirmatory-test-for-the-diagnosis-of-brain-death
#6
Mark P Garrett, Richard W Williamson, Michael A Bohl, C Roger Bird, Nicholas Theodore
OBJECTIVE For a diagnosis of brain death (BD), ancillary testing is performed if patient factors prohibit a complete clinical examination and apnea test. The American Academy of Neurology (AAN) guidelines identify cerebral angiography (CA), cerebral scintigraphy, electroencephalography, and transcranial Doppler ultrasonography as accepted ancillary tests. CA is widely considered the gold standard of these, as it provides the most reliable assessment of intracranial blood flow. CT angiography (CTA) is a noninvasive and widely available study that is also capable of identifying absent or severely diminished intracranial blood flow, but it is not included among the AAN's accepted ancillary tests because of insufficient evidence demonstrating its reliability...
March 17, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28293809/a-mesenteric-traction-syndrome-affects-near-infrared-spectroscopy-evaluated-cerebral-oxygenation-because-skin-blood-flow-increases
#7
Niels D Olesen, Henrik Sørensen, Rikard Ambrus, Lars B Svendsen, Anton Lund, Niels H Secher
During abdominal surgery manipulation of internal organs may induce a "mesenteric traction syndrome" (MTS) including a triad of flushing, hypotension, and tachycardia that lasts for about 30 min. We evaluated whether MTS affects near-infrared spectroscopy (NIRS) assessed frontal lobe oxygenation (ScO2) by an increase in forehead skin blood flow (SkBF). The study intended to include 10 patients who developed MTS during pancreaticoduodenectomy and 22 patients were enrolled (age 61 ± 8 years; mean ± SD)...
March 14, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28291094/predictors-of-outcome-with-cerebral-autoregulation-monitoring-a-systematic-review-and-meta-analysis
#8
Lucia Rivera-Lara, Andres Zorrilla-Vaca, Romer Geocadin, Wendy Ziai, Ryan Healy, Richard Thompson, Peter Smielewski, Marek Czosnyka, Charles W Hogue
OBJECTIVE: To compare cerebral autoregulation indices as predictors of patient outcome and their dependence on duration of monitoring. DATA SOURCES: Systematic literature search and meta-analysis using PubMed, EMBASE, and the Cochrane Library from January 1990 to October 2015. STUDY SELECTION: We chose articles that assessed the association between cerebral autoregulation indices and dichotomized or continuous outcomes reported as standardized mean differences or correlation coefficients (R), respectively...
April 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28287758/cerebral-hemodynamics-during-scene-viewing-hemispheric-lateralization-predicts-temporal-gaze-behavior-associated-with-distinct-modes-of-visual-processing
#9
Mark Mills, Mohammed Alwatban, Benjamin Hage, Erin Barney, Edward J Truemper, Gregory R Bashford, Michael D Dodd
Systematic patterns of eye movements during scene perception suggest a functional distinction between 2 viewing modes: an ambient mode (characterized by short fixations and large saccades) thought to reflect dorsal activity involved with spatial analysis, and a focal mode (characterized by long fixations and small saccades) thought to reflect ventral activity involved with object analysis. Little neuroscientific evidence exists supporting this claim. Here, functional transcranial Doppler ultrasound (fTCD) was used to investigate whether these modes show hemispheric specialization...
March 13, 2017: Journal of Experimental Psychology. Human Perception and Performance
https://www.readbyqxmd.com/read/28287282/cerebrovascular-reactivity-in-acute-hyperoxia-in-patients-with-acute-ischaemic-stroke
#10
Ivana Hegeduš, Jakov Milić, Anita Ćosić, Krunoslav Buljan, Ines Drenjančević
AIM: This study aimed to assess the effect of acute hyperoxia on cerebral and systemic heamodynamics and the plasma concentration of prostacyclin and thromboxane in patients with stroke. METHODS: Mean blood flow velocity (MBFV), pulsatility and resistance indices of the middle cerebral artery using transcranial Doppler ultrasound before and during acute hyperoxia (4 L of 100%O2/15' over facial mask) in 92 participants - 25 patients with acute ischaemic stroke (AIS) that occurred within 72 hours and diabetes mellitus (SPDM), 26 AIS patients without DM (SP) and in 41 healthy controls (HS), were measured...
