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4D Flow

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https://www.readbyqxmd.com/read/29929053/curvelet-transform-based-volume-fusion-for-correcting-signal-loss-artifacts-in-time-of-flight-magnetic-resonance-angiography-data
#1
Ahmadreza Baghaie, Susanne Schnell, Ali Bakhshinejad, Mojtaba F Fathi, Roshan M D'Souza, Vitaliy L Rayz
Flow fields in cerebral aneurysms can be measured in vivo with phase-contrast MRI (4D Flow MRI), providing 3D anatomical magnitude images as well as 3-directional velocities through the cardiac cycle. The low spatial resolution of the 4D Flow MRI data, however, requires the images to be co-registered with higher resolution angiographic data for better segmentation of the blood vessel geometries to adequately quantify relevant flow descriptors such as wall shear stress or flow residence time. Time-of-Flight Magnetic Resonance Angiography (TOF MRA) is a non-invasive technique for visualizing blood vessels without the need to administer contrast agent...
June 15, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29925388/determination-of-aortic-stiffness-using-4d-flow-cardiovascular-magnetic-resonance-a-population-based-study
#2
Andreas Harloff, Hanieh Mirzaee, Thomas Lodemann, Paul Hagenlocher, Thomas Wehrum, Judith Stuplich, Anja Hennemuth, Jürgen Hennig, Sebastian Grundmann, Werner Vach
BACKGROUND: Increased aortic stiffness is an independent predictor of cardiovascular disease. Optimal measurement is highly beneficial for the detection of atherosclerosis and the management of patients at risk. Thus, it was our purpose to selectively measure aortic stiffness using a novel imaging method and to provide reference values from a population-based study. METHODS: One hundred twenty six inhabitants of Freiburg, Germany, between 20 and 80 years prospectively underwent 3 Tesla cardiovascular magnetic resonance (CMR) of the thoracic aorta...
June 21, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29925149/-combined-application-of-multi-parameter-semiquantitative-alberta-stroke-program-early-ct-score-to-assess-infarction-severity-in-acute-ischemic-stroke
#3
Z W Liu, Y Jiang, R Wang, J Lu, P Qi, R Y Cao, L Zhang, Z Y Shen, J Chen
Objective: To explore the significance of multi-parameter semiquantitative Alberta Stroke Program Early CT Score (ASPECTS) in detecting core infarction in acute ischemic stroke (AIS) patients. Methods: Twenty-one consecutive AIS patients from Beijing Hospital were retrospectively reviewed in this study from August 2016 to August 2017. All the patients presented within 6 hours since symptom onset.All the patients underwent one-stop dynamic whole brain 4D CTA-CTP scan before treatments (intravenous thrombolysis, mechanical thrombectomy, or other endovascular recanalization)...
June 5, 2018: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/29904131/quantitative-study-of-abdominal-blood-flow-patterns-in-patients-with-aortic-dissection-by-4-dimensional-flow-mri
#4
Dongting Liu, Zhanming Fan, Yu Li, Nan Zhang, Zhonghua Sun, Jing An, Aurélien F Stalder, Andreas Greiser, Jiayi Liu
The purpose of this study is to evaluate the hemodynamic characteristics of the true lumen (TL) and the false lumen (FL) in 16 patients with aortic dissection (AD) using 4D flow magnetic resonance imaging (MRI) and thoracic and abdominal computed tomography (CT) angiography. The quantitative parameters that were measured in the TL and FL included velocity and flow. The mean area and regurgitant fraction of the TL were significantly lesser at all four levels (p < 0.05); the average through-plane velocity, peak velocity magnitude, average net flow, peak flow, and net forward volume in the TL were considerably higher (p < 0...
June 14, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29898733/age-related-changes-of-right-atrial-morphology-and-inflow-pattern-assessed-using-4d-flow-cardiovascular-magnetic-resonance-results-of-a-population-based-study
#5
Thomas Wehrum, Thomas Lodemann, Paul Hagenlocher, Judith Stuplich, Ba Thanh Truc Ngo, Sebastian Grundmann, Anja Hennemuth, Jürgen Hennig, Andreas Harloff
BACKGROUND: To assess age-related changes of blood flow and geometry of the caval veins and right atrium (RA) using 4D flow cardiovascular magnetic resonance (CMR) data obtained in a population-based study. METHODS: An age-stratified sample (n = 126) of the population of the city of Freiburg, Germany, underwent transthoracic echocardiography and electrocardiogram-triggered and navigator-gated 4D flow CMR at 3 Tesla covering the caval veins and right heart...
