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https://www.readbyqxmd.com/read/27922965/prevalence-of-different-forms-and-involved-bones-of-craniofacial-fibrous-dysplasia
#1
Liya Yang, Huanhuan Wu, Jianjian Lu, Li Teng
BACKGROUND: The purposes of this study were to analyze the prevalence of various craniofacial bones involved in patients with craniofacial fibrous dysplasia (CFD) and to demonstrate the most common form and bone involvement in patients with CFD for surgeons. METHODS: To address the research purpose, the authors designed and performed a systematic review with meta-analysis. A comprehensive electronic search without date was performed in August 2013. Data extracted from the previously published literature were analyzed with STATA 11...
December 5, 2016: Journal of Craniofacial Surgery
https://www.readbyqxmd.com/read/27908677/haemodynamic-variations-of-flow-to-renal-arteries-in-custom-made-and-pivot-branch-fenestrated-endografting
#2
J Ou, A Y S Tang, T L Chiu, K W Chow, Y C Chan, S W K Cheng
OBJECTIVE: This study aimed to investigate variation of blood flow to renal arteries in custom-made and pivot branch (p-branch) fenestrated endografting, using a computational fluid dynamics (CFD) technique. METHODS: Idealised models of custom-made and p-branch fenestrated grafting were constructed on a basis of a 26 mm stent graft. The custom-made fenestration was designed with a 6 mm diameter, while the 5 mm depth renal p-branch was created with a 6 mm inner and 15 mm outer fenestration...
November 28, 2016: European Journal of Vascular and Endovascular Surgery
https://www.readbyqxmd.com/read/27905492/high-fidelity-computational-simulation-of-thrombus-formation-in-thoratec-heartmate-ii-continuous-flow-ventricular-assist-device
#3
Wei-Tao Wu, Fang Yang, Jingchun Wu, Nadine Aubry, Mehrdad Massoudi, James F Antaki
Continuous flow ventricular assist devices (cfVADs) provide a life-saving therapy for severe heart failure. However, in recent years, the incidence of device-related thrombosis (resulting in stroke, device-exchange surgery or premature death) has been increasing dramatically, which has alarmed both the medical community and the FDA. The objective of this study was to gain improved understanding of the initiation and progression of thrombosis in one of the most commonly used cfVADs, the Thoratec HeartMate II...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27904980/a-resolved-two-way-coupled-cfd-6-dof-approach-for-predicting-embolus-transport-and-the-embolus-trapping-efficiency-of-ivc-filters
#4
Kenneth I Aycock, Robert L Campbell, Keefe B Manning, Brent A Craven
Inferior vena cava (IVC) filters are medical devices designed to provide a mechanical barrier to the passage of emboli from the deep veins of the legs to the heart and lungs. Despite decades of development and clinical use, IVC filters still fail to prevent the passage of all hazardous emboli. The objective of this study is to (1) develop a resolved two-way computational model of embolus transport, (2) provide verification and validation evidence for the model, and (3) demonstrate the ability of the model to predict the embolus-trapping efficiency of an IVC filter...
November 30, 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/27891172/vortex-analysis-of-intra-aneurismal-flow-in-cerebral-aneurysms
#5
Kevin Sunderland, Christopher Haferman, Gouthami Chintalapani, Jingfeng Jiang
This study aims to develop an alternative vortex analysis method by measuring structure ofIntracranial aneurysm (IA) flow vortexes across the cardiac cycle, to quantify temporal stability of aneurismal flow. Hemodynamics were modeled in "patient-specific" geometries, using computational fluid dynamics (CFD) simulations. Modified versions of known λ2 and Q-criterion methods identified vortex regions; then regions were segmented out using the classical marching cube algorithm. Temporal stability was measured by the degree of vortex overlap (DVO) at each step of a cardiac cycle against a cycle-averaged vortex and by the change in number of cores over the cycle...
2016: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/27890537/computational-fluid-dynamics-modeling-of-contrast-transport-in-basilar-aneurysms-following-flow-altering-surgeries
#6
Alireza Vali, Adib A Abla, Michael T Lawton, David Saloner, Vitaliy L Rayz
In vivo measurement of blood velocity fields and flow descriptors remains challenging due to image artifacts and limited resolution of current imaging methods; however, in vivo imaging data can be used to inform and validate patient-specific computational fluid dynamics (CFD) models. Image-based CFD can be particularly useful for planning surgical interventions in complicated cases such as fusiform aneurysms of the basilar artery, where it is crucial to alter pathological hemodynamics while preserving flow to the distal vasculature...
