keyword
MENU ▼
Read by QxMD icon Read
search

4D Flow

keyword
https://www.readbyqxmd.com/read/27918636/4d-printing-of-shape-memory-based-personalized-endoluminal-medical-devices
#1
Matt Zarek, Nicola Mansour, Shir Shapira, Daniel Cohn
The convergence of additive manufacturing and shape-morphing materials is promising for the advancement of personalized medical devices. The capability to transform 3D objects from one shape to another, right off the print bed, is known as 4D printing. Shape memory thermosets can be tailored to have a range of thermomechanical properties favorable to medical devices, but processing them is a challenge because they are insoluble and do not flow at any temperature. This study presents here a strategy to capitalize on a series of medical imaging modalities to construct a printable shape memory endoluminal device, exemplified by a tracheal stent...
December 5, 2016: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/27894675/the-manifestation-of-vortical-and-secondary-flow-in-the-cerebral-venous-outflow-tract-an-in-vivo-mr-velocimetry-study
#2
Sarah Kefayati, Matthew Amans, Farshid Faraji, Megan Ballweber, Evan Kao, Sinyeob Ahn, Karl Meisel, Van Halbach, David Saloner
Aberrations in flow in the cerebral venous outflow tract (CVOT) have been implicated as the cause of several pathologic conditions including idiopathic intracranial hypertension (IIH), multiple sclerosis (MS), and pulsatile tinnitus (PT). The advent of 4D flow magnetic resonance imaging (4D-flow MRI) has recently allowed researchers to evaluate blood flow patterns in the arterial structures with great success. We utilized similar imaging techniques and found several distinct flow characteristics in the CVOT of subjects with and without lumenal irregularities...
November 15, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27891248/synchrotron-4-dimensional-imaging-of-two-phase-flow-through-porous-media
#3
F H Kim, D Penumadu, P Patel, X Xiao, E J Garboczi, S P Moylan, M A Donmez
Near real-time visualization of complex two-phase flow in a porous medium was demonstrated with dynamic 4-dimensional (4D) (3D + time) imaging at the 2-BM beam line of the Advanced Photon Source (APS) at Argonne National Laboratory. Advancing fluid fronts through tortuous flow paths and their interactions with sand grains were clearly captured, and formations of air bubbles and capillary bridges were visualized. The intense X-ray photon flux of the synchrotron facility made 4D imaging possible, capturing the dynamic evolution of both solid and fluid phases...
2016: MRS Adv
https://www.readbyqxmd.com/read/27888419/unravelling-cardiovascular-disease-using-four-dimensional-flow-cardiovascular-magnetic-resonance
#4
Vivian P Kamphuis, Jos J M Westenberg, Roel L F van der Palen, Nico A Blom, Albert de Roos, Rob van der Geest, Mohammed S M Elbaz, Arno A W Roest
Knowledge of normal and abnormal flow patterns in the human cardiovascular system increases our understanding of normal physiology and may help unravel the complex pathophysiological mechanisms leading to cardiovascular disease. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has emerged as a suitable technique that enables visualization of in vivo blood flow patterns and quantification of parameters that could potentially be of prognostic value in the disease process. In this review, current image processing tools that are used for comprehensive visualization and quantification of blood flow and energy distribution in the heart and great vessels will be discussed...
November 25, 2016: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/27885707/spatial-resolution-and-velocity-field-improvement-of-4d-flow-mri
#5
Fraser M Callaghan, Stuart M Grieve
PURPOSE: 4D-flow MRI obtains a time-dependent 3D velocity field; however, its use for the calculation of higher-order parameters is limited by noise. We present an algorithm for denoising 4D-flow data. THEORY AND METHODS: By integrating a velocity field and eliminating streamlines in noisy flow, depicted by high curvature, a denoised dataset may be extracted. This method, defined as the velocity field improvement (VFIT) algorithm, was validated in an analytical dataset and using in vivo data in comparison with a computation fluid dynamics (CFD) simulation...