June 14, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29849174/crystallisation-in-basaltic-magmas-revealed-via-in-situ-4d-synchrotron-x-ray-microtomography
#6
M Polacci, F Arzilli, G La Spina, N Le Gall, B Cai, M E Hartley, D Di Genova, N T Vo, S Nonni, R C Atwood, E W Llewellin, P D Lee, M R Burton
Magma crystallisation is a fundamental process driving eruptions and controlling the style of volcanic activity. Crystal nucleation delay, heterogeneous and homogeneous nucleation and crystal growth are all time-dependent processes, however, there is a paucity of real-time experimental data on crystal nucleation and growth kinetics, particularly at the beginning of crystallisation when conditions are far from equilibrium. Here, we reveal the first in situ 3D time-dependent observations of crystal nucleation and growth kinetics in a natural magma, reproducing the crystallisation occurring in real-time during a lava flow, by combining a bespoke high-temperature environmental cell with fast synchrotron X-ray microtomography...
May 30, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29804742/association-of-variant-arch-anatomy-with-type-b-aortic-dissection-and-hemodynamic-mechanisms
#7
Sherene Shalhub, Michal Schäfer, Thomas S Hatsukami, Matthew P Sweet, Jason J Reynolds, Ferdia A Bolster, Susanna H Shin, T Brett Reece, Niten Singh, Benjamin W Starnes, Omid Jazaeri
OBJECTIVE: Congenital aortic arch variations are more common in patients with thoracic aortic disease for reasons unknown. Additionally, little is understood about their relation to type B aortic dissections (TBAD) specifically. We investigated the prevalence of variant aortic arch anatomy in patients with TBAD compared with controls. To understand the implications of how variant aortic arch anatomy may contribute to degenerative aortic disease, we compared flow hemodynamics of three variations of aortic arches using four-dimensional flow magnetic resonance imaging (4D flow MRI)...
May 24, 2018: Journal of Vascular Surgery
https://www.readbyqxmd.com/read/29804208/scan-rescan-reproducibility-of-segmental-aortic-wall-shear-stress-as-assessed-by-phase-specific-segmentation-with-4d-flow-mri-in-healthy-volunteers
#8
Roel L F van der Palen, Arno A W Roest, Pieter J van den Boogaard, Albert de Roos, Nico A Blom, Jos J M Westenberg
OBJECTIVE: The aim was to investigate scan-rescan reproducibility and observer variability of segmental aortic 3D systolic wall shear stress (WSS) by phase-specific segmentation with 4D flow MRI in healthy volunteers. MATERIALS AND METHODS: Ten healthy volunteers (age 26.5 ± 2.6 years) underwent aortic 4D flow MRI twice. Maximum 3D systolic WSS (WSSmax) and mean 3D systolic WSS (WSSmean) for five thoracic aortic segments over five systolic cardiac phases by phase-specific segmentations were calculated...
May 26, 2018: Magma
https://www.readbyqxmd.com/read/29799061/quantification-of-aortic-stiffness-in-stroke-patients-using-4d-flow-mri-in-comparison-with-transesophageal-echocardiography
#9
Thomas Wehrum, Felix Günther, Miriam Kams, Sarah Wendel, Christoph Strecker, Hanieh Mirzaee, Andreas Harloff
To quantify stiffness of the descending aorta (DAo) in stroke patients using 4D flow MRI and compare results with transesophageal echocardiography (TEE). 48 acute stroke patients undergoing 4D flow MRI and TEE were included. Intima-media-thickness (IMT) was measured in the DAo and the aorta was scrutinized for atherosclerotic plaques using TEE. Stiffness of the DAo was determined by (a) 4D flow MRI at 3 T by calculating pulse wave velocity (PWV) and by (b) TEE calculating arterial strain, stiffness index, and distensibility coefficient...
May 24, 2018: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/29795042/electrical-resistance-tomography-for-visualization-of-moving-objects-using-a-spatiotemporal-total-variation-regularization-algorithm
#10
Bo Chen, Juan F P J Abascal, Manuchehr Soleimani
Electrical resistance tomography (ERT) has been considered as a data collection and image reconstruction method in many multi-phase flow application areas due to its advantages of high speed, low cost and being non-invasive. In order to improve the quality of the reconstructed images, the Total Variation algorithm attracts abundant attention due to its ability to solve large piecewise and discontinuous conductivity distributions. In industrial processing tomography (IPT), techniques such as ERT have been used to extract important flow measurement information...
