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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
#1
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
https://www.readbyqxmd.com/read/29657080/right-ventricular-energetics-and-power-in-pulmonary-regurgitation-vs-stenosis-using-four-dimensional-phase-contrast-magnetic-resonance
#2
Joao Filipe Fernandes, James M Hammel, Jia Zhou, Yunbin Xiao, Manuela Chen, Rita Alves, John Lof, Stuart M Grieve, Andreas Schuster, Titus Kuehne, Shelby Kutty
OBJECTIVE: We investigated a full energetic profile of pressure and volume loaded right ventricle (RV) in porcine models by evaluating kinetic energy (KE), stroke power, power output and power loss across pulmonary valves with stenosis (PS) or with regurgitation (PR). METHODS: Fifteen pigs (6 PS and 6 PR, 3 unoperated controls) were studied. Phase-contrast 4D-flow MRI was performed in models of PS and PR at baseline and at 10-12 weeks, in conjunction with cardiac catheterization...
April 4, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29621344/hemodynamic-forces-in-the-left-and-right-ventricles-of-the-human-heart-using-4d-flow-magnetic-resonance-imaging-phantom-validation-reproducibility-sensitivity-to-respiratory-gating-and-free-analysis-software
#3
Johannes Töger, Per M Arvidsson, Jelena Bock, Mikael Kanski, Gianni Pedrizzetti, Marcus Carlsson, Håkan Arheden, Einar Heiberg
PURPOSE: To investigate the accuracy, reproducibility and sensitivity to respiratory gating, field strength and ventricle segmentation of hemodynamic force quantification in the left and right ventricles of the heart (LV and RV) using 4D-flow magnetic resonance imaging (MRI), and to provide free hemodynamic force analysis software. MATERIALS AND METHODS: A pulsatile flow phantom was imaged using 4D flow MRI and laser-based particle image velocimetry (PIV). Cardiac 4D flow MRI was performed in healthy volunteers at 1...
2018: PloS One
https://www.readbyqxmd.com/read/29607574/wall-shear-stress-estimation-in-the-aorta-impact-of-wall-motion-spatiotemporal-resolution-and-phase-noise
#4
Judith Zimmermann, Daniel Demedts, Hanieh Mirzaee, Peter Ewert, Heiko Stern, Christian Meierhofer, Bjoern Menze, Anja Hennemuth
BACKGROUND: Wall shear stress (WSS) presents an important parameter for assessing blood flow characteristics and evaluating flow-mediated lesions in the aorta. PURPOSE: To investigate the robustness of WSS and oscillatory shear index (OSI) estimation based on 4D flow MRI against vessel wall motion, spatiotemporal resolution, and velocity encoding (VENC). STUDY TYPE: Simulated and prospective. POPULATION: Synthetic 4D flow MRI data of the aorta, simulated using the Lattice-Boltzmann method; in vivo 4D flow MRI data of the aorta from healthy volunteers (n = 11) and patients with congenital heart defects (n = 17)...
April 1, 2018: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29551938/intervention-effect-of-total-flavonoids-of-ilex-pubesceus-on-tolerant-rat-models-under-cerebral-anoxia
#5
Le Kang, Mingsan Miao
Objective: To observe the intervention effect of total flavonoid of ilex pubesceus on animal models of cerebral ischemic tolerance. Methods: A rat model of global-focal cerebral ischemic tolerance was established by blocking bilateral common carotid artery blood flow and occluding left middle cerebral artery using thread-occlusion method. After the first operation, the Ginaton group and large-dosage, medium-dosage and small-dosage groups of total flavonoid of ilex pubesceus were given intragastric administration of corresponding drugs...
December 2017: Saudi Journal of Biological Sciences
https://www.readbyqxmd.com/read/29547711/left-atrial-appendage-segmentation-and-quantitative-assisted-diagnosis-of-atrial-fibrillation-based-on-fusion-of-temporal-spatial-information
#6
Cheng Jin, Jianjiang Feng, Lei Wang, Heng Yu, Jiang Liu, Jiwen Lu, Jie Zhou
In this paper, we present an approach for left atrial appendage (LAA) multi-phase fast segmentation and quantitative assisted diagnosis of atrial fibrillation (AF) based on 4D-CT data. We take full advantage of the temporal dimension information to segment the living, flailed LAA based on a parametric max-flow method and graph-cut approach to build 3-D model of each phase. To assist the diagnosis of AF, we calculate the volumes of 3-D models, and then generate a "volume-phase" curve to calculate the important dynamic metrics: ejection fraction, filling flux, and emptying flux of the LAA's blood by volume...
