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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
#1
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
#2
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
#3
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
#4
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
https://www.readbyqxmd.com/read/29385421/direct-assessment-of-tricuspid-regurgitation-by-4d-flow-cardiovascular-magnetic-resonance-in-a-patient-with-ebstein-s-anomaly
#5
Vivian P Kamphuis, Jos J M Westenberg, Pieter J van den Boogaard, Sally-Ann B Clur, Arno A W Roest
No abstract text is available yet for this article.
January 29, 2018: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/29371257/early-hemodynamic-response-assessment-of-stereotactic-radiosurgery-for-a-cerebral-arteriovenous-malformation-using-4d-flow-mri
#6
C Q Li, A Hsiao, J Hattangadi-Gluth, J Handwerker, N Farid
Brain AVMs treated with stereotactic radiosurgery typically demonstrate a minimum latency period of 1-3 years between treatment and nidus obliteration. Assessment of treatment response is usually limited to evaluation of AVM nidus structural changes using conventional MR imaging and MRA techniques. This report describes the use of 4D Flow MRI to also measure radiation-induced hemodynamic changes in a Spetzler-Martin grade III AVM, which were detectable as early as 6 months after treatment.
January 25, 2018: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/29369740/exploring-kinetic-energy-as-a-new-marker-of-cardiac-function-in-the-single-ventricle-circulation
#7
James Wong, Radomir Chabiniok, Shane M Tibby, Kuberan Pushparajah, Eva Sammut, David S Celermajer, Daniel Giese, Tarique Hussain, Gerald F Greil, Tobias Schaeffter, Reza Razavi
Ventricular volumetric ejection fraction (VV EF) is often normal in patients with single ventricle circulations despite them experiencing symptoms related to circulatory failure. We sought to determine if kinetic energy (KE) could be a better marker of ventricular performance. KE was prospectively quantified using 4D flow MRI in 41 patients with a single ventricle circulation (aged 0.5 - 28 years) and compared to 43 healthy volunteers (aged 1.5 - 62 years) and 14 patients with left ventricular (LV) dysfunction (aged 28 - 79 years)...
January 25, 2018: Journal of Applied Physiology
https://www.readbyqxmd.com/read/29369424/non-contrast-enhanced-4d-intracranial-mr-angiography-based-on-pseudo-continuous-arterial-spin-labeling-with-the-keyhole-and-view-sharing-technique
#8
Makoto Obara, Osamu Togao, Gabriele M Beck, Shuhei Shibukawa, Tomoyuki Okuaki, Masami Yoneyama, Masanobu Nakamura, Hiroshi Honda, Marc Van Cauteren
PURPOSE: 4D dynamic MR angiography (4D-MRA) using pseudo-continuous arterial spin labeling (pCASL), combined with Keyhole and View-sharing (4D-PACK) for scan acceleration, is introduced. Its validity for arterial inflow dynamics visualization was investigated through comparison with 4D-pCASL and contrast inherent inflow enhanced multiphase angiography (CINEMA). METHODS: Six healthy volunteers were included in the study. The arterial transit time (ATT) in 4D-PACK was measured at multiple regions in middle cerebral artery (MCA), and Pearson's correlation coefficient with ATT in 4D-pCASL was calculated...
January 25, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29357015/influence-of-principal-component-analysis-acceleration-factor-on-velocity-measurement-in-2d-and-4d-pc-mri
#9
Gwenaël Pagé, Jérémie Bettoni, Anne-Virginie Salsac, Olivier Balédent
OBJECTIVE: The objective of the study was to determine how to optimize 2D and 4D phase-contrast magnetic resonance imaging (PC-MRI) acquisitions to acquire flow velocities in millimetric vessels. In particular, we search for the best compromise between acquisition time and accuracy and assess the influence of the principal component analysis (PCA). MATERIALS AND METHODS: 2D and 4D PC-MRI measurements are conducted within two in vitro vessel phantoms: a Y-bifurcation phantom, the branches of which range from 2 to 5 mm in diameter, and a physiological subject-specific phantom of the carotid bifurcation...
January 22, 2018: Magma
https://www.readbyqxmd.com/read/29344990/self-gated-golden-angle-spiral-4d-flow-mri
#10
Rene Bastkowski, Kilian Weiss, David Maintz, Daniel Giese
PURPOSE: The acquisition of 4D flow magnetic resonance imaging (MRI) in cardiovascular applications has recently made large progress toward clinical feasibility. The need for simultaneous compensation of cardiac and breathing motion still poses a challenge for widespread clinical use. Especially, breathing motion, addressed by gating approaches, can lead to unpredictable and long scan times. The current work proposes a time-efficient self-gated 4D flow sequence that exploits up to 100% of the acquired data and operates at a predictable scan time...
