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Blood Oxygenation Level Dependent

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https://www.readbyqxmd.com/read/28737596/creating-a-controlled-arterio-venous-shunt-by-reversing-the-extracorporeal-membrane-oxygenation-blood-flow-a-strategy-for-weaning-patients-off-veno-arterial-extracorporeal-membrane-oxygenation
#1
Christian Adrian Mattke, Emma Haisz, Nischal Pandya, Anthony Black, Prem Venugopal
OBJECTIVES: To assess whether reversing the veno-arterial extracorporeal membrane oxygenation blood flow (thereby creating a controlled arterio-venous shunt) can be used to wean children off extracorporeal membrane oxygenation. The standard practice for weaning patients off VA extracorporeal membrane oxygenation is to gradually reduce the blood flows delivered through the extracorporeal membrane oxygenation pump to a minimum level followed by either insertion of an "arterio-venous bridge" and clamping of the blood flow to the patient or direct decannulation...
July 21, 2017: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/28736924/evaluation-of-spiral-acquisition-variants-for-functional-imaging-of-human-superior-colliculus-at-3t-field-strength
#2
Vimal Singh, Josef Pfeuffer, Tiejun Zhao, David Ress
PURPOSE: High-resolution functional magnetic resonance imaging of human subcortical brain structures is challenging because of their deep location in the cranium, and their comparatively weak blood oxygen level dependent responses to strong stimuli. Magnetic resonance imaging data for subcortical brain regions exhibit both low signal-to-noise ratio and low functional contrast-to-noise ratio. To overcome these challenges, this work evaluates the use of dual-echo spiral variants that combine outward and inward trajectories...
July 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28736310/non-bold-contrast-for-laminar-fmri-in-humans-cbf-cbv-and-cmr02
#3
REVIEW
Laurentius Huber, Kâmil Uludağ, Harald E Möller
Functional magnetic resonance imaging (fMRI) using the blood oxygenation level-dependent (BOLD) contrast indirectly probes neuronal activity changes via evoked cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMR02) changes. The gradient-echo BOLD signal is mostly sensitive to ascending veins in the tissue and to pial veins. Thereby, the achievable spatial specificity to neuronal activation is limited. Furthermore, the non-linear interaction of CBF, CBV and CMR02 can hamper quantitative interpretations of the BOLD signal across cortical depths with different baseline physiology...
July 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28734059/localized-reductions-in-resting-state-functional-connectivity-in-children-with-prenatal-alcohol-exposure
#4
Jia Fan, Paul A Taylor, Sandra W Jacobson, Christopher D Molteno, Suril Gohel, Bharat B Biswal, Joseph L Jacobson, Ernesta M Meintjes
Fetal alcohol spectrum disorders (FASD) are characterized by impairment in cognitive function that may or may not be accompanied by craniofacial anomalies, microcephaly, and/or growth retardation. Resting-state functional MRI (rs-fMRI), which examines the low-frequency component of the blood oxygen level dependent (BOLD) signal in the absence of an explicit task, provides an efficient and powerful mechanism for studying functional brain networks even in low-functioning and young subjects. Studies using independent component analysis (ICA) have identified a set of resting-state networks (RSNs) that have been linked to distinct domains of cognitive and perceptual function, which are believed to reflect the intrinsic functional architecture of the brain...
July 22, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28733682/modulation-of-water-diffusion-by-activation-induced-neural-cell-swelling-in-aplysia-californica
#5
Yoshifumi Abe, Khieu Van Nguyen, Tomokazu Tsurugizawa, Luisa Ciobanu, Denis Le Bihan
Diffusion functional magnetic resonance imaging (DfMRI) has been proposed as a method for functional neuroimaging studies, as an alternative to blood oxygenation level dependent (BOLD)-fMRI. DfMRI is thought to more directly reflect neural activation, but its exact mechanism remains unclear. It has been hypothesized that the water apparent diffusion coefficient (ADC) decrease observed upon neural activation results from swelling of neurons or neuron parts. To elucidate the origin of the DfMRI response at cellular level we performed diffusion MR microscopy at 17...
