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Influence of the accuracy of angiography-based reconstructions on velocity and wall shear stress computations in coronary bifurcations: A phantom study

Schrauwen, J.T.C. (author), Karanasos, A. (author), Van Ditzhuijzen, N.S. (author), Aben, J.P. (author), Van der Steen, A.F.W. (author), Wentzel, J.J. (author), Gijsen, F.J.H. (author)

Wall shear stress (WSS) plays a key role in the onset and progression of atherosclerosis in human coronary arteries. Especially sites with low and oscillating WSS near bifurcations have a higher propensity to develop atherosclerosis. WSS computations in coronary bifurcations can be performed in angiography-based 3D reconstructions. It is...

journal article 2015

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Computational reuse optimisation for stadium design

Van der Steen, J. (author), Coenders, J.L. (author), Pasterkamp, S. (author), Rolvink, A. (author), Van Steekelenburg, J. (author)

This paper presents a proof of concept study into a computational strategy for reusing structural stadium elements. The strategy goal is overcoming the reuse design strain through implementation of a genetic algorithm. This algorithm is calibrated to search for a structural frame configuration, while using a reusable element set, meeting floor...

conference paper 2015

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A computer-simulation study on the effects of MRI voxel dimensions on carotid plaque lipid-core and fibrous cap segmentation and stress modeling

Nieuwstadt, H.A. (author), Kassar, Z.A.M. (author), Van der Lugt, A. (author), Breeuwer, M. (author), Van der Steen, A.F.W. (author), Wentzel, J.J. (author), Gijsen, F.J.H. (author)

Background The benefits of a decreased slice thickness and/or in-plane voxel size in carotid MRI for atherosclerotic plaque component quantification accuracy and biomechanical peak cap stress analysis have not yet been investigated in detail because of practical limitations. Methods In order to provide a methodology that allows such an...

journal article 2015

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Photoacoustic imaging of carotid artery atherosclerosis

Kruizinga, P. (author), Springeling, G. (author), Van Soest, G. (author), Van der Steen, A.F.W. (author), De Jong, N. (author), Robertus, J.L. (author), Van der Lugt, A. (author)

We introduce a method for photoacoustic imaging of the carotid artery, tailored toward detection of lipid-rich atherosclerotic lesions. A common human carotid artery was obtained at autopsy, embedded in a neck mimicking phantom and imaged with a multimodality imaging system using interstitial illumination. Light was delivered through a 1.25-mm...

journal article 2014

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Atherosclerotic plaque fibrous cap assessment under an oblique scan plane orientation in carotid MRI

Nieuwstadt, H.A. (author), Van der Lugt, A. (author), Kassar, Z.A.M. (author), Breeuwer, M. (author), Van der Steen, A.F.W. (author), Gijsen, F.J.H. (author)

Carotid magnetic resonance imaging (MRI) is used to noninvasively assess atherosclerotic plaque fibrous cap (FC) status, which is closely related to ischemic stroke. Acquiring anisotropic voxels improves in-plane visualization, however, an oblique scan plane orientation could then obscure a FC (i.e., contrast below the noise level) and thus...

journal article 2014

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Intravascular Photoacoustic Imaging: A New Tool for Vulnerable Plaque Identification

Jansen, K. (author), Van Soest, G. (author), Van der Steen, A.F.W. (author)

The vulnerable atherosclerotic plaque is believed to be at the root of the majority of acute coronary events. Even though the exact origins of plaque vulnerability remain elusive, the thin-cap fibroatheroma, characterized by a lipid-rich necrotic core covered by a thin fibrous cap, is considered to be the most prominent type of vulnerable plaque...

journal article 2014

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Mapping Intravascular Ultrasound Controversies in Interventional Cardiology Practice

Maresca, D. (author), Adams, S. (author), Maresca, B. (author), Van der Steen, A.F.W. (author)

Intravascular ultrasound is a catheter-based imaging modality that was developed to investigate the condition of coronary arteries and assess the vulnerability of coronary atherosclerotic plaques in particular. Since its introduction in the clinic 20 years ago, use of intravascular ultrasound innovation has been relatively limited. Intravascular...

journal article 2014

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Effect of temperature and fixation on the optical properties of atherosclerotic tissue: A validation study of an ex-vivo whole heart cadaveric model

Gnanadesigan, M. (author), Van Soest, G. (author), White, S. (author), Scoltock, S. (author), Ughi, G.J. (author), Baumbach, A. (author), Van der Steen, A.F.W. (author), Regar, E. (author), Johnson, T.W. (author)

Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model for the effect of temperature and tissue...

journal article 2014

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Photoacoustic imaging of human coronary atherosclerosis in two spectral bands

Jansen, K. (author), Wu, M. (author), Van der Steen, A.F.W. (author), Van Soest, G. (author)

Spectroscopic intravascular photoacoustic imaging (sIVPA) has shown promise to detect and distinguish lipids in atherosclerotic plaques. sIVPA generally utilizes one of the two high absorption bands in the lipid absorption spectrum at 1.2 ?m and 1.7 ?m. Specific absorption signatures of various lipid compounds within the bands in either...

journal article 2014

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Spectroscopic intravascular photoacoustic imaging of lipids in atherosclerosis

