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Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics

Manchester, Emily Louise (author), Pirola, S. (author), Pirola, Sergio (author), Mastroiacovo, Giorgio (author), Polvani, Gianluca (author), Pontone, Gianluca (author), Xu, Xiao Yun (author)

Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects...

journal article 2024

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Vector-flow imaging of slowly moving ex vivo blood with photoacoustics and pulse-echo ultrasound

Smith, Caitlin (author), Shepherd, Jami (author), Renaud, G.G.J. (author), van Wijk, Kasper (author)

We present a technique called photoacoustic vector-flow (PAVF) to quantify the speed and direction of flowing optical absorbers at each pixel from acoustic-resolution PA images. By varying the receiving angle at each pixel in post-processing, we obtain multiple estimates of the phase difference between consecutive frames. These are used to...

journal article 2024

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Flow patterns in ascending aortic aneurysms: Determining the role of hypertension using phase contrast magnetic resonance and computational fluid dynamics

Ramaekers, M. J.F.G. (author), van der Vlugt, I.B. (author), Westenberg, J. J.M. (author), Perinajová, R. (author), Lamb, H. J. (author), Wildberger, J. E. (author), Kenjeres, S. (author), Schalla, S. (author)

Thoracic aortic aneurysm (TAA) is a local dilation of the thoracic aorta. Although universally used, aneurysm diameter alone is a poor predictor of major complications such as rupture. There is a need for better biomarkers for risk assessment that also reflect the aberrant flow patterns found in TAAs. Furthermore, hypertension is often...

journal article 2024

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Improved reproducibility for myocardial ASL: Impact of physiological and acquisition parameters

Bozic, M. (author), Rapacchi, Stanislas (author), Tao, Q. (author), Pierce, Iain (author), Thornton, George (author), Nitsche, Christian (author), Treibel, Thomas A. (author), Schad, Lothar R. (author), Weingärtner, S.D. (author)

Purpose: To investigate and mitigate the influence of physiological and acquisition-related parameters on myocardial blood flow (MBF) measurements obtained with myocardial Arterial Spin Labeling (myoASL). Methods: A Flow-sensitive Alternating Inversion Recovery (FAIR) myoASL sequence with bSSFP and spoiled GRE (spGRE) readout is investigated...

journal article 2023

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Improved reliability of perfusion estimation in dynamic susceptibility contrast MRI by using the arterial input function from dynamic contrast enhanced MRI

Tseng, C. (author), Jaspers, Jaap (author), Romero, Alejandra Mendez (author), Wielopolski, Piotr (author), Smits, M. (author), van Osch, Matthias J.P. (author), Vos, F.M. (author)

The arterial input function (AIF) plays a crucial role in estimating quantitative perfusion properties from dynamic susceptibility contrast (DSC) MRI. An important issue, however, is that measuring the AIF in absolute contrast-agent concentrations is challenging, due to uncertainty in relation to the measured (Formula presented.) -weighted...

journal article 2023

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Fluid-structure interactions of peripheral arteries using a coupled in silico and in vitro approach

Schoenborn, S. (author), Lorenz, T. (author), Kuo, K. (author), Fletcher, D. F. (author), Woodruff, M. A. (author), Pirola, S. (author), Allenby, M. C. (author)

Vascular compliance is considered both a cause and a consequence of cardiovascular disease and a significant factor in the mid- and long-term patency of vascular grafts. However, the biomechanical effects of localised changes in compliance cannot be satisfactorily studied with the available medical imaging technologies or surgical simulation...

journal article 2023

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Single-Sided Ultrasound Imaging of the Bone Cortex: Anatomy, Tissue Characterization and Blood Flow

Renaud, G.G.J. (author), Salles, Sébastien (author)

In this chapter, we first review the reasons why conventional ultrasonography fails to image the interior of bones. Next we show our recent work on imaging a cortical bone layer with ultrasound. Revealing the shape of the cortex of a bone, in particular its thickness, is of interest for evaluating bone strength. In addition we describe how...

