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  • Journal article
    Makris GC, Nicolaides AN, Xu XY, Geroulakos Get al., 2010,

    Introduction to the biomechanics of carotid plaque pathogenesis and rupture: review of the clinical evidence

    , BRITISH JOURNAL OF RADIOLOGY, Vol: 83, Pages: 729-735, ISSN: 0007-1285
  • Journal article
    Malkawi AH, Hinchliffe RJ, Xu Y, Holt PJ, Loftus IM, Thompson MMet al., 2010,

    Patient-specific biomechanical profiling in abdominal aortic aneurysm development and rupture

    , JOURNAL OF VASCULAR SURGERY, Vol: 52, Pages: 480-488, ISSN: 0741-5214
  • Journal article
    Rosell DR, Thompson JL, Slifstein M, Xu X, Frankle WG, New AS, Goodman M, Weinstein SR, Laruelle M, Abi-Dargham A, Siever LJet al., 2010,

    Increased Serotonin 2A Receptor Availability in the Orbitofrontal Cortex of Physically Aggressive Personality Disordered Patients

    , BIOLOGICAL PSYCHIATRY, Vol: 67, Pages: 1154-1162, ISSN: 0006-3223
  • Journal article
    Sakalihasan N, Defraigne JO, Xu XY, 2010,

    Response to Comment on "High Levels of 18F-FG Uptake in Aortic Aneurysm Wall are Associated with High Wall Stress"

    , EUROPEAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY, Vol: 39, Pages: 795-796, ISSN: 1078-5884
  • Journal article
    Cheng Z, Tan FPP, Riga CV, Bicknell CD, Hamady MS, Gibbs RGJ, Wood NB, Xu XYet al., 2010,

    Analysis of Flow Patterns in a Patient-Specific Aortic Dissection Model

    , JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, Vol: 132, ISSN: 0148-0731
  • Journal article
    Xu XY, Borghi A, Nchimi A, Leung J, Gomez P, Cheng Z, Defraigne JO, Sakalihasan Net al., 2010,

    High Levels of 18F-FDG Uptake in Aortic Aneurysm Wall are Associated with High Wall Stress

    , EUROPEAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY, Vol: 39, Pages: 295-301, ISSN: 1078-5884
  • Conference paper
    Xu Y, McCormack A, Chester A, Hariri B, Sarathchandra P, Rose MLet al., 2010,

    The Indirect Alloimmune Response Causes Endothelial Dysfunction without Endothelial Replacement after Cardiac Transplantation

    , 30th Annual Meeting and Scientific Sessions of the International-Society-for-Heart-and-Lung-Transplantation, Publisher: ELSEVIER SCIENCE INC, Pages: S129-S129, ISSN: 1053-2498
  • Conference paper
    Malkawi A, Cheng Z, Hinchliffe R, Loftus I, Xu Y, Thompson Met al., 2010,

    Abdominal aortic aneurysm (AAA) wall thickness at regions of high and low wall stress: implications for aortic wall stress computation and rupture prediction

    , 44th Annual Scientific Meeting of the Vascular-Society-of-Great-Britain-and-Ireland, Publisher: WILEY-BLACKWELL, Pages: 15-15, ISSN: 0007-1323
  • Journal article
    Torii R, Keegan J, Wood NB, Dowsey AW, Hughes AD, Yang G-Z, Firmin DN, Thom SA, Xu Yet al., 2010,

    MR image-based geometric and hemodynamic investigation of the right coronary artery withdynamic vessel motion

    , Annals of Biomedical Engineering, Vol: in press

    The aim of this study was to develop a fully subject-specific model of the right coronaryartery (RCA), including dynamic vessel motion, for computational analysis to assess the effects ofcardiac-induced motion on hemodynamics and resulting wall shear stress (WSS). Vascular geometrieswere acquired in the right coronary artery (RCA) of a healthy volunteer using a navigator-gatedinterleaved spiral sequence at 14 time points during the cardiac cycle. A high temporal resolutionvelocity waveform was also acquired in the proximal region. Cardiac-induced dynamic vessel motionwas calculated by interpolating the geometries with an active contour model and a CFD simulationwith fully subject-specific information was carried out using this model. The results showed theexpected variation of vessel radius and curvature throughout the cardiac cycle, and also revealed thatdynamic motion of the right coronary artery consequent to cardiac motion had significant effects oninstantaneous WSS and oscillatory shear index (OSI). Subject specific MRI-based CFD is feasible and, ifscan duration could be shortened, this method may have potential as a non-invasive tool to investigatethe physiological and pathological role of hemodynamics in human coronary arteries.