January 17, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29332606/tricuspid-flow-and-regurgitation-in-congenital-heart-disease-and-pulmonary-hypertension-comparison-of-4d-flow-cardiovascular-magnetic-resonance-and-echocardiography
#11
Mieke M P Driessen, Marjolijn A Schings, Gertjan Tj Sieswerda, Pieter A Doevendans, Erik H Hulzebos, Marco C Post, Repke J Snijder, Jos J M Westenberg, Arie P J van Dijk, Folkert J Meijboom, Tim Leiner
BACKGROUND: Tricuspid valve (TV) regurgitation (TR) is a common complication of pulmonary hypertension and right-sided congenital heart disease, associated with increased morbidity and mortality. Estimation of TR severity by echocardiography and conventional cardiovasvular magnetic resonance (CMR) is not well validated and has high variability. 4D velocity-encoded (4D-flow) CMR was used to measure tricuspid flow in patients with complex right ventricular (RV) geometry and varying degrees of TR...
January 15, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29327165/measurement-of-cardiac-valve-and-aortic-blood-flow-velocities-in-stroke-patients-a-comparison-of-4d-flow-mri-and-echocardiography
#12
Thomas Wehrum, Felix Guenther, Alexander Fuchs, Florian Schuchardt, Anja Hennemuth, Andreas Harloff
4D flow MRI is an emerging technique that allows quantification of 3D blood flow in vivo. However, comparisons with methods of blood velocity quantification used in clinical routine are sparse. Therefore, we compared velocity quantification using 4D flow MRI with transthoracic and transesophageal echocardiography at the mitral and aortic valves and the aorta. Forty-eight stroke patients (age 67.3 ± 15.0 years) were examined by 4D flow MRI. Blood flow velocities were assessed using standardized 2D analysis planes positioned in the mitral valve (MV), aortic valve (AV), ascending aorta (AAo), and descending aorta (DAo) and were compared with echocardiography...
January 11, 2018: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/29312870/robust-principal-component-analysis-in-optical-micro-angiography
#13
Nhan Le, Shaozhen Song, Qinqin Zhang, Ruikang K Wang
Background: Recent development of optical micro-angiography (OMAG) utilizes principal component analysis (PCA), where linear-regression filter is employed to separate static and blood flow signals within optical coherence tomography (OCT). While PCA is relatively simple and computationally efficient, the technique is sensitive to and easily skewed by outliers. In this paper, robust PCA (RPCA) is thus introduced to tackle this issue in traditional PCA. Methods: We first provide brief theoretical background of PCA and RPCA in the context of OMAG where coherent (complex) OCT signals are utilized to contrast blood flow...
December 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/29305740/scan-rescan-reproducibility-of-diastolic-left-ventricular-kinetic-energy-viscous-energy-loss-and-vorticity-assessment-using-4d-flow-mri-analysis-in-healthy-subjects
#14
Vivian P Kamphuis, Jos J M Westenberg, Roel L F van der Palen, Pieter J van den Boogaard, Rob J van der Geest, Albert de Roos, Nico A Blom, Arno A W Roest, Mohammed S M Elbaz
The aim of the current study was to assess the scan-rescan reproducibility of left ventricular (LV) kinetic energy (KE), viscous energy loss (EL) and vorticity during diastole from four-dimensional flow magnetic resonance imaging (4D flow MRI) in healthy subjects. Twelve volunteers (age 27 ± 3 years) underwent whole-heart 4D flow MRI twice in one session. In-scan consistency was evaluated by correlation between KE and EL. ELindex was computed to measure the amount of EL relative to KE over diastole. Scan-rescan analysis was performed to test reproducibility of volumetric measurements of KE, EL, ELindex and vorticity in the LV over early (E) and late (A) diastolic filling...
January 5, 2018: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/29300738/hemodynamics-in-a-giant-intracranial-aneurysm-characterized-by-in-vitro-4d-flow-mri
#15
Omid Amili, Daniele Schiavazzi, Sean Moen, Bharathi Jagadeesan, Pierre-François Van de Moortele, Filippo Coletti
Experimental and computational data suggest that hemodynamics play a critical role in the development, growth, and rupture of cerebral aneurysms. The flow structure, especially in aneurysms with a large sac, is highly complex and three-dimensional. Therefore, volumetric and time-resolved measurements of the flow properties are crucial to fully characterize the hemodynamics. In this study, phase-contrast Magnetic Resonance Imaging is used to assess the fluid dynamics inside a 3D-printed replica of a giant intracranial aneurysm, whose hemodynamics was previously simulated by multiple research groups...