November 24, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27873151/a-stereotactic-probabilistic-atlas-for-the-major-cerebral-arteries
#6
Tora Dunås, Anders Wåhlin, Khalid Ambarki, Laleh Zarrinkoob, Jan Malm, Anders Eklund
Improved whole brain angiographic and velocity-sensitive MRI is pushing the boundaries of noninvasively obtained cerebral vascular flow information. The complexity of the information contained in such datasets calls for automated algorithms and pipelines, thus reducing the need of manual analyses by trained radiologists. The objective of this work was to lay the foundation for such automated pipelining by constructing and evaluating a probabilistic atlas describing the shape and location of the major cerebral arteries...
November 21, 2016: Neuroinformatics
https://www.readbyqxmd.com/read/27863744/towards-the-improved-quantification-of-in-vivo-abnormal-wall-shear-stresses-in-bav-affected-patients-from-4d-flow-imaging-benchmarking-and-application-to-real-data
#7
F Piatti, S Pirola, M Bissell, I Nesteruk, F Sturla, A Della Corte, A Redaelli, E Votta
Bicuspid aortic valve (BAV), i.e. the fusion of two aortic valve cusps, is the most frequent congenital cardiac malformation. Its progression is often characterized by accelerated leaflet calcification and aortic wall dilation. These processes are likely enhanced by altered biomechanical stimuli, including fluid-dynamic wall shear stresses (WSS) acting on both the aortic wall and the aortic valve. Several studies have proposed the exploitation of 4D-flow magnetic resonance imaging sequences to characterize abnormal in vivo WSS in BAV-affected patients, to support prognosis and timing of intervention...
November 11, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27811406/4d-ultrafast-ultrasound-flow-imaging-in-vivo-quantification-of-arterial-volumetric-flow-rate-in-a-single-heartbeat
#8
Mafalda Correia, Jean Provost, Mickael Tanter, Mathieu Pernot
We present herein 4D ultrafast ultrasound flow imaging, a novel ultrasound-based volumetric imaging technique for the quantitative mapping of blood flow. Complete volumetric blood flow distribution imaging was achieved through 2D tilted plane-wave insonification, 2D multi-angle cross-beam beamforming, and 3D vector Doppler velocity components estimation by least-squares fitting. 4D ultrafast ultrasound flow imaging was performed in large volumetric fields of view at very high volume rate (>4000 volumes s(-1)) using a 1024-channel 4D ultrafast ultrasound scanner and a 2D matrix-array transducer...
December 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27802295/cerebral-hemodynamics-in-patients-with-hemolytic-uremic-syndrome-assessed-by-susceptibility-weighted-imaging-and-four-dimensional-non-contrast-mr-angiography
#9
Ulrike Löbel, Nils Daniel Forkert, Peter Schmitt, Torsten Dohrmann, Maria Schroeder, Tim Magnus, Stefan Kluge, Christina Weiler-Normann, Xiaoming Bi, Jens Fiehler, Jan Sedlacik
BACKGROUND AND PURPOSE: Conventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause...
2016: PloS One
https://www.readbyqxmd.com/read/27787911/accelerating-4d-flow-mri-by-exploiting-low-rank-matrix-structure-and-hadamard-sparsity
#10
Giuseppe Valvano, Nicola Martini, Adrian Huber, Claudio Santelli, Christian Binter, Dante Chiappino, Luigi Landini, Sebastian Kozerke
PURPOSE: To develop accelerated 4D flow MRI by exploiting low-rank matrix structure and Hadamard sparsity. THEORY AND METHODS: 4D flow MRI data can be represented as the sum of a low-rank and a sparse component. To optimize the sparse representation of the data, it is proposed to incorporate a Hadamard transform of the velocity-encoding segments. Retrospectively and prospectively, undersampled data of the aorta of healthy subjects are used to assess the reconstruction accuracy of the proposed method relative to k-t SPARSE-SENSE reconstruction...