March 9, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29530689/circle-of-willis-collateral-flow-in-carotid-artery-occlusion-is-depicted-by-4d-cta
#7
Midas Meijs, Frank-Erik de Leeuw, Hieronymus D Boogaarts, Rashindra Manniesing, Frederick Jan Anton Meijer
BACKGROUND: In case of carotid artery occlusion, the risk and extent of ischemic cerebral damage is highly dependent on the pathways of collateral flow, including the anatomy of the circle of Willis. In this report, cases are presented to illustrate that 4D-CTA can be considered as a non-invasive alternative to DSA for the evaluation of circle of Willis collateral flow. CASE DESCRIPTION: Five patients with unilateral internal carotid artery (ICA) occlusion underwent 4D-CTA for the evaluation of intracranial hemodynamics...
March 9, 2018: World Neurosurgery
https://www.readbyqxmd.com/read/29517139/accelerated-phase-contrast-mri-using-hybrid-one-and-two-sided-flow-encodings-only-hotfeo
#8
Da Wang, Aichi Chien, Jiaxin Shao, Fadil Abbas Ali, Peng Hu
The aim of this work was to develop and evaluate a fast phase contrast magnetic resonance imaging (PC-MRI) technique with hybrid one- and two-sided flow encodings only (HOTFEO) for accurate blood flow and velocity measurements of three-directional velocity encoding PC-MRI. Four-dimensional (4D) PC-MRI acquires flow-compensated (FC) and three-directional flow-encoded (FE) echoes in an interleaved fashion. We hypothesize that the blood flow velocity direction (not magnitude) has minimal change between two consecutive cardiac phases...
March 8, 2018: NMR in Biomedicine
https://www.readbyqxmd.com/read/29516632/volumetric-segmentation-free-method-for-rapid-visualization-of-vascular-wall-shear-stress-using-4d-flow-mri
#9
Evan M Masutani, Francisco Contijoch, Espoir Kyubwa, Joseph Cheng, Marcus T Alley, Shreyas Vasanawala, Albert Hsiao
PURPOSE: To develop a rapid segmentation-free method to visualize and compute wall shear stress (WSS) throughout the aorta using 4D Flow MRI data. WSS is the drag force-per-area the vessel endothelium exerts on luminal blood; abnormal levels of WSS are associated with cardiovascular pathologies. Previous methods for computing WSS are bottlenecked by labor-intensive manual segmentation of vessel boundaries. A rapid automated segmentation-free method for computing WSS is presented. THEORY AND METHODS: Shear stress is the dot-product of the viscous stress tensor and the inward normal vector...
March 7, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29516008/from-4d-medical-images-ct-mri-and-ultrasound-to-4d-structured-mesh-models-of-the-left-ventricular-endocardium-for-patient-specific-simulations
#10
Federico Canè, Benedict Verhegghe, Matthieu De Beule, Philippe B Bertrand, Rob J Van der Geest, Patrick Segers, Gianluca De Santis
With cardiovascular disease (CVD) remaining the primary cause of death worldwide, early detection of CVDs becomes essential. The intracardiac flow is an important component of ventricular function, motion kinetics, wash-out of ventricular chambers, and ventricular energetics. Coupling between Computational Fluid Dynamics (CFD) simulations and medical images can play a fundamental role in terms of patient-specific diagnostic tools. From a technical perspective, CFD simulations with moving boundaries could easily lead to negative volumes errors and the sudden failure of the simulation...
2018: BioMed Research International
https://www.readbyqxmd.com/read/29510510/visualization-of-concrete-slump-flow-using-the-kinect-sensor
#11
Jung-Hoon Kim, Minbeom Park
Workability is regarded as one of the important parameters of high-performance concrete and monitoring it is essential in concrete quality management at construction sites. The conventional workability test methods are basically based on length and time measured by a ruler and a stopwatch and, as such, inevitably involves human error. In this paper, we propose a 4D slump test method based on digital measurement and data processing as a novel concrete workability test. After acquiring the dynamically changing 3D surface of fresh concrete using a 3D depth sensor during the slump flow test, the stream images are processed with the proposed 4D slump processing algorithm and the results are compressed into a single 4D slump image...