2018: PloS One
https://www.readbyqxmd.com/read/29288123/correlations-between-sonographic-and-urodynamic-findings-after-mid-urethral-sling-surgery
#16
Lieming Wen, Ka Lai Shek, Subramaniam Nishamini, Friedman Talia, Hans Peter Dietz
PURPOSE: To study correlations between sonographic and urodynamic findings after suburethral sling surgery. METHODS: This is a retrospective study on 141 women who had multichannel urodynamic testing and translabial 4D ultrasound after suburethral sling surgery between 2006 and 2016. The sling-pubis gap, i.e., the distance between sling and infero-posterior margin of the pubic symphysis on Valsalva, and urethral motion profile were determined. The urethral motion profile was assessed by calculating the mobility vectors of 6 equidistant points along the length of urethra from bladder neck to external urethral meatus, against the dorsocaudal margin of the symphysis pubis on Valsalva...
December 26, 2017: Journal of Urology
https://www.readbyqxmd.com/read/29287138/4d-fetal-echocardiography-an-update
#17
Greggory R DeVore, Gary Satou, Mark Sklansky
With the introduction of the electronic 4-dimensional and spatial-temporal image Correlation (e-STIC), it is now possible to obtain large volume datasets of the fetal heart that are virtually free of artifact. This allows the examiner to use a number of imaging modalities when recording the volumes that include two-dimensional real time, power and color Doppler, and B-flow images. Once the volumes are obtained, manipulation of the volume dataset allows the examiner to recreate views of the fetal heart that enable examination of cardiac anatomy...
December 2017: Echocardiography
https://www.readbyqxmd.com/read/29279196/experimental-quantification-of-the-fluid-dynamics-in-blood-processing-devices-through-4d-flow-imaging-a-pilot-study-on-a-real-oxygenator-heat-exchanger-module
#18
Filippo Piatti, Maria Chiara Palumbo, Filippo Consolo, Francesca Pluchinotta, Andreas Greiser, Francesco Sturla, Emiliano Votta, Sergii V Siryk, Riccardo Vismara, Gianfranco Beniamino Fiore, Massimo Lombardi, Alberto Redaelli
The performance of blood-processing devices largely depends on the associated fluid dynamics, which hence represents a key aspect in their design and optimization. To this aim, two approaches are currently adopted: computational fluid-dynamics, which yields highly resolved three-dimensional data but relies on simplifying assumptions, and in vitro experiments, which typically involve the direct video-acquisition of the flow field and provide 2D data only. We propose a novel method that exploits space- and time-resolved magnetic resonance imaging (4D-flow) to quantify the complex 3D flow field in blood-processing devices and to overcome these limitations...
December 15, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29260346/assessment-of-mitral-regurgitation-by-3-dimensional-proximal-flow-convergence-using-magnetic-resonance-imaging-comparison-with-echo-doppler
#19
Lior Gorodisky, Yoram Agmon, Moshe Porat, Sobhi Abadi, Jonathan Lessick
To test the feasibility of assessing mitral regurgitation (MR) severity using cardiac magnetic resonance (CMR) 4D velocity vectors to quantify regurgitant volume (RVol) by analysis of the proximal flow convergence, compared to Doppler based proximal isovelocity surface area (PISA) and CMR volume-based methods. In a prospectively designed study, 27 patients with various grades of MR underwent CMR and echo-Doppler on the same day. By CMR, multiple slices were obtained parallel to the mitral valve by phase-contrast imaging, using 3D velocity vectors, as well as short-axis cine images for left and right ventricular volume measurements...
December 19, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/29248286/perioperative-evaluation-of-regional-aortic-wall-shear-stress-patterns-in-patients-undergoing-aortic-valve-and-or-proximal-thoracic-aortic-replacement
#20
Emilie Bollache, Paul W M Fedak, Pim van Ooij, Ozair Rahman, S Chris Malaisrie, Patrick M McCarthy, James C Carr, Alex Powell, Jeremy D Collins, Michael Markl, Alex J Barker
OBJECTIVES: To assess in patients with aortopathy perioperative changes in thoracic aortic wall shear stress (WSS), which is known to affect arterial remodeling, and the effects of specific surgical interventions. METHODS: Presurgical and postsurgical aortic 4D flow MRI were performed in 33 patients with aortopathy (54 ± 14 years; 5 women; sinus of Valsalva (d_SOV)/midascending aortic (d_MAA) diameters = 44 ± 5/45 ± 6 mm) scheduled for aortic valve (AVR) and/or root (ARR) replacement...
November 16, 2017: Journal of Thoracic and Cardiovascular Surgery
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