  • Journal article
    Soloperto G, Keenan NG, Sheppard MN, Ohayon J, Wood NB, Pennell DJ, Mohiaddin RH, XY Xet al., 2010,

    Combined imaging, computational and histological analysis of a ruptured carotid plaque: A patient-specific analysis.

    , Artery Research, Vol: 4, Pages: 59-65

    Background: Rupture of carotid plaques is an important cause of cerebrovascularevents. Several factors, including wall shear stress (WSS), plaque morphology and peak capstress, have been associated with plaque vulnerability. The aim of this study was to investigatethe relationship between these factors in an in vivo human ruptured carotid plaque.Methods: A 74-year-old male presenting with a transient ischemic attack underwent carotidmagnetic resonance imaging (MRI), which indicated a ruptured plaque, followed by carotidendarterectomy, from which plaque histology was assessed. The carotid bifurcation was reconstructedfrom the MRI data, and three-dimensional flow simulations were performed usingcomputational fluid dynamics to determine WSS and related parameters. Plaque vulnerabilitywas assessed using a biomechanical method based on modified Glagov criteria.Results: The plaque rupture was just distal to the site of maximum stenosis in a region of lowWSS, where MRI and histology both demonstrated fibrous cap thinning, a large lipid pool andcalcification in the shoulder region. Plaque vulnerability analysis indicated critically vulnerableplaque at the rupture site by a wide margin.Conclusions: Both low and high WSS have been associated with plaque vulnerability, and highmechanical stress in the cap has been linked to plaque rupture, but these parameters are notroutinely assessed clinically. This study demonstrates a complete analysis by combiningimaging, histology and bio-fluid and biomechanical modelling.

  • Journal article
    Su JW, Gu ZL, Jiao JY, Xu XYet al., 2010,

    Local fixed pivot quadratue method of moment for bubble population balance equation including coalescence and breakage

    , 6TH INTERNATIONAL SYMPOSIUM ON MULTIPHASE FLOW, HEAT MASS TRANSFER AND ENERGY CONVERSION, Vol: 1207, Pages: 610-+, ISSN: 0094-243X
  • Conference paper
    Soloperto G, Keenan N, Sheppard M, Wood N, Pennell DJ, Mohiaddin R, Xu XYet al., 2009,

    A COMBINED IMAGING, COMPUTATIONAL AND HISTOLOGICAL ANALYSIS OF A RUPTURED CAROTID ARTERY

    , Spring Meeting of the British-Society-for-Cardiovascular-Research, Publisher: B M J PUBLISHING GROUP, ISSN: 1355-6037
  • Journal article
    Soloperto G, Keenan NG, Chan C, Sheppard MN, Wood NB, Pennell DJ, Mohiaddin RH, Xu XYet al., 2009,

    Comparison between ruptured and intact atherosclerotic plaques: flow- modelling study of in vivo carotid arteries by cardiovascular magnetic resonance

    , EUROPEAN HEART JOURNAL, Vol: 30, Pages: 763-763, ISSN: 0195-668X
  • Journal article
    Su J, Gu Z, Xu XY, 2009,

    Advances in numerical methods for the solution of population balance equations for disperse phase systems

    , SCIENCE IN CHINA SERIES B-CHEMISTRY, Vol: 52, Pages: 1063-1079, ISSN: 1006-9291
  • Journal article
    Torii R, Wood NB, Hadjiloizou N, Dowsey AW, Wright AR, Hughes AD, Davies J, Francis DP, Mayet J, Yang GZ, Thom SAM, Xu XYet al., 2009,

    Fluid-structure interaction analysis of a patient-specific right coronary artery with physiological velocity and pressure waveforms

    , Communications in Numerical Methods in Engineering, Vol: 25, Pages: 565-580, ISSN: 1069-8299