October 27, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27782714/lung-surface-deformation-prediction-from-spirometry-measurement-and-chest-wall-surface-motion
#11
Joubin Nasehi Tehrani, Alistair McEwan, Jing Wang
PURPOSE: The authors have developed and evaluated a method to predict lung surface motion based on spirometry measurements, and chest and abdomen motion at selected locations. METHODS: A patient-specific 3D triangular surface mesh of the lung region was obtained at the end expiratory phase by the threshold-based segmentation method. Lung flow volume changes were recorded with a spirometer for each patient. A total of 192 selected points at a regular spacing of 2 × 2 cm matrix points were used to detect chest wall motion over a total area of 32 × 24 cm covering the chest and abdomen surfaces...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27770000/left-and-right-ventricular-hemodynamic-forces-in-healthy-volunteers-and-elite-athletes-assessed-with-4d-flow-magnetic-resonance-imaging
#12
Per Martin Arvidsson, Johannes Töger, Marcus Carlsson, Katarina Steding-Ehrenborg, Gianni Pedrizzetti, Einar Heiberg, Hakan Arheden
Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only LV forces. Right ventricular forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify three-dimensional hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. 25 controls,14 elite endurance athletes, and two patients with left ventricular dyssynchrony were included...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27740824/numerical-evidence-for-a-phase-transition-in-4d-spin-foam-quantum-gravity
#13
Benjamin Bahr, Sebastian Steinhaus
Building on recent advances in defining Wilsonian renormalization group (RG) flows, and the notion of scales in particular, for background-independent theories, we present a first investigation of the renormalization of the 4D spin-foam path integral for quantum gravity, both analytically and numerically. Focusing on a specific truncation of the model using a hypercubic lattice, we compute the RG flow and find strong indications for a phase transition, as well as an interesting interplay between the different observed phases and the (broken) diffeomorphism symmetry of the model...
September 30, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27729799/the-role-of-semaphorin-4d-in-tumor-development-and-angiogenesis-in-human-breast-cancer
#14
Hongchao Jiang, Ceshi Chen, Qiangming Sun, Jing Wu, Lijuan Qiu, Change Gao, Weiqing Liu, Jun Yang, Nie Jun, Jian Dong
BACKGROUND: Semaphorin 4D (Sema4D) is highly expressed in certain types of tumors and functions in the regulation of tumor angiogenesis and growth. However, it is still not clear regarding the roles of Sema4D in breast cancer. This study was designed to explore the effects of Sema4D on proliferation, cell cycle progression, apoptosis, invasion, migration, tumor growth, and angiogenesis in breast cancer. MATERIALS AND METHODS: The expression level of Sema4D was investigated in MCF10A, 184A1, HCC1937, MDA-MB-468, MDA-MB-231, Hs578T, BT474, MCF-7, and T47D breast cancer cell lines by Western blotting analysis...
2016: OncoTargets and Therapy
https://www.readbyqxmd.com/read/27688028/early-stage-heart-failure-with-preserved-ejection-fraction-in-the-pig-a-cardiovascular-magnetic-resonance-study
#15
Ursula Reiter, Gert Reiter, Martin Manninger, Gabriel Adelsmayr, Julia Schipke, Alessio Alogna, Alexandra Rajces, Aurelien F Stalder, Andreas Greiser, Christian Mühlfeld, Daniel Scherr, Heiner Post, Burkert Pieske, Michael Fuchsjäger
BACKGROUND: The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model. METHODS: Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress...
September 30, 2016: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/27679602/4d-flow-mri-demonstrates-changes-in-cardiovascular-haemodynamics-in-complex-congenital-heart-disease
#16
Michael Rose, Ozair Rahman, Susanne Schnell, Joshua Robinson, Cynthia Rigsby
No abstract text is available yet for this article.