November 11, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27888933/review-on-modeling-heat-transfer-and-thermoregulatory-responses-in-human-body
#7
REVIEW
Ming Fu, Wenguo Weng, Weiwang Chen, Na Luo
Several mathematical models of human thermoregulation have been developed, contributing to a deep understanding of thermal responses in different thermal conditions and applications. In these models, the human body is represented by two interacting systems of thermoregulation: the controlling active system and the controlled passive system. This paper reviews the recent research of human thermoregulation models. The accuracy and scope of the thermal models are improved, for the consideration of individual differences, integration to clothing models, exposure to cold and hot conditions, and the changes of physiological responses for the elders...
December 2016: Journal of Thermal Biology
https://www.readbyqxmd.com/read/27885825/multiphase-fluid-solid-coupled-analysis-of-shock-bubble-stone-interaction-in-shockwave-lithotripsy
#8
K G Wang
A novel multiphase fluid-solid coupled computational framework is applied to investigate the interaction of a kidney stone immersed in liquid with a lithotripsy shock wave (LSW) and a gas bubble near the stone. The main objective is to elucidate the effects of a bubble in the shock path to the elastic and fracture behaviors of the stone. The computational framework couples a finite volume two-phase computational fluid dynamics (CFD) solver with a finite element (FE) computational solid dynamics (CSD) solver...
November 24, 2016: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/27885707/spatial-resolution-and-velocity-field-improvement-of-4d-flow-mri
#9
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/27882440/hemodynamic-changes-in-a-middle-cerebral-artery-aneurysm-at-follow-up-times-before-and-after-its-rupture-a-case-report-and-a-review-of-the-literature
#10
A Sejkorová, K D Dennis, H Švihlová, O Petr, G Lanzino, A Hejčl, D Dragomir-Daescu
Hemodynamic parameters play a significant role in the development of cerebral aneurysms. Parameters such as wall shear stress (WSS) or velocity could change in time and may contribute to aneurysm growth and rupture. However, the hemodynamic changes at the rupture location remain unclear because it is difficult to obtain data prior to rupture. We analyzed a case of a ruptured middle cerebral artery (MCA) aneurysm for which we acquired imaging data at three time points, including at rupture. A patient with an observed MCA aneurysm was admitted to the emergency department with clinical symptoms of a subarachnoid hemorrhage...
November 24, 2016: Neurosurgical Review
https://www.readbyqxmd.com/read/27882278/heat-transfer-analysis-of-underground-u-type-heat-exchanger-of-ground-source-heat-pump-system
#11
Guihong Pei, Liyin Zhang
BACKGROUND: Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. METHODS: Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature...
2016: SpringerPlus
https://www.readbyqxmd.com/read/27876371/approaches-for-treatment-of-aortic-arch-aneurysm-a-numerical-study
#12
Asaph Nardi, Idit Avrahami
Aortic arch aneurysm is a complex pathology which requires coverage of one or more aortic arch vessels. In this study we explore the hemodynamic behavior of the aortic arch in aneurysmatic and treated cases with three currently available treatment approaches: Surgery Graft, hybrid Stent-Graft and chimney Stent Graft. The analysis included four models of the time-dependent fluid domains of aneurysmatic arch and of the surgery, hybrid and chimney endovascular techniques. Dimensions of the models are based on typical anatomy, and boundary conditions are based on typical physiological flow...
November 12, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27876160/an-analysis-of-the-radioactive-contamination-due-to-radon-in-a-granite-processing-plant-and-its-decontamination-by-ventilation
#13
Pedro M Dieguez-Elizondo, Tomas Gil-Lopez, Paul G O'Donohoe, Juan Castejon-Navas, Miguel A Galvez-Huerta
This work focuses on studying concentration distribution of (222)Rn radioisotope in a granite processing plant. Using Computational Fluid Dynamic Techniques (CFD), the exposure of the workers to radiation was assessed and, in order to minimise this exposure, different decontamination scenarios using ventilation were analysed. Natural ventilation showed not sufficient to maintain radon concentration below acceptable limits, so a forced ventilation was used instead. Position of the granite blocks also revealed as a determining factor in the radioactive level distribution...