March 13, 2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/28281739/cerebral-micro-embolization-during-pulmonary-vein-isolation-relation-to-post-ablation-silent-cerebral-ischemia
#11
Edina Nagy-Baló, Mihran Martirosyan, Gábor Sándorfi, Orsolya Hajas, Levente Lánczi, Ervin Berényi, Lilla Ladányi, Alexandra Kiss, István Édes, Zoltán Csanádi
BACKGROUND: High incidences of silent cerebral ischemia (SCI) have been revealed by diffusion-weighted magnetic resonance imaging (DW MRI) after pulmonary vein isolation (PVI) for atrial fibrillation. A high number of mostly gaseous micro-embolic signals (MESs) was detected by transcranial Doppler (TCD) during PVI. In this investigation the possible relationship between MESs detected intraoperatively by TCD and new SCI on DW MRI post-ablation is reported. METHODS: 27 consecutive atrial fibrillation patients (6 female, age median: 64 interquartile range: 13...
March 10, 2017: Cardiology Journal
https://www.readbyqxmd.com/read/28279885/brain-morphometric-analysis-predicts-decline-of-intelligence-quotient-in-children-with-sickle-cell-disease-a-preliminary-study
#12
Rong Chen, Jaroslaw Krejza, Michal Arkuszewski, Robert A Zimmerman, Edward H Herskovits, Elias R Melhem
PURPOSE: For children with sickle cell disease (SCD) and at low risk category of stroke, we aim to build a predictive model to differentiate those with decline of intelligence-quotient (IQ) from counterparts without decline, based on structural magnetic-resonance (MR) imaging volumetric analysis. MATERIALS AND METHODS: This preliminary prospective cohort study included 25 children with SCD, homozygous for hemoglobin S, with no history of stroke and transcranial Doppler mean velocities below 170cm/s at baseline...
March 6, 2017: Advances in Medical Sciences
https://www.readbyqxmd.com/read/28269120/automated-embolic-signal-detection-using-adaptive-gain-control-and-classification-using-anfis
#13
Praotasna Sombune, Phongphan Phienphanich, Sombat Muengtaweepongsa, Anuchit Ruamthanthong, Charturong Tantibundhit
This work proposes an automated system for real-time high-accuracy detection of cerebral embolic signals (ES) to couple with transcranial Doppler ultrasound (TCD) devices in diagnosing a risk of stroke. The algorithm employs Adaptive Gain Control (AGC) approach to capture suspected ESs in real-time. Then, Adaptive Wavelet Packet Transform (AWPT) and Fast Fourier Transform (FFT) are used to extract from them features most efficiently representing ES, which determined by Sequential Feature Selection technique...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269071/pre-clinical-investigations-of-multi-path-propagation-in-transcranial-doppler-ultrasound-flow-phantom
#14
Alexander J Weir, Cheng-Xiang Wang, Stuart Parks
There are various practical situations in medical applications when pre-clinical investigations must be performed using a simulation environment or test bench prior to human studies. One example is the analysis of propagation channels in Transcanial Doppler (TCD) ultrasound (US), a signal processing challenge requiring the analysis of data from US waves scattered in three dimensions (3D). When examining the effects of scatterers in such channels, it is common to use a data acquisition test bench and a Doppler flow phantom...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268789/perspective-imaging-of-flow-in-arterial-model-obtained-with-continuous-wave-doppler-focusing-technique
#15
Ryo Nagaoka, Katsuhiro Sasaki, Seiichi Zama, Masaaki Nagone, Hiroshi Nagai, Yasuhito Takeuchi, Yoshifumi Saijo
Flowing emboli in the circulatory system cause fatal diseases such as stroke or pulmonary embolism. Conventional transcranial Doppler ultrasound for detection of emboli requires precise positioning by experienced examiner. In the present study, an easier emboli detection device by visualizing perspective view of blood vessel is proposed. The perspective image was obtained with continuous wave (CW) Doppler ultrasound from 2-dimensional array probe. CW Doppler signal from each element was focused by novel beam forming algorithm to obtain en face images at arbitrary depth to form perspective image...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268070/post-carotid-endarterectomy-hypertension-part-1-association-with-pre-operative-clinical-imaging-and-physiological-parameters
#16
J E Newman, M J Bown, R D Sayers, J P Thompson, T G Robinson, B Williams, R Panerai, P Lacy, A R Naylor
OBJECTIVE/BACKGROUND: Post-endarterectomy hypertension (PEH) is a well recognised, but poorly understood, phenomenon after carotid endarterectomy (CEA) that is associated with post-operative intracranial haemorrhage, hyperperfusion syndrome, and cardiac complications. The aim of the current study was to identify pre-operative clinical, imaging, and physiological parameters associated with PEH. METHODS: In total, 106 CEA patients undergoing CEA under general anaesthesia underwent pre-operative evaluation of 24 hour ambulatory arterial blood pressure (BP), baroreceptor sensitivity, cerebral autoregulation, and transcranial Doppler measurement of cerebral blood flow velocity (CBFv) and pulsatility index...