May 24, 2018: Sensors
https://www.readbyqxmd.com/read/29757425/four-dimensional-flow-mri-analysis-of-cerebral-blood-flow-before-and-after-high-flow-extracranial-intracranial-bypass-surgery-with-internal-carotid-artery-ligation
#11
Erika Orita, Yasuo Murai, Tetsuro Sekine, Ryo Takagi, Yasuo Amano, Takahiro Ando, Kotomi Iwata, Makoto Obara, Shinichiro Kumita
BACKGROUND: The hemodynamic changes that occur after high-flow (extracranial-intracranial) EC-IC bypass surgery with internal carotid artery (ICA) ligation are not well known. OBJECTIVE: To assess blood flow changes after high-flow EC-IC bypass with ICA ligation by time-resolved 3-dimensional phase-contrast (4D Flow) magnetic resonance imaging (MRI). METHODS: We enrolled 11 patients who underwent high-flow EC-IC bypass. 4D Flow MRI was performed before and after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), bypass artery (BFVbypass), contralateral ICA (BFVcICA), and basilar artery (BFVBA)...
May 11, 2018: Neurosurgery
https://www.readbyqxmd.com/read/29737389/4d-asl-based-mr-angiography-for-visualization-of-distal-arteries-and-leptomeningeal-collateral-vessels-in-moyamoya-disease-a-comparison-of-techniques
#12
Osamu Togao, Akio Hiwatashi, Makoto Obara, Koji Yamashita, Daichi Momosaka, Ataru Nishimura, Koichi Arimura, Nobuhiro Hata, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda
OBJECTIVES: To evaluate the performance of four-dimensional pseudo-continuous arterial spin labeling (4D-pCASL)-based angiography using CENTRA-keyhole and view sharing (4D-PACK) in the visualization of flow dynamics in distal cerebral arteries and leptomeningeal anastomosis (LMA) collaterals in moyamoya disease in comparison with contrast inherent inflow-enhanced multiphase angiography (CINEMA), with reference to digital subtraction angiography (DSA). METHODS: Thirty-two cerebral hemispheres from 19 patients with moyamoya disease (mean age, 29...
May 8, 2018: European Radiology
https://www.readbyqxmd.com/read/29725666/hemodynamic-evaluation-using-four-dimensional-flow-magnetic-resonance-imaging-for-a-patient-with-multichanneled-aortic-dissection
#13
Baolei Guo, Selene Pirola, Daqiao Guo, Zhihui Dong, Xiao Yun Xu, Weiguo Fu
The hemodynamic function of multichanneled aortic dissection (MCAD) requires close monitoring and effective management to avoid potentially catastrophic sequelae. This report describes a 47-year-old man who underwent endovascular repair based on findings from four-dimensional (4D) flow magnetic resonance imaging of an MCAD. The acquired 4D flow data revealed complex, bidirectional flow patterns in the false lumens and accelerated blood flow in the compressed true lumen. The collapsed abdominal true lumen expanded unsatisfactorily after primary tear repair, which required further remodeling with bare stents...
March 2018: Journal of Vascular Surgery Cases and Innovative Techniques
https://www.readbyqxmd.com/read/29724002/synthesis-of-new-benzothiazole-acylhydrazones-as-anticancer-agents
#14
Derya Osmaniye, Serkan Levent, Abdullah Burak Karaduman, Sinem Ilgın, Yusuf Özkay, Zafer Asım Kaplancıklı
During the last five decades, a large number of BT (Benzothiazole) derivatives formed one of the eligible structures in medicinal chemistry as anticancer agents. Most of the studies reveal that various substitutions at specific positions on BT scaffold modulate the antitumor property. The potential of BTs encouraged us to synthesize a number of new 2-((5-substitutedbenzothiazol-2-yl)thio)- N &rsquo;-(2-(4-(substitutedphenyl)ethylidene)acetohydrazide derivatives and investigate their probable anticancer activity...
May 1, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29717983/whole-heart-4d-flow-cardiac-magnetic-resonance-in-healthy-dogs
#15
N Pfammatter, I Campagna, M Baron Toaldo, E Bruellmann, H Richter, P Kircher, M Dennler
In cardiac magnetic resonance imaging (CMR), accurate flow measurements rely on perpendicular plane-alignment with flow direction. For 2D phase contrast (PC) cardiac magnetic resonance measurements, planes have to be defined during the examination of the heart, which is time consuming and error-prone. Collection of flow information of the entire volume of the heart by a 4D flow CMR postpones plane alignment to post-processing. Sampling of such a large amount of data requires acceleration of data acquisition with techniques such as SENSitivity Encoding (k-t SENSE) or Broad-use Linear Acquisition Speed-up Technique (k-t BLAST)...
