Chun Yang^1,2, Dalin Tang^2,3 Satya Atluri⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.1, pp. 51-76, 2010, DOI:10.3970/cmes.2010.057.051

Abstract Cardiovascular disease (CVD) is becoming the number one cause of death worldwide. Atherosclerotic plaque rupture and progression are closely related to most severe cardiovascular syndromes such as heart attack and stroke. Mechanisms governing plaque rupture and progression are not well understood. A computational procedure based on three-dimensional meshless generalized finite difference (MGFD) method and serial magnetic resonance imaging (MRI) data was introduced to quantify patient-specific carotid atherosclerotic plaque growth functions and simulate plaque progression. Participating patients were scanned three times (T1, T2, and T3, at intervals of about 18 months) to obtain plaque progression data.… More >

Dalin Tang¹, Chun Yang^1,2, Tal Geva^3,4, Glenn Gaudette⁴, and Pedro J. del Nido⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.2, pp. 113-130, 2010, DOI:10.3970/cmes.2010.056.113

Abstract Right and left ventricle (RV/LV) combination models with three different patch materials (Dacron scaffold, treated pericardium, and contracting myocardium), two-layer construction, fiber orientation, and active anisotropic material properties were introduced to evaluate the effects of patch materials on RV function. A material-stiffening approach was used to model active heart contraction. Cardiac magnetic resonance (CMR) imaging was performed to acquire patient-specific ventricular geometries and cardiac motion from a patient with severe RV dilatation due to pulmonary regurgitation needing RV remodeling and pulmonary valve replacement operation. Computational models were constructed and solved to obtain RV stroke volume,… More >

Xueying Huang^*, Chun Yang^†, Chun Yuan^‡, Fei Liu^‡, Gador Canton^‡, Jie Zheng^§, Pamela K. Woodard^§, Gregorio A. Sicard^¶, Dalin Tang^||

Molecular & Cellular Biomechanics, Vol.6, No.2, pp. 121-134, 2009, DOI:10.3970/mcb.2009.006.121

Abstract Image-based computational models for atherosclerotic plaques have been developed to perform mechanical analysis to quantify critical flow and stress/strain conditions related to plaque rupture which often leads directly to heart attack or stroke. An important modeling issue is how to determine zero stress state from in vivo plaque geometries. This paper presents a method to quantify human carotid artery axial and inner circumferential shrinkages by using patient-specific ex vivo and in vivo MRI images. A shrink-stretch process based on patient-specific in vivo plaque morphology and shrinkage data was introduced to shrink the in vivo geometry first to find the zero-stress… More >

A. L. Aguilar-Shea, A. M. Molino-González, C. Gallardo-Mayo, J. M. Pedradas-Navas

Canadian Journal of Urology, Vol.15, No.4, pp. 4188-4190, 2008

Abstract Spinal epidural abscess is an infectious disorder with high morbidity and mortality rates, which is often associated with delayed diagnosis. We report a case of a 73-year-old man with cervical pyogenic spondylodiscitis complicated with epidural abscess following a prostatic biopsy. Clinical presentation included fever, malaise, neck rigidity in all axes, minor paresis of the right arm, and gait ataxia. A cervical vertebral magnetic resonance imaging (MRI) scan showed pyogenic spondylodiscitis with an epidural abscess. Blood, urine, and cerebrospinal fl uid cultures were sterile. The patient was treated with intravenous vancomycin, metronidazole, and ceftazidime for 4 More >

Chun Yang^∗,†, Dalin Tang^∗,‡, Shunichi Kobayashi^§, Jie Zheng^¶, Pamela K. Woodard^§, Zhongzhao Teng^*, Richard Bach^||, David N. Ku^∗∗

Molecular & Cellular Biomechanics, Vol.5, No.4, pp. 259-274, 2008, DOI:10.3970/mcb.2008.005.259

Abstract Many acute cardiovascular syndromes such as heart attack and stroke are caused by atherosclerotic plaque ruptures which often happen without warning. MRI-based models with fluid-structure interactions (FSI) have been introduced to perform flow and stress/strain analysis for atherosclerotic plaques and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. In this paper, cyclic bending was added to 3D FSI coronary plaque models for more accurate mechanical predictions. Curvature variation was prescribed using the data of a human left anterior descending (LAD) coronary artery. Five computational models were constructed based on ex vivo MRI… More >