March 3, 2017: European Journal of Vascular and Endovascular Surgery
https://www.readbyqxmd.com/read/28262564/is-dynamic-cerebral-autoregulation-bilaterally-impaired-after-unilateral-acute-ischemic-stroke
#17
Li Xiong, Ge Tian, Wenhua Lin, Wei Wang, Lijuan Wang, Thomas Leung, Vincent Mok, Jia Liu, Xiangyan Chen, Ka Sing Wong
OBJECTIVE: Whether dynamic cerebral autoregulation (dCA) is impaired focally in the affected hemisphere or bilaterally in both the affected and nonaffected hemispheres after ischemic stroke remains controversial. We therefore investigated the pattern of dCA in acute ischemic stroke patients with different subtypes. METHODS: Sixty acute ischemic stroke patients with unilateral anterior circulation infarct [30 with large artery atherosclerosis (LAA), 13 with small vessel disease (SVD), and 17 with coexisting LAA and SVD] and 16 healthy controls were enrolled...
March 3, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28262007/muscle-oxygen-saturation-increases-during-head-up-tilt-induced-pre-syncope
#18
A Lund, H Sørensen, T W Jensen, M J Niemann, N D Olesen, H B Nielsen, N V Olsen, N H Secher
AIM: To evaluate whether muscle vasodilatation plays a role for hypotension developed during central hypovolaemia, muscle oxygenation (Sm O2 ) was examined during (pre)syncope induced by head-up tilt (HUT). Skin blood flow (SkBF) and oxygenation (Sskin O2 ) were determined because evaluation of Sm O2 may be affected by superficial tissue oxygenation. Furthermore, we evaluated cerebral oxygenation (Sc O2 ) and middle cerebral artery mean blood flow velocity (MCAvmean ). METHODS: Twenty healthy male volunteers (median age 24 years; range 19-38) were subjected to passive 50° HUT for 1 hour or until (pre)syncope...
March 6, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28261153/non-invasive-respiratory-impedance-enhances-cerebral-perfusion-in-healthy-adults
#19
Christopher G Favilla, Ashwin B Parthasarathy, John A Detre, Arjun G Yodh, Michael T Mullen, Scott E Kasner, Kimberly Gannon, Steven R Messé
Optimization of cerebral blood flow (CBF) is the cornerstone of clinical management in a number of neurologic diseases, most notably ischemic stroke. Intrathoracic pressure influences cardiac output and has the potential to impact CBF. Here, we aim to quantify cerebral hemodynamic changes in response to increased respiratory impedance (RI) using a non-invasive respiratory device. We measured cerebral perfusion under varying levels of RI (6 cm H2O, 9 cm H2O, and 12 cm H2O) in 20 healthy volunteers. Simultaneous measurements of microvascular CBF and middle cerebral artery mean flow velocity (MFV), respectively, were performed with optical diffuse correlation spectroscopy and transcranial Doppler ultrasound...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28258058/impact-of-mild-orthostatic-stress-on-aortic-cerebral-hemodynamic-transmission-insight-from-the-frequency-domain
#20
Jun Sugawara, Tsubasa Tomoto, Tomoko Imai, Seiji Maeda, Shigehiko Ogoh
High cerebral pressure and flow fluctuations could be a risk for future cerebrovascular disease. This study aims to determine whether acute systemic vasoconstriction affects the dynamic pulsatile hemodynamic transmission from the aorta to the brain. We applied a stepwise lower body negative pressure (LBNP) (-10, -20, and -30 mmHg) in 15 young men to induce systemic vasoconstriction. To elucidate the dynamic relationship between the changes in aortic pressure (AoP, estimated from the radial arterial pressure waveforms) and the cerebral blood flow velocity (CBFV) at the middle cerebral artery (via a transcranial Doppler), frequency-domain analysis characterized the beat-to-beat slow oscillation (0...
March 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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