March 3, 2018: Sensors
https://www.readbyqxmd.com/read/29508307/usefulness-of-four-dimensional-flow-sensitive-magnetic-resonance-imaging-to-evaluate-hemodynamics-in-the-pancreaticoduodenal-artery
#12
Yasushi Shibasaki, Takanori Sakaguchi, Ryo Kitajima, Satoru Furuhashi, Ryota Kiuchi, Makoto Takeda, Takanori Hiraide, Yoshifumi Morita, Naoki Unno, Hiroya Takeuchi
Pancreaticoduodenal artery (PDA) aneurysm associated with celiac axis compression by the median arcuate ligament (MAL) is a rare disorder, but may be lethal if ruptured. Therefore, prophylactic surgical treatments need to be considered when MAL compresses the celiac axis. We herein report the usefulness of an arterial flow analysis for objectively evaluating this pathophysiology under four-dimensional flow-sensitive magnetic resonance imaging (4D-flow MRI). Celiac artery stenosis was incidentally found under contrast-enhanced CT in a 50-year-old woman with symptomatic solitary pancreatic insulinoma...
March 5, 2018: Clinical Journal of Gastroenterology
https://www.readbyqxmd.com/read/29500919/simulation-of-personalised-haemodynamics-by-various-mounting-positions-of-a-prosthetic-valve-using-computational-fluid-dynamics
#13
Markus Bongert, Marius Geller, Werner Pennekamp, Volkmar Nicolas
Diseases of the cardiovascular system account for nearly 42% of all deaths in the European Union. In Germany, approximately 12,000 patients receive surgical replacement of the aortic valve due to heart valve disease alone each year. A three-dimensional (3D) numerical model based on patient-specific anatomy derived from four-dimensional (4D) magnetic resonance imaging (MRI) data was developed to investigate preoperatively the flow-induced impact of mounting positions of aortic prosthetic valves to select the best orientation for individual patients...
March 3, 2018: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/29499706/test-retest-variability-of-left-ventricular-4d-flow-cardiovascular-magnetic-resonance-measurements-in-healthy-subjects
#14
Victoria M Stoll, Margaret Loudon, Jonatan Eriksson, Malenka M Bissell, Petter Dyverfeldt, Tino Ebbers, Saul G Myerson, Stefan Neubauer, Carl- Johan Carlhäll, Aaron T Hess
BACKGROUND: Quantification and visualisation of left ventricular (LV) blood flow is afforded by three-dimensional, time resolved phase contrast cardiovascular magnetic resonance (CMR 4D flow). However, few data exist upon the repeatability and variability of these parameters in a healthy population. We aimed to assess the repeatability and variability over time of LV 4D CMR flow measurements. METHODS: Forty five controls underwent CMR 4D flow data acquisition...
March 2, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29493213/nanoclay-based-self-supporting-responsive-nanocomposite-hydrogels-for-printing-applications
#15
Yifei Jin, Yangyang Shen, Jun Yin, Jin Qian, Yong Huang
Stimuli-responsive hydrogels and/or composite hydrogels have been of great interest for various printing applications including four-dimensional (4D) printing. While various responsive hydrogels and/or composite hydrogels have been found to respond to given stimuli and change shapes as designed, the fabrication of three-dimensional (3D) structures from such responsive hydrogels is still a challenge due to their poor 3D printability, and most of responsive material-based patterns are two-dimensional (2D) in nature...
March 1, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29491102/evaluation-of-optimal-lymph-node-dissection-in-remnant-gastric-cancer-based-on-initial-distal-gastrectomy
#16
Kenta Iguchi, Chikara Kunisaki, Sho Sato, Yusaku Tanaka, Hiroshi Miyamoto, Takashi Kosaka, Hirotoshi Akiyama, Itaru Endo, Yasushi Rino, Munetaka Masuda
BACKGROUND/AIM: The purpose of this study was to reveal the optimal lymph node (LN) dissection in remnant gastric cancer (RGC) patients. PATIENTS AND METHODS: We retrospectively analyzed 46 RGC patients divided into two groups: patients who underwent initial gastrectomy for benign (group B) and malignant (group M) diseases. RESULTS: Metastasis was more frequently observed at the left (nos. 2, 4sa, 4sb, 10, and 11p/d) and right (nos. 1, 3, 4d, 7, 8a, and 12a) side LNs of RGC in groups M and B...