    Coupled fluid-structure interaction (FSI) analysis of the human right coronary artery (RCA) has been carried out to investigate the effects of wall compliance on coronary hemodynamics. A 3-D model of a stenosed RCA was reconstructed based oil multislice computerized tomography images. A velocity waveform in the proximal RCA and a pressure waveform in the distal RCA of a patient with a severe stenosis were acquired with a catheter delivered wire probe and applied as boundary conditions. The arterial wall was modeled as a Mooncy-Rivlin hyperelastic material. The predicted maximum wall displacement (3.85 mm) was comparable with the vessel diameter (similar to 4 mm), but the diameter variation was much smaller, 0.134 mm at the stenosis and 0.486 mm in the distal region. Comparison of the computational results between the FSI and rigid-wall models showed that the instantaneous wall shear stress (WSS) distributions were affected by diameter variation in the arterial walk increasing systolic blood pressure dilated the vessel and consequently lowered WSS, whereas the opposite occurred When pressure started to decrease. However. file effects of wall compliance on time-averaged WSS (TAWSS) and oscillatory shear index (OSI) were insignificant (4.5 and 2.7% difference in maximum TAWSS and OSI. respectively). Copyright (C) 2009 John Wiley & Sons, Ltd.

  • Journal article
    Giannakoulas G, Dimopoulos K, Xu XY, 2009,

    Modelling in congenital heart disease. Art or science?

    , INTERNATIONAL JOURNAL OF CARDIOLOGY, Vol: 133, Pages: 141-144, ISSN: 0167-5273
  • Journal article
    Torii R, Wood NB, Hadjiloizou N, Dowsey AW, Wright AR, Hughes AD, Davies J, Francis DP, Mayet J, Yang GZ, Thom SAM, Xu XYet al., 2009,

    Stress phase angle depicts differences in coronary artery hemodynamics due to changes in flow and geometry after percutaneous coronary intervention

    , American Journal of Physiology - Heart and Circulatory Physiology, Vol: 296, Pages: H765-H776, ISSN: 0363-6135

    Torii R, Wood NB, Hadjiloizou N, Dowsey AW, Wright AR, Hughes AD, Davies J, Francis DP, Mayet J, Yang G, Thom SA, Xu XY. Stress phase angle depicts differences in coronary artery hemodynamics due to changes in flow and geometry after percutaneous coronary intervention. Am J Physiol Heart Circ Physiol 296: H765-H776, 2009. First published January 16, 2009; doi:10.1152/ajpheart.01166.2007.-The effects of changes in flow velocity waveform and arterial geometry before and after percutaneous coronary intervention (PCI) in the right coronary artery (RCA) were investigated using computational fluid dynamics. An RCA from a patient with a stenosis was reconstructed based on multislice computerized tomography images. A nonstenosed model, simulating the same RCA after PCI, was also constructed. The blood flows in the RCA models were simulated using pulsatile flow waveforms acquired with an intravascular ultrasound-Doppler probe in the RCA of a patient undergoing PCI. It was found that differences in the waveforms before and after PCI did not affect the time-averaged wall shear stress and oscillatory shear index, but the phase angle between pressure and wall shear stress on the endothelium, stress phase angle (SPA), differed markedly. The median SPA was -63.9 degrees (range, -204 degrees to -10.0 degrees) for the pre-PCI state, whereas it was 10.4 degrees (range, -71.1 degrees to 25.4 degrees) in the post-PCI state, i.e., more asynchronous in the pre-PCI state. SPA has been reported to influence the secretion of vasoactive molecules (e. g., nitric oxide, PGI(2), and endothelin-1), and asynchronous SPA (approximate to -180 degrees) is proposed to be proatherogenic. Our results suggest that differences in the pulsatile flow waveform may have an important influence on atherogenesis, although associated with only minor changes in the time-averaged wall shear stress and oscillatory shear index. SPA may be a useful indicator in predicting sites prone to atherosclerosis.

  • Journal article
    Gu Z, Su J, Jiao J, Xu XYet al., 2009,

    Simulation of micro-behaviors including nucleation, growth, and aggregation in particle system

    , SCIENCE IN CHINA SERIES B-CHEMISTRY, Vol: 52, Pages: 241-248, ISSN: 1006-9291
  • Journal article
    Sun N, Torii R, Wood NB, Hughes AD, Thom SAM, Xu XYet al., 2009,

    Computational Modeling of LDL and Albumin Transport in an In Vivo CT Image-Based Human Right Coronary Artery

    , JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, Vol: 131, ISSN: 0148-0731
  • Journal article
    Sun N, Leung JH, Wood NB, Hughes AD, Thom SA, Cheshire NJ, Xu XYet al., 2009,

    Computational analysis of oxygen transport in a patient-specific model of abdominal aortic aneurysm with intraluminal thrombus

    , BRITISH JOURNAL OF RADIOLOGY, Vol: 82, Pages: S18-S23, ISSN: 0007-1285

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