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Pc asl

Per Eckerbom, Peter Hansell, Eleanor F Cox, Charlotte Buchanan, Jan Weis, Fredrik Palm, Susan T Francis, Per Liss
Non-invasive methods of magnetic resonance imaging (MRI) can quantify parameters of kidney function. The main purpose of this study was to determine baseline values of such parameters in healthy volunteers. In 28 healthy volunteers (15 females, 13 males), Arterial Spin Labeling (ASL) to estimate regional renal perfusion, Blood Oxygen Level Dependent (BOLD) transverse relaxation rate (R2 *) to estimate oxygenation, and Apparent Diffusion Coefficient (ADC), true diffusion (D) and longitudinal relaxation time (T1 ) to estimate tissue properties were determined bilaterally in the cortex, outer and inner medulla...
January 16, 2019: American Journal of Physiology. Renal Physiology
Chris Baeken, Josefien Dedoncker, Jonathan Remue, Guo-Rong Wu, Marie-Anne Vanderhasselt, Sara De Witte, Tasha Poppa, Jill M Hooley, Rudi De Raedt
Transcranial direct current stimulation (tDCS) is a potential treatment strategy for mood and anxiety disorders, but how this application may influence emotional processes, and whether this is related to individual characteristics, is not well understood. It has been proposed that perceived criticism (PC) may represent a vulnerability factor for the development of such mental illnesses. To decipher whether neural mechanisms of action of tDCS potentially differ depending on PC status (low vs. high), we evaluated mood and brain perfusion before and after applying MRI-compatible tDCS, and after participants were exposed to verbal criticism in the scanner...
November 2018: Human Brain Mapping
Zhiye Chen, Xiaoyan Chen, Mengyu Liu, Mengqi Liu, Lin Ma, Shengyuan Yu
BACKGROUND: Although previous studies have demonstrated that structural and functional abnormalities in episodic migraine (EM), less is known about altered brain perfusion in the EM. The aim of this study is to investigate altered gray matter perfusion in EM using a 3D volumetric perfusion imaging. METHODS: Fifteen EM patients and 15 normal controls (NC) underwent structural and 3D pseudo-continuous arterial spin labeling (3D pc-ASL). The structural images were segmented using DARTEL methods and the generated normalized T1 tissue probability maps were used to coregister the cerebral blood flow (CBF) images, which would further be performed with standardization using Fisher Z Transformation...
May 23, 2018: Journal of Headache and Pain
Meng-Qi Liu, Zhi-Ye Chen, Lin Ma
Objective To evaluate the reliability of three dimensional spiral fast spin echo pseudo-continuous arterial spin labeling (3D pc-ASL) in measuring cerebral blood flow (CBF) with different post-labeling delay time (PLD) in the resting state and the right finger taping state. Methods 3D pc-ASL and three dimensional T1-weighted fast spoiled gradient recalled echo (3D T1-FSPGR) sequence were applied to eight healthy subjects twice at the same time each day for one week interval. ASL data acquisition was performed with post-labeling delay time (PLD) 1...
March 30, 2018: Chinese Medical Sciences Journal, Chung-kuo i Hsüeh K'o Hsüeh Tsa Chih
Peiying Liu, Ying Qi, Zixuan Lin, Qiyong Guo, Xiaoming Wang, Hanzhang Lu
Abnormal cerebral blood flow (CBF) is implicated in several neonatal and infant diseases. However, measurement of CBF in this population remains difficult and has not been used in routine clinical MRI. Arterial spin labeling (ASL) methods suffer from both low SNR and poor quantification when applied to very young children. Furthermore, rapid change in brain physiology in this age range makes it difficult to choose sequence parameters such as labeling pulse flip angle and post labeling delay. Phase-contrast (PC) MRI is another approach to measure flow...
March 10, 2018: NeuroImage
Adam Bush, Yaqiong Chai, So Young Choi, Lena Vaclavu, Scott Holland, Aart Nederveen, Thomas Coates, John Wood
PURPOSE: To investigate possible sources of quantification errors in global cerebral blood flow (CBF) measurements by comparing pseudo continuous arterial spin labeling (PCASL) and phase contrast (PC) MRI in anemic, hyperemic subjects. METHODS: All studies were performed on a Philips 3T Achieva MRI scanner. PC and PCASL CBF examinations were performed in 10 healthy, young adult subjects and 18 young adults with chronic anemia syndromes including sickle cell disease and thalassemia...