July 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28730273/glucose-as-a-stimulation-agent-in-the-bold-functional-magnetic-resonance-imaging-for-liver-cirrhosis-and-hepatocellular-carcinoma-a-feasibility-study
#6
Fang Yuan, Bin Song, Zixing Huang, Xijiao Liu, Chunchao Xia
PURPOSE: To explore the role of glucose as a stimulation agent in the blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) for liver cirrhosis and hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty HCC patients with cirrhosis and 10 healthy volunteers were recruited. BOLD fMRI was performed for all participants prior to and 30 min after oral administration of glucose to measure the T2* values of normal liver parenchyma, HCC liver parenchyma, HCC center, and HCC edge...
July 20, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28729926/coherence-of-bold-signal-and-electrical-activity-in-the-human-brain-during-deep-sevoflurane-anesthesia
#7
Daniel Golkowski, Andreas Ranft, Tobias Kiel, Valentin Riedl, Philipp Kohl, Guido Rohrer, Joachim Pientka, Sebastian Berger, Christine Preibisch, Claus Zimmer, George A Mashour, Gerhard Schneider, Eberhard F Kochs, Rüdiger Ilg, Denis Jordan
INTRODUCTION: Changes in neural activity induce changes in functional magnetic resonance (fMRI) blood oxygenation level dependent (BOLD) signal. Commonly, increases in BOLD signal are ascribed to cellular excitation. OBJECTIVE: The relationship between electrical activity and BOLD signal in the human brain was probed on the basis of burst suppression EEG. This condition includes two distinct states of high and low electrical activity. METHODS: Resting-state simultaneous EEG and BOLD measurements were acquired during deep sevoflurane anesthesia with burst suppression EEG in nineteen healthy volunteers...
July 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28729830/resting-state-fluctuations-of-eeg-sensorimotor-rhythm-reflect-bold-activities-in-the-pericentral-areas-a-simultaneous-eeg-fmri-study
#8
Shohei Tsuchimoto, Shuka Shibusawa, Nobuaki Mizuguchi, Kenji Kato, Hiroki Ebata, Meigen Liu, Takashi Hanakawa, Junichi Ushiba
Blockade of the scalp electroencephalographic (EEG) sensorimotor rhythm (SMR) is a well-known phenomenon following attempted or executed motor functions. Such a frequency-specific power attenuation of the SMR occurs in the alpha and beta frequency bands and is spatially registered at primary somatosensory and motor cortices. Here, we hypothesized that resting-state fluctuations of the SMR in the alpha and beta frequency bands also covary with resting-state sensorimotor cortical activity, without involving task-related neural dynamics...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28729387/leg-blood-flow-is-impaired-during-small-muscle-mass-exercise-in-copd-patients
#9
Ulrik Winning Iepsen, Gregers Druedal Wibe Munch, Mette Rugbjerg, Camilla Koch Ryrsø, Niels Secher, Ylva Hellsten, Peter Lange, Bente Klarlund Pedersen, Pia Thaning, Stefan P Mortensen
Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with COPD. We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee-extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex matched healthy controls were studied...
July 20, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28729160/echo-time-dependence-of-the-bold-response-transients-a-window-into-brain-functional-physiology
#10
Martin Havlicek, Dimo Ivanov, Benedikt A Poser, Kamil Uludag
The blood oxygenation level-dependent (BOLD) fMRI response to neuronal activation results from a complex interplay of induced metabolic and vascular changes. Thus, its transients, such as initial overshoot and post-stimulus undershoot, provide a window into the dynamic relationships of the underlying physiological variables. In this study, we propose multi-echo fMRI as a tool to investigate the physiological underpinnings of the BOLD signal, in particular, and brain functional physiology, in general. In the human visual cortex at 3 T, we observed that the BOLD response is nonlinearly dependent on echo-time (TE) and the amount of nonlinearity varies during the entire time-course...