journal article 2022

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High-Resolution Free-Breathing Quantitative First-Pass Perfusion Cardiac MR Using Dual-Echo Dixon With Spatio-Temporal Acceleration

Tourais, Joao (author), Scannell, Cian M. (author), Schneider, Torben (author), Alskaf, Ebraham (author), Crawley, Richard (author), Bosio, Filippo (author), Sanchez-Gonzalez, Javier (author), Doneva, Mariya (author), Schülke, Christophe (author)

Introduction: To develop and test the feasibility of free-breathing (FB), high-resolution quantitative first-pass perfusion cardiac MR (FPP-CMR) using dual-echo Dixon (FOSTERS; Fat-water separation for mOtion-corrected Spatio-TEmporally accelerated myocardial peRfuSion). Materials and Methods: FOSTERS was performed in FB using a dual...

journal article 2022

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Modelling collateral flow and thrombus permeability during acute ischaemic stroke

Padmos, R.M. (author), Arrarte Terreros, Nerea (author), Józsa, Tamás I. (author), Závodszky, Gábor (author), Marquering, Henk A. (author), Majoie, Charles B.L.M. (author), Payne, Stephen J. (author), Hoekstra, Alfons G. (author)

The presence of collaterals and high thrombus permeability are associated with good functional outcomes after an acute ischaemic stroke. We aim to understand the combined effect of the collaterals and thrombus permeability on cerebral blood flow during an acute ischaemic stroke. A cerebral blood flow model including the leptomeningeal...

journal article 2022

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Independent Component Analysis Filter for Small Vessel Contrast Imaging During Fast Tissue Motion

Wahyulaksana, G. (author), Wei, Luxi (author), Schoormans, Jasper (author), Voorneveld, J.D. (author), van der Steen, A.F.W. (author), de Jong, N. (author), Vos, H.J. (author)

Suppressing tissue clutter is an essential step in blood flow estimation and visualization, even when using ultrasound contrast agents. Blind source separation (BSS)-based clutter filter for high-framerate ultrasound imaging has been reported to perform better in tissue clutter suppression than the conventional frequency-based wall filter and...

journal article 2022

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Optimization of Microbubble Concentration and Acoustic Pressure for Left Ventricular High Frame Rate EchoPIV in Patients

Voorneveld, J.D. (author), Keijzer, L.B.H. (author), Strachinaru, Mihai (author), Bowen, Daniel J. (author), Mutluer, Ferit O. (author), van der Steen, A.F.W. (author), Ten Cate, Folkert (author), de Jong, N. (author), Vos, H.J. (author), Van den Bosch, Annemien E. (author), Bosch, Johan G. (author)

High-frame-rate (HFR) echo-particle image velocimetry (echoPIV) is a promising tool for measuring intracardiac blood flow dynamics. In this study, we investigate the optimal ultrasound contrast agent (UCA: SonoVue) infusion rate and acoustic output to use for HFR echoPIV (PRF = 4900 Hz) in the left ventricle (LV) of patients. Three infusion...

journal article 2021

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Echo planar imaging–induced errors in intracardiac 4D flow MRI quantification

Westenberg, Jos J.M. (author), van Assen, Hans C. (author), van den Boogaard, Pieter J. (author), Goeman, Jelle J. (author), Saaid, Hicham (author), Voorneveld, J.D. (author), Bosch, Johan (author), Kenjeres, S. (author), Claessens, Tom (author)

Purpose: To assess errors associated with EPI-accelerated intracardiac 4D flow MRI (4DEPI) with EPI factor 5, compared with non-EPI gradient echo (4DGRE). Methods: Three 3T MRI experiments were performed comparing 4DEPI to 4DGRE: steady flow through straight tubes, pulsatile flow in a left-ventricle phantom, and intracardiac flow in 10...

journal article 2021

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Acceleration Magnification for Visualising Blood Flow Pulsation in the Skin

Verzijl, Matthijs (author)