September 27, 2016: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/27678106/feasibility-of-ferumoxytol-enhanced-neonatal-and-young-infant-cardiac-mri-without-general-anesthesia
#17
Lillian M Lai, Joseph Y Cheng, Marcus T Alley, Tao Zhang, Michael Lustig, Shreyas S Vasanawala
PURPOSE: To assess the feasibility of ferumoxytol-enhanced anesthesia-free cardiac MRI in neonates and young infants for complex congenital heart disease (CHD). MATERIALS AND METHODS: With Institutional Review Board approval, 21 consecutive neonates and young infants (1 day to 11 weeks old; median age of 3 days) who underwent a rapid two-sequence (MR angiography [MRA] and four-dimensional [4D] flow) MRI protocol with intravenous ferumoxytol without sedation (n = 17) or light sedation (n = 4) at 3 Tesla (T) (except one case at 1...
September 28, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27666631/dynamic-4d-ct-perfusion-offers-simultaneous-functional-and-anatomical-insights-into-pulmonary-embolism-resolution
#18
Saeed Mirsadraee, John H Reid, Martin Connell, William MacNee, Nikhil Hirani, John T Murchison, Edwin J van Beek
OBJECTIVE: Resolution and long-term functional effects of pulmonary emboli are unpredictable. This study was carried out to assess persisting vascular bed perfusion abnormalities and resolution of arterial thrombus in patients with recent pulmonary embolism (PE). METHODS AND MATERIALS: 26 Patients were prospectively evaluated by dynamic (4D) contrast enhanced CT perfusion dynamic pulmonary CT perfusion. Intermittent volume imaging was performed every 1.5-1.7s during breath-hold and perfusion values were calculated by maximum-slope technique...
October 2016: European Journal of Radiology
https://www.readbyqxmd.com/read/27666627/cloud-processed-4d-cmr-flow-imaging-for-pulmonary-flow-quantification
#19
Raluca G Chelu, Kevin W Wanambiro, Albert Hsiao, Laurens E Swart, Teun Voogd, Allard T van den Hoven, Matthijs van Kranenburg, Adriaan Coenen, Sara Boccalini, Piotr A Wielopolski, Mika W Vogel, Gabriel P Krestin, Shreyas S Vasanawala, Ricardo P J Budde, Jolien W Roos-Hesselink, Koen Nieman
OBJECTIVES: In this study, we evaluated a cloud-based platform for cardiac magnetic resonance (CMR) four-dimensional (4D) flow imaging, with fully integrated correction for eddy currents, Maxwell phase effects, and gradient field non-linearity, to quantify forward flow, regurgitation, and peak systolic velocity over the pulmonary artery. METHODS: We prospectively recruited 52 adult patients during one-year period from July 2014. The 4D flow and planar (2D) phase-contrast (PC) were acquired during same scanning session, but 4D flow was scanned after injection of a gadolinium-based contrast agent...
October 2016: European Journal of Radiology
https://www.readbyqxmd.com/read/27663769/fluid-mechanics-of-human-fetal-right-ventricles-from-image-based-computational-fluid-dynamics-using-4d-clinical-ultrasound-scans
#20
Hadi Wiputra, Chang Quan Lai, Guat Ling Lim, Joel Jia Wei Heng, Lan Guo, Sanah Merchant Soomar, Hwa Liang Leo, Arijit Biwas, Citra Nurfarah Zaini Mattar, Choon Hwai Yap
There are 0.6-1.9% of US children who were born with congenital heart malformations. Clinical and animal studies suggest that abnormal blood flow forces might play a role in causing these malformation, highlighting the importance of understanding the fetal cardiovascular fluid mechanics. We performed computational fluid dynamics simulations of the right ventricles, based on four-dimensional ultrasound scans of three 20-wk-old normal human fetuses, to characterize their flow and energy dynamics. Peak intraventricular pressure gradients were found to be 0...
December 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
keyword
keyword
25929
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"