March 2018: Anticancer Research
https://www.readbyqxmd.com/read/29451963/aortic-valve-stenosis-and-aortic-diameters-determine-the-extent-of-increased-wall-shear-stress-in-bicuspid-aortic-valve-disease
#17
Emile S Farag, Pim van Ooij, R Nils Planken, Kayleigh C P Dukker, Frederiek de Heer, Berto J Bouma, Danielle Robbers-Visser, Maarten Groenink, Aart J Nederveen, Bas A J M de Mol, Jolanda Kluin, S Matthijs Boekholdt
BACKGROUND: Use of 4-dimensional flow magnetic resonance imaging (4D-flow MRI) derived wall shear stress (WSS) heat maps enables identification of regions in the ascending aorta with increased WSS. These regions are subject to dysregulation of the extracellular matrix and elastic fiber degeneration, which is associated with aortic dilatation and dissection. PURPOSE: To evaluate the effect of the presence of aortic valve stenosis and the aortic diameter on the peak WSS and surface area of increased WSS in the ascending aorta...
February 16, 2018: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29422871/age-related-vascular-changes-affect-turbulence-in-aortic-blood-flow
#18
Hojin Ha, Magnus Ziegler, Martin Welander, Niclas Bjarnegård, Carl-Johan Carlhäll, Marcus Lindenberger, Toste Länne, Tino Ebbers, Petter Dyverfeldt
Turbulent blood flow is implicated in the pathogenesis of several aortic diseases but the extent and degree of turbulent blood flow in the normal aorta is unknown. We aimed to quantify the extent and degree of turbulece in the normal aorta and to assess whether age impacts the degree of turbulence. 22 young normal males (23.7 ± 3.0 y.o.) and 20 old normal males (70.9 ± 3.5 y.o.) were examined using four dimensional flow magnetic resonance imaging (4D Flow MRI) to quantify the turbulent kinetic energy (TKE), a measure of the intensity of turbulence, in the aorta...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29422054/differential-flow-improvements-after-valve-replacements-in-bicuspid-aortic-valve-disease-a-cardiovascular-magnetic-resonance-assessment
#19
Malenka M Bissell, Margaret Loudon, Aaron T Hess, Victoria Stoll, Elizabeth Orchard, Stefan Neubauer, Saul G Myerson
BACKGROUND: Abnormal aortic flow patterns in bicuspid aortic valve disease (BAV) may be partly responsible for the associated aortic dilation. Aortic valve replacement (AVR) may normalize flow patterns and potentially slow the concomitant aortic dilation. We therefore sought to examine differences in flow patterns post AVR. METHODS: Ninety participants underwent 4D flow cardiovascular magnetic resonance: 30 BAV patients with prior AVR (11 mechanical, 10 bioprosthetic, 9 Ross procedure), 30 BAV patients with a native aortic valve and 30 healthy subjects...
February 8, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29401262/novel-insights-by-4d-flow-imaging-on-aortic-flow-physiology-after-valve-sparing-root-replacement-with-or-without-neosinuses
#20
Nicola Galea, Filippo Piatti, Francesco Sturla, Jonathan W Weinsaft, Christopher Lau, Ilaria Chirichilli, Iacopo Carbone, Emiliano Votta, Carlo Catalano, Ruggero De Paulis, Leonard N Girardi, Alberto Redaelli, Mario Gaudino
OBJECTIVES: This study was undertaken to evaluate the flow dynamics in the aortic root after valve-sparing root replacement with and without neosinuses of Valsalva reconstruction, by exploiting the capability of 4D Flow imaging to measure in vivo blood velocity fields and 3D geometric flow patterns. METHODS: Ten patients who underwent valve-sparing root replacement utilizing grafts with neosinuses or straight tube grafts (5 cases each) were evaluated by 4D Flow imaging at a mean of 46...
February 1, 2018: Interactive Cardiovascular and Thoracic Surgery
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