Jansen, K. (author), Van der Steen, A.F.W. (author), Wu, M. (author), Van Beusekom, H.M.M. (author), Springeling, G. (author), Li, X. (author), Zhou, Q. (author), Shung, K.K. (author), De Kleijn, D.P.V. (author), Van Soest, G. (author)

The natural history of atherosclerosis is marked by changes in the lipid biochemistry in the diseased arterial wall. As lesions become more vulnerable, different cholesterol species accumulate in the plaque. Understanding unstable atherosclerosis as a pharmacological and interventional therapeutic target requires chemically specific imaging of...

journal article 2014

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Quality of visual sewer inspection data: The need for a new coding system?! (poster)

Dirksen, J. (author), Van der Steen, A. (author), Langeveld, J.G. (author), Clemens, F.H.L.R. (author)

Previous research learned that the reproducibility of visual sewer inspection data is poor (Dirksen et al.). Further research by Arjan et al. showed that the applied coding system has a major influence on the reproducibility. The aim of this study was to give relevant suggestions to improve the quality by defining defects that are in the current...

conference paper 2013

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Lipid detection in atherosclerotic human coronaries by spectroscopic intravascular photoacoustic imaging

Jansen, K. (author), Wu, M. (author), Van der Steen, A.F.W. (author), Van Soest, G. (author)

The presence of lipids in atherosclerotic coronary lesions is an important determinant of their potential to trigger acute coronary events. Spectroscopic intravascular photoacoustic imaging (sIVPA) has the potential to automatically detect lipids in atherosclerotic lesions. For realtime in vivo imaging, limiting the number of excitation...

journal article 2013

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Intravascular ultrasound chirp imaging

Maresca, D. (author), Jansen, K. (author), Renaud, G. (author), Van Soest, G. (author), Li, X. (author), Zhou, Q. (author), De Jong, N. (author), Shung, K.K. (author), Van der Steen, A.F.W. (author)

We demonstrate the feasibility of intravascular ultrasound (IVUS) chirp imaging as well as chirp reversal ultrasound contrast imaging at intravascular ultrasound frequency. Chirp excitations were emitted with a 34?MHz single crystal intravascular transducer and compared to conventional Gaussian-shaped pulses of equal acoustic pressure. The...

journal article 2012

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Governing the transition to e-mobility: Small steps towards a giant leap

Van Deventer, A.P. (author), Van der Steen, M.A. (author), De Bruijn, J.A. (author), Van Twist, M.J.W. (author), Heuvelhof, E.F. (author), Haynes, K.E. (author)

report 2011

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Comparison of fundamental, second harmonic, and superharmonic imaging: A simulation study

Van Neer, P.L.M.J. (author), Danilouchkine, M.G. (author), Verweij, M.D. (author), Demi, L. (author), Voormolen, M.M. (author), Van der Steen, A.F.W. (author), De Jong, N. (author)

In medical ultrasound, fundamental imaging (FI) uses the reflected echoes from the same spectral band as that of the emitted pulse. The transmission frequency determines the trade-off between penetration depth and spatial resolution. Tissue harmonic imaging (THI) employs the second harmonic of the emitted frequency band to construct images....

journal article 2011

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Approaches towards a smart & speedy improvement of the in series developed post war housing stock

Van Hal, A. (author), Van der Steen, L. (author), Van der Werf, E. (author)

One third of the current housing stock in The Netherlands dates from the sixties and seventies and a large part of these dwellings are fairly similar (because they were built in series). There is a high need for smart and speedy renovation methods, to improve technical, energy and cost efficiency of renovation projects as well as to limit...

conference paper 2011

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Approaches towards a smart and speedy improvement of the in series developed post war housing stock

Van Hal, A. (author), Van der Steen, L. (author), Van der Werf, E. (author)

One third of the current housing stock in The Netherlands dates from the sixties and seventies and a large part of these dwellings are fairly similar (because they were built in series). There is a high need for smart and speedy renovation methods, to improve technical, energy and cost efficiency of renovation projects as well as to limit...

conference paper 2011

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Effects of intima stiffness and plaque morphology on peak cap stress

Akyildiz, A.C. (author), Speelman, L. (author), Van Brummelen, H. (author), Gutiérrez, M.A. (author), Virmani, R. (author), Van der Lugt, A. (author), Van der Steen, A.F.W. (author), Wentzel, J.J. (author), Gijsen, F.J.H. (author)

Background: Rupture of the cap of a vulnerable plaque present in a coronary vessel may cause myocardial infarction and death. Cap rupture occurs when the peak cap stress exceeds the cap strength. The mechanical stress within a cap depends on the plaque morphology and the material characteristics of the plaque components. A parametric study was...

journal article 2011

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Flow separation control by off surface elements

Veldhuis, L.L.M. (author), Van der Steen, M. (author)

Comparative wind tunnel experiments were performed on passive flow separation control on a at plate model equipped with a flap. The purpose of these tests was to investigate the flow control capabilities of off-surface mounted elements. A comparison was made of delta-shaped vortex generators of 1 to 1/3 boundary layer height and cylinders close...

conference paper 2010

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Time-Dependent Polynomial Chaos

Gerritsma, M.I. (author), Vos, P. (author), Van der Steen, J.B. (author)

conference paper 2008