## Articles Related to Flow Visualization

Maryam Alizadeh, Melissa Cote, Alexandra Branzan Albu -J. of Medical Imaging, 8(1) (12 February 2021)

Prosthetic heart valve designs must be rigorously tested using cardiovascular equipment... ...Using video frames recorded with a high-speed digital camera during in vitro simulations, an initial estimation of the orifice area is first obtained via active contouring and thresholding and then refined to capture the leaflet free edges via a curve transformation mechanism. Results: Experiments on video data from pulsatile flow testing demonstrate the effectiveness of our approach...

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Paulo Yu, Vibhav Durgesh, Tao Xing, Ralph Budwig -J Biomech Eng. Published Online: February 4, 2021

Aneurysms are localized expansions of weakened blood vessels that can be debilitating or fatal upon rupture... ...the objective of this study was to demonstrate the application of Proper Orthogonal Decomposition (POD) to study the impact of different inflow conditions on energetic flow structures and their temporal behavior in an aneurysm. To achieve this objective, experiments were performed on an idealized rigid sidewall aneurysm model. A piston pump system was used for precise inflow control, i.e., peak Reynolds number ($Re_p$) and Womersley number ($\alpha$) were varied from 50-270 and 2-5, respectively.... … These settings provided approximately 9000 vectors in the pipe region, 6000 vectors in the neck region, and 6800 vectors in the sac region. 3.3 Pump system To generate controlled inflow conditions for this study, a piston pump (ViVitro Labs Inc …

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Sanjiv Gunasekera, Olivia Ng, Shannon Thomas, Ramon Varcoe, Charitha de Silva & Tracie Barber - Experiments in Fluids, 2020

The arteriovenous fistula (AVF), which is a vasculature created for end-stage renal disease patients who require haemodialysis, is susceptible to many vascular diseases. ...The current study is an investigation of the complex three-dimensional flow within a physiological AVF geometry, using tomographic particle image velocimetry... … The ViVitro Superpump (ViVitro Labs Inc., BC, Canada) was used as the flow source and a network of rigid Tygon tubing inclusive of valves, to simulate vascular resistance, and air-filled syringes, to simulate vascular compliance, connected the model to the pump …

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Jana Fuchsberger Philipp Aigner Gundolf Haase Steven Niederer Heinrich Schima Gernot Plank Elias Karabela - September 2020 preprint rxiv.org

Simulating the interaction of fluids with immersed moving solids is playing an important role for gaining a better quantitative understanding of how fluid dynamics is altered by the presence of obstacles and, vice versa, which forces are exerted on the solids by the moving fluid... ...application problems with focus on understanding the effect of solids on altering fluid dynamics. In this study we report on the development of a novel method for such applications. In our method rigid moving obstacles are incorporated in a fluid dynamics context using concepts from porous media theory. Based on the Navier-Stokes-Brinkman equations... ...and a piston pump (SuperPump, ViVitro Labs Inc., Victoria, BC, Canada) were used to generate stationary and pulsating inflows....

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Jason Voorneveld, Hicham Saaid, Christiaan Schinkel, Nikola Radeljic, Boris Lippe, Frank J.H. Gijsen, Antonius F.W.van der Steen, Nico de Jong, Tom Claessens, Hendrik J. Vos, Sasa Kenjeres, Johan G. Bosch - Elsevier Ultrasound in Medicine & Biology - Available online 8 January 2020

Left ventricular (LV) blood flow is an inherently complex time-varying 3-D phenomenon, where 2-D quantification often ignores the effect of out-of-plane motion. In this study, we describe high frame rate 4-D echocardiographic particle image velocimetry (echo-PIV) using a prototype matrix transesophageal transducer and a dynamic LV phantom for testing the accuracy of echo-PIV in the presence of complex flow patterns.... … 1a). The mitral and aortic tracts of the LV were connected to atrial and compliance chambers (transparent acrylic, built in-house), which were connected via a tube with an adjustable resistance valve (ViVitro Labs … ... We demonstrate that 4-D echo-PIV could be performed in just four heart cycles, which would require only a short breath-hold, providing promising results. However, methods for resolving high velocity gradients in regions of poor spatial resolution are required before clinical translation....