July 17, 2017: NeuroImage
https://www.readbyqxmd.com/read/28729016/learning-based-structurally-guided-construction-of-resting-state-functional-correlation-tensors
#11
Lichi Zhang, Han Zhang, Xiaobo Chen, Qian Wang, Pew-Thian Yap, Dinggang Shen
Functional magnetic resonance imaging (fMRI) measures changes in blood-oxygenation-level-dependent (BOLD) signals to detect brain activities. It has been recently reported that the spatial correlation patterns of resting-state BOLD signals in the white matter (WM) also give WM information often measured by diffusion tensor imaging (DTI). These correlation patterns can be captured using functional correlation tensor (FCT), which is analogous to the diffusion tensor (DT) obtained from DTI. In this paper, we propose a noise-robust FCT method aiming at further improving its quality, and making it eligible for further neuroscience study...
July 17, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28726961/functional-single-walled-carbon-nanotubes-car-for-targeting-dopamine-delivery-into-the-brain-of-parkinsonian-mice
#12
Qing Guo, Huihui You, Xu Yang, Bencheng Lin, Zhihong Zhu, Zhisong Lu, Xiaoxiao Li, Yun Zhao, Lin Mao, Shiping Shen, Haoyan Cheng, Jiting Zhang, Lingfu Deng, Jianhua Fan, Zhuge Xi, Rui Li, Chang Ming Li
Current treatments for Parkinson's disease (PD) are limited, partly due to the difficulties posed by the blood brain barrier (BBB) when delivering drugs to the brain. Herein, we explore the feasibility and efficacy of functional single-walled carbon nanotubes 'CAR' (SWCNT-PEGs-Lf) which carry and target-deliver dopamine (DA) to the brain in PD mice for treatment. SWCNTs can penetrate the cell-membrane remarkably, with the characteristics including high drug-loading and pH-dependent therapeutic unloading capacities...
July 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28725547/spatial-working-memory-in-neurofibromatosis-1-altered-neural-activity-and-functional-connectivity
#13
Amira F A Ibrahim, Caroline A Montojo, Kristen M Haut, Katherine H Karlsgodt, Laura Hansen, Eliza Congdon, Tena Rosser, Robert M Bilder, Alcino J Silva, Carrie E Bearden
BACKGROUND: Neurofibromatosis Type 1 (NF1) is a genetic disorder that disrupts central nervous system development and neuronal function. Cognitively, NF1 is characterized by difficulties with executive control and visuospatial abilities. Little is known about the neural substrates underlying these deficits. The current study utilized Blood-Oxygen-Level-Dependent (BOLD) functional MRI (fMRI) to explore the neural correlates of spatial working memory (WM) deficits in patients with NF1. METHODS: BOLD images were acquired from 23 adults with NF1 (age M = 32...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28722699/added-value-of-parotid-r2-values-for-evaluation-of-sj%C3%A3-gren-syndrome-a-preliminary-study
#14
Chen Chu, Nan Zhou, Huayong Zhang, Xin Dou, Ming Li, Song Liu, Jie Wang, Weibo Chen, Queenie Chan, Lingyun Sun, Jian He, Zhengyang Zhou
OBJECTIVE: To explore the application of parotid R2* values for evaluating Sjögren syndrome (SS). METHODS: Twenty-four consecutive SS patients and 24 sex-matched and age-matched healthy volunteers underwent bilateral parotid 3.0 T magnetic resonance (MR) imaging, including blood oxygenation level dependent sequence. Parotid R2* values of SS patients and volunteers were compared. A receiver operating characteristic analysis was used to evaluate the diagnostic performance of parotid R2* value alone and in combination with MR nodular grade...