April 2018: Magnetic Resonance Imaging
Meng-Qi Liu, Zhi-Ye Chen, Lin Ma
OBJECTIVE: To evaluate the test-retest reliability of 3D spiral fast-spin-echo (FSE) pseudo-continuous arterial spin labeling (3D pc-ASL) for cerebral perfusion imaging of the subcortical gray matter in healthy adults in resting state. METHODS: 3D spiral FSE ASL and 3D T1-weighted fast spoiled gradient recalled echo (3D T1-FSPGR) sequences were used for cerebral perfusion imaging in 8 healthy adult subjects, and a repeat imaging examination was performed after one week...
September 20, 2017: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Minhui Ouyang, Peiying Liu, Tina Jeon, Lina Chalak, Roy Heyne, Nancy K Rollins, Daniel J Licht, John A Detre, Timothy P L Roberts, Hanzhang Lu, Hao Huang
The human brain develops rapidly during 32-45 postmenstrual weeks (PMW), a critical stage characterized by dramatic increases of metabolic demand. The increasing metabolic demand can be inferred through measurements of regional cerebral blood flow (CBF), which might be coupled to regional metabolism in preterm brains. Arterial spin labeled (ASL) perfusion MRI is one of the few viable approaches for imaging regional CBF of preterm brains, but must be optimized for the extremely slow blood velocity unique in preterm brains...
February 15, 2017: NeuroImage
Taiga Itagaki, Desmond J Bennett, Christopher T Chenelle, Daniel F Fisher, Robert M Kacmarek
BACKGROUND: Volume-targeted ventilation is increasingly used in low birthweight infants because of the potential for reducing volutrauma and avoiding hypocapnea. However, it is not known what level of air leak is acceptable during neonatal volume-targeted ventilation when leak compensation is activated concurrently. METHODS: Four ICU ventilators (Servo-i, PB980, V500, and Avea) were compared in available invasive volume-targeted ventilation modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV])...
January 2017: Respiratory Care
Taiga Itagaki, Christopher T Chenelle, Desmond J Bennett, Daniel F Fisher, Robert M Kacmarek
BACKGROUND: During both nasal noninvasive ventilation (NIV) and invasive ventilation of neonates, the presence of air leaks causes triggering and cycling asynchrony. METHODS: Five ICU ventilators (PB840, PB980, Servo-i, V500, and Avea) were compared in available invasive ventilation and NIV ventilator modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The V500 and Avea do not provide PC-CSV and PC-CMV in NIV...
January 2017: Respiratory Care
Siobhan M Hoscheidt, J Mikhail Kellawan, Sara E Berman, Leonardo A Rivera-Rivera, Rachel A Krause, Jennifer M Oh, Michal S Beeri, Howard A Rowley, Oliver Wieben, Cynthia M Carlsson, Sanjay Asthana, Sterling C Johnson, William G Schrage, Barbara B Bendlin
Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals...
June 2017: Journal of Cerebral Blood Flow and Metabolism
Robert L Chatburn, Eduardo Mireles-Cabodevila, Madhu Sasidhar
UNLABELLED: Tidal volume (VT) measurement during pressure control (PC) ventilation with preset inspiratory time may produce errors due to patient inspiratory effort. We evaluated VT error in 3 common ICU ventilators. METHODS: Simulated patient: 60kg adult with ARDS using IngMar Medical ASL 5000 having moderate inspiratory effort. Ventilators evaluated: Covidien PB 840, Maquet Servo-i, and Dräger Evita XL, PC breaths at preset inspiratory time (TI) 0.6-1.4s. VT error was defined as ventilator displayed VT minus the simulator displayed VT (mL/kg or % of true)...
August 1, 2016: Computers in Biology and Medicine
P Vilela, M Pimentel, I Sousa, P Figueiredo
Arterial spin labeling (ASL) is a non-invasive MRI technique that allows the quantitative measurement of perfusion, (regional cerebral blood flow (rCBF)). The ASL techniques use the labeling of the blood, by inverting or saturating the spins of water molecules of the blood supplying the imaged region. When reaching the capillary bed, these will be exchanged with tissue water giving rise to a perfusion-weighted signal. The subtraction of control (without label) from labeled images yields a signal difference that directly reflects the local perfusion...
March 29, 2011: Neuroradiology Journal
Andrew J Wheaton, Mitsue Miyazaki
Noncontrast-enhanced magnetic resonance angiography (NCE-MRA) methods have been demonstrated in anatomies throughout the body. Previously established NCE-MRA techniques suffered from long scan times or low sensitivity. Advances in hardware and software have made NCE-MRA scan times clinically feasible. Recent concerns over the safety of gadolinium-based contrast material combined with the expense of the material and its administration have generated a demand for NCE-MRA. In response, several new NCE-MRA methods have been developed...