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HH Yeh - 2019 UBC Theses and Dissertations

... thesis firstly evaluated the biomechanical contributions to ATAA progression under the influence of anatomy, hypertension, and hematocrit using fully coupled fluid-structure interaction (FSI) with arterial wall anisotropy to provide additional information in patient evaluations... ...The three different ATAA models identified different aortic expansions that were not uniform under pulsatile pressure and a geometry depended on elevated wall stress under hypertension.... ... A commercially available, 23 mm BMHV with a tissue annulus diameter / internal diameter (TAD/ID) of 18.5 mm (Figure 3.2), was used as the test model. ViVitro pulse duplicator was used to assess the performance and function of prosthetic heart valves under simulated cardiac conditions. ...

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Yen Ngoc Nguyen, Edgar Lik Wui Tay, Foad Kabinejadian, Chi Wei Ong, Munirah Ismail, and Hwa Liang Leo -American Journal of Physiology-Heart and Circulatory Physiology 11 OCT 2019

The deteriorating nature of severe functional tricuspid regurgitation (FTR) has led to the heightened interest in this pathology... ...In this study, the hemodynamics of the right ventricle (RV) after (i) clover edge-to-edge tricuspid repair and (ii) double orifice tricuspid repair was evaluated in three right heart models using an ex vivo pulsatile platform emulating severe FTR with the aid of stereoscopic particle image velocimetry... … circulation (35). A closed ventricular chamber housing the silicon RV model was directly 184 connected to the pulsatile wave-generating piston pump (SuperPump AR series, ViVitro Labs 185 Inc., Victoria, BC, Canada) to …

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Han HungYeh, Oleksandr Barannyk, Dana Grecov, Peter Oshkaid - Computers in Biology and Medicine Volume 110, July 2019, Pages 79-92

...the objective of this study is to analyze the hemodynamics and valve mechanics of a bileaflet mechanical heart valve and investigate the hemorheological characteristics under the change of hematocrit.... … Fig. 2. Schematic illustrating DPIV test set-up used in the current experiment (Image courtesy of ViVitro Labs Inc.). To simulate the physiological flow conditions, an acrylic test chamber, that represented a simplified model of … ...The current numerical analysis revealed the hematocrit influenced the shear stress distributions over a cardiac cycle...

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P Yu Electronic Theses & Dissertations (ETDs) (2011-) [3339] 2018

...This study focuses on investigating the hemodynamics inside an aneurysm for different inflow conditions and varying geometrical shapes. ... … precisely controlled. Re and α were varied between 50-250 and 2-5, respectively. A ViVitro Labs pump system was used to pump the fluid and Particle Image Velocimetry (PIV) was used to perform velocity measurements. The flow …

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H Saaid, P Segers, M Novara, T Claessens, P Verdonck - Experiments in Fluids, 2018

...The effects of the orientation of a prosthetic mitral valve in anatomical and anti-anatomical configurations have been investigated during the diastolic filling time... … A commercially available cardiovascular simulator (Vivitro Systems, Inc., Victoria, BC, Canada) that can impose and monitor different physiological pressure and flow conditions was adopted. The hydraulic piston pump was connected to the inner tank …

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S Houser, I Okafor, V Raghav, A Yoganathan - Journal of Visualization First Online: 16 February 2018

...The objective of this study was to characterize three distinct orientations (30°, 60° and 90°) of the non-parallel jet–vortex interaction in a simplified flow loop... … 1 Experimental setup of jet–vortex interaction flow loop. A programmable pulsatile pump (ViVitro SuperPump) allowed for controlled, isolated vortex rings to be ejected into the chamber, as shown in Fig. 2. The flow profile for vortex ring ejection is shown in Fig …

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Munirah Ismail, Foad Kabinejadian, Yen Ngoc Nguyen, Edgar Tay Lik Wui, Sangho Kim, Hwa Liang Leo - - Medical Engineering and Physics October 25, 2017

...The study utilises both 2-D and 3-D particle image velocimetry (PIV) to interrogate the flow patterns in the vicinity of the extra-cardiac tricuspid valves in an in vitro physiological flow loop, specifically at four measurement locations in the cavo-atrial anatomy. ... ... of the hepatic vein. In contrast, the SVC valve was fully implanted in the SVC. The mock circulatory system was driven by a pulse generator (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada). It comprised of an ultrasonic ...