Chun Yang¹, Dalin Tang², Chun Yuan³, William Kerwin², Fei Liu³, Gador Canton³, Thomas S. Hatsukami^3,4, Satya Atluri⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.2, pp. 95-108, 2008, DOI:10.3970/cmes.2008.028.095

Abstract Atherosclerotic plaque rupture and progression have been the focus of intensive investigations in recent years. Plaque rupture is closely related to most severe cardiovascular syndromes such as heart attack and stroke. A computational procedure based on meshless generalized finite difference (MGFD) method and serial magnetic resonance imaging (MRI) data was introduced to quantify patient-specific carotid atherosclerotic plaque growth functions and simulate plaque progression. Participating patients were scanned three times (T₁,T₂, and T₃, at intervals of about 18 months) to obtain plaque progression data. Vessel wall thickness (WT) changes were used as the measure for plaque progression.… More >

Kalyan C. Latchamsetty, Lester S. Borden, Jr, Christopher R. Porter, Marc Lacrampe, Matthew Vaughan, Eugene Lin, Neal Conti, Jonathan L. Wright, John M. Corman

Canadian Journal of Urology, Vol.14, No.1, pp. 3429-3434, 2007

Abstract Introduction: Accurate clinical staging is critical in guiding treatment for patients with prostate adenocarcinoma. Endorectal magnetic resonance imaging (MRI) has been advocated to improve staging accuracy. In order to assess the learning curve for endorectal MRI interpretation, we compared two cohorts of patients with high-risk prostate who underwent endorectal MRI at a center with limited prior exposure to this imaging modality.
Materials and methods: Data for all patients who received a preoperative endorectal MRI followed by radical prostatectomy were prospectively collected. MRI was performed in patients with a high level of suspicion for extracapsular disease based on… More >

Chein-Shan Liu¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.2, pp. 57-68, 2007, DOI:10.3970/icces.2007.003.057

Abstract A new method is developed to solve the interior and exterior Dirichlet problems for the two-dimensional Laplace equation, namely the meshless regularized integral equation method (MRIEM), which consists of three parts: Fourier series expansion, the second kind Fredholm integral equation and an analytically regularized solution of the unknown boundary condition on an artificial circle. We find that the new method is powerful even for the problem with very complex boundary shape and with boundary noise. More >

Dalin Tang^*, Chun Yang^†, Tal Geva^‡,§, Pedro J. del Nido^¶

Molecular & Cellular Biomechanics, Vol.4, No.3, pp. 159-176, 2007, DOI:10.3970/mcb.2007.004.159

Abstract A single-layer isotropic patient-specific right/left ventricle and patch (RV/LV/Patch) combination model with fluid-structure interactions (FSI) was introduced in our previous papers to evaluate and optimize human pulmonary valve replacement/insertion (PVR) surgical procedure and patch design. In this paper, an active anisotropic model with two-layer structure for ventricle wall and tissue fiber orientation was introduced to improve previous isotropic model for more accurate assessment of RV function and potential application in PVR surgery and patch design. A material-stiffening approach was used to model active heart contraction. The computational models were used to conduct ``virtual (computational)'' surgeries More >

Chun Yang¹, Dalin Tang², Chun Yuan³, Thomas S. Hatsukami⁴, Jie Zheng⁵, Pamela K. Woodard⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.3, pp. 233-246, 2007, DOI:10.3970/cmes.2007.019.233

Abstract It has been recognized that fluid-structure interactions (FSI) play an important role in cardiovascular disease initiation and development. However, in vivo MRI multi-component FSI models for human carotid atherosclerotic plaques with bifurcation and quantitative comparisons of FSI models with fluid-only or structure-only models are currently lacking in the literature. A 3D non-Newtonian multi-component FSI model based on in vivo/ex vivo MRI images for human atherosclerotic plaques was introduced to investigate flow and plaque stress/strain behaviors which may be related to plaque progression and rupture. Both artery wall and plaque components were assumed to be hyperelastic,… More >