While millions of people world wide suffer from arterial diseases, such as peripheral arterial disease, there are a limited number of methods that can be used to diagnose and track these diseases which are also easy, quick and non-invasive. <br/><br/>This work focuses on what is needed to improve diagnosing and tracking of peripheral arterial...

master thesis 2020

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Combining MRI blood flow data with one-dimensional blood flow models to perform patient-speciffic noninvasive pressure prediction

Hamel, David (author)

In this thesis, the behaviour and application of a one-dimensional model describing blood flow through compliant vessels is investigated. The one-dimensional model is derived using the physical laws of conservation of momentum and conservation of mass and uses a Finite Volume Method in combination with a high resolution flux difference splitting...

bachelor thesis 2020

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Two-Dimensional Blood Flow Estimation in the Brain with Ultrafast Ultrasound

Kumar, Karishma (author)

Detailed imaging of blood flow may improve the understanding of brain functions. The state-of-the-art non-invasive flow imaging of the brain is limited to a one-dimensional Doppler setting. We propose a method to estimate the two-dimensional flow vector in the fine vascular network of the brain by using a speckle tracking technique. The...

master thesis 2020

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Pixel-wise assessment of cardiovascular magnetic resonance first-pass perfusion using a cardiac phantom mimicking transmural myocardial perfusion gradients

Milidonis, Xenios (author), Nazir, Muhummad Sohaib (author), Schneider, Torben (author), Capstick, Myles (author), Drost, S. (author), Kok, Gertjan (author), Pelevic, Nikola (author), Poelma, C. (author), Schaeffter, Tobias (author), Chiribiri, Amedeo (author)

Purpose: Cardiovascular magnetic resonance first-pass perfusion for the pixel-wise detection of coronary artery disease is rapidly becoming the clinical standard, yet no widely available method exists for its assessment and validation. This study introduces a novel phantom capable of generating spatially dependent flow values to enable...

journal article 2020

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The costs and benefits of estimating T₁ of tissue alongside cerebral blood flow and arterial transit time in pseudo-continuous arterial spin labeling

Bladt, Piet (author), den Dekker, A.J. (author), Clement, Patricia (author), Achten, Eric (author), Sijbers, Jan (author)

Multi-post-labeling-delay pseudo-continuous arterial spin labeling (multi-PLD PCASL) allows for absolute quantification of the cerebral blood flow (CBF) as well as the arterial transit time (ATT). Estimating these perfusion parameters from multi-PLD PCASL data is a non-linear inverse problem, which is commonly tackled by fitting the single...

journal article 2019

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Turbulence in Aneurysms: Numerical Investigation in Abdominal Aortic Aneurysms

Rawat, Digvijay (author)

An aneurysm refers to the local dilation or ballooning of a blood vessel and if left unchecked, almost every aneurysm continues to grow in size until it eventually ruptures. The abdominal aorta is the most common location for an aneurysm to form and an abdominal aortic aneurysm (AAA) can turn lethal in the event of rupture. Since the current...

master thesis 2017

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One-dimensional blood flow modelling in the human arterial system with Finite Volume Methods

Rozendaal, Marco (author)

In this thesis, it is investigated how the blood flow changes in different physiological situations, using a one-dimensional model, that describes the blood flow in compliant vessels. The one-dimensional model, that describes the blood flow, is derived based on the physical laws of conservation of momentum and conservation of mass. A high...

bachelor thesis 2017

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Classification of hemodynamically significant stenoses from dynamic CT perfusion and CTA myocardial territories

Giordano, M. (author), Poot, D.H.J. (author), Coenen, Adriaan (author), van Walsum, Theo (author), Tezza, Michela (author), Nieman, Koen (author), Niessen, W.J. (author)

Purpose<br/>Myocardial blood flow (MBF) obtained by dynamic CT perfusion (CTP) has been recently introduced to assess hemodynamic significance of coronary stenosis in coronary artery disease. The diagnostic performance of dynamic CTP MBF is limited due to subjective interpretation of MBF maps and MBF variations caused by physiological,...

journal article 2017