August 2012: Journal of Magnetic Resonance Imaging: JMRI
Laxman Mainali, Marija Raguz, Theodore G Camenisch, James S Hyde, Witold K Subczynski
Saturation-recovery (SR) EPR at W-band (94 GHz) to obtain profiles of the membrane fluidity and profiles of the oxygen transport parameter is demonstrated for lens lipid membranes using phosphatidylcholine (n-PC), stearic acid (n-SASL), and cholesterol analog (ASL and CSL) spin labels, and compared with results obtained in parallel experiments at X-band (9.4 GHz). Membranes were derived from the total lipids extracted from 2-year-old porcine lens cortex and nucleus. Two findings are especially significant. First, measurements of the spin-lattice relaxation times T1 for n-PCs allowed T1 profiles across the membrane to be obtained...
September 2011: Journal of Magnetic Resonance
R S Lanzman, P Schmitt, P Kröpil, D Blondin
Especially in regard to the potential risks for the development of nephrogenic systemic fibrosis (NSF) following the administration of Gadolinium-based contrast material, nonenhanced MR angiography (MRA) methods are becoming ever more important. Besides well-established time-of-flight (TOF) and phase-contrast (PC) MRA, alternative imaging techniques based on balanced steady-state free precession (bSSFP) and turbo-spin-echo (TSE) sequences are increasingly used in combination with or without arterial spin labeling (ASL) strategies...
October 2011: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
Marija Raguz, Laxman Mainali, Justyna Widomska, Witold K Subczynski
Electron paramagnetic resonance (EPR) spin-labeling methods were used to study the organization of cholesterol and phospholipids in membranes formed from Chol/POPS (cholesterol/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine) mixtures, with mixing ratios from 0 to 3. It was confirmed using the discrimination by oxygen transport and polar relaxation agent accessibility methods that the immiscible cholesterol bilayer domain (CBD) was present in all of the suspensions when the mixing ratio exceeded the cholesterol solubility threshold (CST) in the POPS membrane...
April 2011: Biochimica et Biophysica Acta
Hanna Järnum, Elena G Steffensen, Linda Knutsson, Ernst-Torben Fründ, Carsten Wiberg Simonsen, Søren Lundbye-Christensen, Ajit Shankaranarayanan, David C Alsop, Finn Taagehøj Jensen, Elna-Marie Larsson
INTRODUCTION: The purpose of this study was to compare the non-invasive 3D pseudo-continuous arterial spin labelling (PC ASL) technique with the clinically established dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-MRI) for evaluation of brain tumours. METHODS: A prospective study of 28 patients with contrast-enhancing brain tumours was performed at 3 T using DSC-MRI and PC ASL with whole-brain coverage. The visual qualitative evaluation of signal enhancement in tumour was scored from 0 to 3 (0 = no signal enhancement compared with white matter, 3 = pronounced signal enhancement with equal or higher signal intensity than in grey matter/basal ganglia)...
April 2010: Neuroradiology
Golnaz Bahramali, Majid Sadeghizadeh, Samad Amini-Bavil-Olyaee, Seyed-Moayed Alavian, Abbas Behzad-Behbahani, Ahmad Adeli, Mohammad-Reza Aghasadeghi, Safieh Amini, Fereidoun Mahboudi
AIM: To characterize the clinical, serologic and virologic features of hepatitis B virus (HBV) infection in Iranian patients with different stages of liver disease. METHODS: Sixty two patients comprising of 12 inactive carriers, 30 chronic hepatitis patients, 13 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma (HCC) were enrolled in the study. The HBV S, C and basal core promoter (BCP) regions were amplified and sequenced, and the clinical, serologic, phylogenetic and virologic characteristics were investigated...
September 21, 2008: World Journal of Gastroenterology: WJG
K K W Siu, K S Morgan, D M Paganin, R Boucher, K Uesugi, N Yagi, D W Parsons
We seek to establish non-invasive imaging able to detect and measure aspects of the biology and physiology of surface fluids present on airways, in order to develop novel outcome measures able to validate the success of proposed genetic or pharmaceutical therapies for cystic fibrosis (CF) airway disease. Reduction of the thin airway surface liquid (ASL) is thought to be a central pathophysiological process in CF, causing reduced mucociliary clearance that supports ongoing infection and destruction of lung and airways...
December 2008: European Journal of Radiology
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