July 2017: Journal of Computer Assisted Tomography
https://www.readbyqxmd.com/read/28717223/investigation-of-the-changes-in-the-power-distribution-in-resting-state-brain-networks-associated-with-pure-conduct-disorder
#15
Jiang Zhang, Jiansong Zhou, Fengmei Lu, Liangyin Chen, Yunzhi Huang, Huafu Chen, Yutao Xiang, Gang Yang, Zhen Yuan
Conduct disorder (CD) is a psychiatric disorder in children and adolescence. To investigate changes in the power distribution in brain networks between CD and typically developing (TD) groups, resting-state functional magnetic resonance imaging (rsfMRI) data of thirty-six subjects were first recorded, and then the data were preprocessed using DPARSF and SPM8. Meanwhile, the power of the blood oxygenation level-dependent (BOLD) signals of ninety brain regions was acquired using the integral of the Welch power spectral density (PSD)...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28709153/age-reduces-microvascular-function-in-the-leg-independent-of-physical-activity
#16
Anne Tonson, Kayle E Noble, Ronald A Meyer, Mitchell R Rozman, Kevin T Foley, Jill M Slade
The microvasculature is critical in the control of blood flow. Aging and reduced physical activity (PA) may both decrease microvascular function. PURPOSE: The primary aim was to evaluate the influence of age on microvascular function in adults with similar PA levels. Secondary aims were to assess the reliability of muscle functional magnetic resonance imaging in older adults (OA) and the relationship between PA and microvascular function in OA. METHODS: Microvascular blood-oxygen-level dependent (BOLD) responses were measured in young adults (YA, n = 12, mean ± SD age = 21 ± 1 yr old, PA = 239 ± 73 × 10 counts per day) and OA (n = 13, 64 ± 4 yr old, PA = 203 ± 48 × 10 counts per day)...
August 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28708550/unsupervised-myocardial-segmentation-for-cardiac-bold
#17
Ilkay Oksuz, Anirban Mukhopadhyay, Rohan Dharmakumar, Sotirios A Tsaftaris
A fully automated 2D+time myocardial segmentation framework is proposed for Cardiac Magnetic Resonance (CMR) Blood-Oxygen-Level-Dependent (BOLD) datasets. Ischemia detection with CINE BOLD CMR relies on spatiotemporal patterns in myocardial intensity but these patterns also trouble supervised segmentation methods, the de-facto standard for myocardial segmentation in cine MRI. Segmentation errors severely undermine the accurate extraction of these patterns. In this paper we build a joint motion and appearance method that relies on dictionary learning to find a suitable subspace...
July 12, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28708473/mr-imaging-measurements-of-altered-placental-oxygenation-in-pregnancies-complicated-by-fetal-growth-restriction
#18
Emma Ingram, David Morris, Josephine Naish, Jenny Myers, Edward Johnstone
Purpose To evaluate oxygen-enhanced and blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging parameters in normal pregnancies and those complicated by fetal growth restriction (FGR). Materials and Methods This case-control study was approved by the local research ethics committee. Informed consent was obtained from all subjects. From October 2010 to October 2015, 28 women with uncomplicated pregnancies (individualized birthweight ratio [IBR] >20th percentile and delivery >37 weeks) and 23 with pregnancies complicated by FGR (IBR <5th percentile and abnormal Doppler ultrasonography [US] studies) underwent MR imaging...
July 13, 2017: Radiology
https://www.readbyqxmd.com/read/28706728/effects-of-ageing-and-alzheimer-disease-on-haemodynamic-response-function-a-challenge-for-event-related-fmri
#19
Davud Asemani, Hassan Morsheddost, Mahsa Alizadeh Shalchy
Functional magnetic resonance imaging (fMRI) can generate brain images that show neuronal activity due to sensory, cognitive or motor tasks. Haemodynamic response function (HRF) may be considered as a biomarker to discriminate the Alzheimer disease (AD) from healthy ageing. As blood-oxygenation-level-dependent fMRI signal is much weak and noisy, particularly for the elderly subjects, a robust method is necessary for HRF estimation to efficiently differentiate the AD. After applying minimum description length wavelet as an extra denoising step, deconvolution algorithm is here employed for HRF estimation, substituting the averaging method used in the previous works...
June 2017: Healthcare Technology Letters
https://www.readbyqxmd.com/read/28705991/oxygen-metabolism-and-innate-immune-responses-in-the-gut
#20
Sean Patrick Colgan, Eric L Campbell
Epithelial cells of the mucosa provide a first line of protection against the inappropriate flux of antigens from the outside world. In the gastrointestinal (GI) tract, this barrier is provided at a number of levels, including mucus production, epithelial junctional complexes and the production of antimicrobial molecules. In recent years, it is better appreciated that tissue oxygen metabolism is key to homeostasis in the mucosa. The intestine, for example, maintains a low baseline pO2 levels due to counter-current blood flow and the presence of large numbers of bacteria...
July 13, 2017: Journal of Applied Physiology
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