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W Conlin, P Yu, V Durgesh - Bulletin of the American Physical Society, 2017

...The objective of this study is to identify the large-scale structures in the aneurysm, study temporal behavior, and quantify their interaction with the inflow condition. ... ... For this purpose, detailed Particle Image Velocimetry (PIV) measurements were performed at the center plane of an idealized aneurysm model for a range of inflow conditions. Inflow conditions were precisely controlled using a ViVitro SuperPump system. ...

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P Yu, V Durgesh, H Johari - Bulletin of the American Physical Society, 2017

...Studies have shown that hemodynamics is integral to developing an understanding of aneurysm formation, growth, and rupture. This investigation focuses on a comprehensive study of the impact of varying inflow conditions and aneurysm shapes on spatial and temporal behavior of flow parameters and structures in an aneurysm.... ... For this purpose, detailed Particle Image Velocimetry (PIV) measurements were performed at the center plane of an idealized aneurysm model for a range of inflow conditions. Inflow conditions were precisely controlled using a ViVitro SuperPump system. ...

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M. Alizadeh, M. Cote, and A Branzan Albu P Sharma, FM Bianchi - Image Analysis 20th Scandinavian Conference, SCIA 2017,

...The valve orifi ce area over time, which informs on the opening and closing motion patterns, constitutes a key quality metric for PHV assessment... ...In this paper, we propose a novel orifi ce segmentation approach for automatic prosthetic heart valves quantitative performance analysis, based on the detection of the leaflet free edges to accurately extract the actual orifi ce area.

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Riccardo Toninatoa, Jacob Salmona, Francesca Maria Susin, Andrea Duccia, Gaetano Burriescia doi:10.1016/j.jbiomech.2016.05.027

The physiological flow dynamics within the Valsalva sinuses, in terms of global and local parameters, are still not fully understood. This study attempts to identify the physiological conditions as closely as possible, and to give an explanation of the different and sometime contradictory results in literature. ... 2. Material and Methods. In this study, all experiments were carried out using a hydro-mechanical pulse duplicator (Vivitro Superpump System SP3891, ViVitro Labs Inc., Canada), with pressure catheters monitoring the pressure upstream and downstream of the aortic valve. ...

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Jahren, Silje Ekroll; Heinisch, Paul Philipp; Wirz, Jessica; Winkler, Bernhard; Carrel, Thierry; Obrist, Dominik (31 March 2015). Hemodynamic Performance of Edwards Intuity Valve in a Compliant Aortic Root Model (In Press). In: IEEE EMBC 2015. Milano. 25.08.-29.08.2015.

...It was the aim of this study to perform hemodynamic and kinematic measurements for this type of valves to serve as a baseline for following studies which investigate the effect of the aortic root on the valve performance. To this end, the Edwards Intuity aortic valve was investigated in a new in vitro flow loop mimicking the left heart...

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Bernhard Vennemann, David Hasler, Silje E. Jahren, Thomas Rösgen, Thierry P. Carrel, Dominik Obrist - Heart Valve Society 1st Annual Meeting MAY 6-9, MONTE CARLO, MONACO, GRIMALDI FORUM

...so called hot spots, where activated platelets might aggregate and form a thrombus that can ultimately lead to leaflet blockage. It is the aim of this study to assess the hemodynamics in the pivoting area of the Triflo valve.

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Ikechukwu U. Okafor, Arvind Santhanakrishnan, Brandon D. Chaffins, Lucia Mirabella, John N. Oshinski and Ajit P. Yoganathan - Journal of Cardiovascular Magnetic Resonance 2015, 17:51 doi:10.1186/s12968-015-0154-9

... A programmable piston pump (PPP; Vivitro Systems Inc., Victoria, Canada) was used to induce the LV wall motion by altering the pressure of the fluid in the space between the interior of acrylic chamber housing the LV model and the exterior of the LV model. ...

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Clara Seaman, Andrew McNally, Stephen Biddle, Lauren Jankowski, Philippe Sucosky Presented in part at the 2013 Biomedical Engineering Society Conference, September 2013, Seattle, WA, and at the 2013 ASME Summer Bioengineering Conference, June 2013, Sunriver, OR, USA

The study aim was to develop a laboratory protocol for the fabrication of tissue valve models mimicking mild and moderate calcific stenosis, for future use in flow studies. ... near-physiologic hemodynamics. The flow loop was driven by a programmable piston pump (Vivitro), and included resistance and compliance units to mimic the characteristics of the systemic vascular tree (Fig. 3A). The system ...

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