November 18, 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27875210/backward-finite-time-lyapunov-exponents-in-inertial-flows
#14
Tobias Gunther, Holger Theisel
Inertial particles are finite-sized objects that are carried by fluid flows and in contrast to massless tracer particles they are subject to inertia effects. In unsteady flows, the dynamics of tracer particles have been extensively studied by the extraction of Lagrangian coherent structures (LCS), such as hyperbolic LCS as ridges of the Finite-Time Lyapunov Exponent (FTLE). The extension of the rich LCS framework to inertial particles is currently a hot topic in the CFD literature and is actively under research...
January 2017: IEEE Transactions on Visualization and Computer Graphics
https://www.readbyqxmd.com/read/27866678/patient-specific-cfd-models-for-intraventricular-flow-analysis-from-3d-ultrasound-imaging-comparison-of-three-clinical-cases
#15
A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: As the intracardiac flow field is affected by changes in shape and motility of the heart, intraventricular flow features can provide diagnostic indications. Ventricular flow patterns differ depending on the cardiac condition and the exploration of different clinical cases can provide insights into how flow fields alter in different pathologies. METHODS: In this study, we applied a patient-specific computational fluid dynamics model of the left ventricle and mitral valve, with prescribed moving boundaries based on transesophageal ultrasound images for three cardiac pathologies, to verify the abnormal flow patterns in impaired hearts...
November 11, 2016: Journal of Biomechanics
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
#16
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/27863464/low-wall-shear-stress-is-associated-with-the-rupture-of-intracranial-aneurysm-with-known-rupture-point-case-report-and-literature-review
#17
Yisen Zhang, Linkai Jing, Ying Zhang, Jian Liu, Xinjian Yang
BACKGROUND: Few previous hemodynamic studies demonstrated the detailed features of rupture point of intracranial aneurysms. The hemodynamic simulation for the case that ruptured during angiography was even rare. In the present study, we studied the hemodynamic characteristics of a posterior communicating artery segment aneurysm that ruptured during angiography and detailed the hemodynamic features at the rupture point. CASE PRESENTATION: One 64-years-patient was 60-69 years old and suffered a subarachnoid hemorrhage within 24 h...
November 18, 2016: BMC Neurology
https://www.readbyqxmd.com/read/27863293/the-conical-stent-in-coronary-artery-improves-hemodynamics-compared-with-the-traditional-cylindrical-stent
#18
Yi Yu, Yujie Zhou, Qian Ma, Shuo Jia, Sijing Wu, Yan Sun, Xiaoli Liu, Yingxin Zhao, Yuyang Liu, Dongmei Shi
OBJECTIVES: This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). BACKGROUND: The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter...
November 8, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27861423/influence-of-iabp-induced-abdominal-occlusions-on-aortic-hemodynamics-a-patient-specific-computational-evaluation
#19
Maria Vittoria Caruso, Attilio Renzuli, Gionata Fragomeni
Intra-aortic balloon pump (IABP) is used as temporary mechanical assistance in case of cardiovascular diseases, even if different hemodynamic problems and, so, clinical complications may happen, such as the decrease of visceral perfusion. A computational fluid dynamic (CFD) study was carried out in order to investigate the effects of different IABP-induced abdominal occlusions on patient-specific aortic flow. Two possible sizes (25 cm3 and 34 cm3) and two locations (2 cm and 3 cm) of the balloon were compared, modelling four abdominal occlusions and numerically reproducing IAB inflation/deflation behaviour...
November 16, 2016: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/27855986/human-cochlear-hydrodynamics-a-high-resolution-%C3%AE-ct-based-finite-element-study
#20
Annalisa De Paolis, Hirobumi Watanabe, Jeremy T Nelson, Marom Bikson, Mark Packer, Luis Cardoso
Measurements of perilymph hydrodynamics in the human cochlea are scarce, being mostly limited to the fluid pressure at the basal or apical turn of the scalae vestibuli and tympani. Indeed, measurements of fluid pressure or volumetric flow rate have only been reported in animal models. In this study we imaged the human ear at 6.7 and 3-µm resolution using µCT scanning to produce highly accurate 3D models of the entire ear and particularly the cochlea scalae. We used a contrast agent to better distinguish soft from hard tissues, including the auditory canal, tympanic membrane, malleus, incus, stapes, ligaments, oval and round window, scalae vestibule and tympani...
November 10, 2016: Journal of Biomechanics
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