May 2018: Schweizer Archiv Für Tierheilkunde
https://www.readbyqxmd.com/read/29696380/geophysical-and-hydrological-data-assimilation-to-monitor-water-content-dynamics-in-the-rocky-unsaturated-zone
#16
Lorenzo De Carlo, Marco Berardi, Michele Vurro, Maria Clementina Caputo
In recent years, geophysics is increasingly used to study the flow and transport processes in the vadose zone. Particularly, when the vadose zone is made up of rocks, it is difficult to install sensors in the subsurface to measure hydrological state variables directly. In these cases, the electrical resistivity tomography (ERT) represents a useful tool to monitor the hydrodynamics of the infiltration and to estimate hydraulic parameters and state variables, such as hydraulic conductivity and water content. We propose an integrated approach aimed at predicting water content dynamics in calcarenite, a sedimentary carbonatic porous rock...
April 25, 2018: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/29695249/aortic-flow-patterns-and-wall-shear-stress-maps-by-4d-flow-cardiovascular-magnetic-resonance-in-the-assessment-of-aortic-dilatation-in-bicuspid-aortic-valve-disease
#17
José Fernando Rodríguez-Palomares, Lydia Dux-Santoy, Andrea Guala, Raquel Kale, Giuliana Maldonado, Gisela Teixidó-Turà, Laura Galian, Marina Huguet, Filipa Valente, Laura Gutiérrez, Teresa González-Alujas, Kevin M Johnson, Oliver Wieben, David García-Dorado, Arturo Evangelista
BACKGROUND: In patients with bicuspid valve (BAV), ascending aorta (AAo) dilatation may be caused by altered flow patterns and wall shear stress (WSS). These differences may explain different aortic dilatation morphotypes. Using 4D-flow cardiovascular magnetic resonance (CMR), we aimed to analyze differences in flow patterns and regional axial and circumferential WSS maps between BAV phenotypes and their correlation with ascending aorta dilatation morphotype. METHODS: One hundred and one BAV patients (aortic diameter ≤ 45 mm, no severe valvular disease) and 20 healthy subjects were studied by 4D-flow CMR...
April 26, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29675440/multi-velocity-encoding-four-dimensional-flow-magnetic-resonance-imaging-in-the-assessment-of-chronic-aortic-dissection
#18
Andrew G Sherrah, Fraser M Callaghan, Rajesh Puranik, Richmond W Jeremy, Paul G Bannon, Michael P Vallely, Stuart M Grieve
Background: Chronic descending thoracic aortic dissection (CDTAD) following surgical repair of ascending aortic dissection requires long-term imaging surveillance. We investigated four-dimensional (4D)-flow magnetic resonance imaging (MRI) with a novel multi-velocity encoding (multi-VENC) technique as an emerging clinical method enabling the dynamic quantification of blood volume and velocity throughout the cardiac cycle. Methods: Patients with CDTAD (n = 10; mean age, 55...
June 2017: Aorta (Stamford, Conn.)
https://www.readbyqxmd.com/read/29673936/comparison-between-a-generalized-newtonian-model-and-a-network-type-multiscale-model-for-hemodynamic-behavior-in-the-aortic-arch-validation-with-4d-mri-data-for-a-case-study
#19
Marine Menut, Loïc Boussel, Xavier Escriva, Benyebka Bou-Saïd, Hélène Walter-Le Berre, Yann Marchesse, Antoine Millon, Nellie Della Schiava, Patrick Lermusiaux, John Tichy
Blood is a complex fluid in which the presence of the various constituents leads to significant changes in its rheological properties. Thus, an appropriate non-Newtonian model is advisable; and we choose a Modified version of the rheological model of Phan-Thien and Tanner (MPTT). The different parameters of this model, derived from the rheology of polymers, allow characterization of the non-Newtonian nature of blood, taking into account the behavior of red blood cells in plasma. Using the MPTT model that we implemented in the open access software OpenFOAM, numerical simulations have been performed on blood flow in the thoracic aorta for a healthy patient...
May 17, 2018: Journal of Biomechanics
https://www.readbyqxmd.com/read/29666995/disturbed-left-and-right-ventricular-kinetic-energy-in-patients-with-repaired-tetralogy-of-fallot-pathophysiological-insights-using-4d-flow-mri
#20
Pia Sjöberg, Sebastian Bidhult, Jelena Bock, Einar Heiberg, Håkan Arheden, Ronny Gustafsson, Shahab Nozohoor, Marcus Carlsson
OBJECTIVES: Indications for pulmonary valve replacement (PVR) in patients with pulmonary regurgitation (PR) after repaired tetralogy of Fallot (rToF) are debated. We aimed to compare right (RV) and left ventricular (LV) kinetic energy (KE) measured by 4D-flow magnetic resonance imaging (MRI) in patients to controls, to further understand the pathophysiological effects of PR. METHODS: Fifteen patients with rToF with PR > 20% and 14 controls underwent MRI. Ventricular volumes and KE were quantified from cine MRI and 4D-flow, respectively...
April 17, 2018: European Radiology
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