Xueying Huang¹, Chun Yang², Jie Zheng³, Pamela K. Woodard³, Dalin Tang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 29-34, 2007, DOI:10.3970/icces.2007.001.029

Abstract Atherosclerotic plaques may rupture without warning and cause acute cardiovascular syndromes such as heart attack and stroke. Accurate identification of plaque components will improve the accuracy and reliability of computational models. In this article, we present a segmentation method using a cluster analysis technique to quantify and classify plaque components from magnetic resonance images (MRI). 3D in vivo and ex vivo multi-contrast (T1-, proton density-, and T2-weighted) MR Images were acquired from a patient of cardiovascular disease. Normal distribution Bayes classifier was performed on ex vivo and in vivo MR Images respectively. The resulting segmentation obtained from cluster analysis showed… More >

Caining Zhang¹, Huaguang Li², Xiaoya Guo³, David Molony⁴, Xiaopeng Guo², Habib Samady⁴, Don P. Giddens^4,5, Lambros Athanasiou⁶, Rencan Nie^2,*, Jinde Cao^3,*, Dalin Tang^1,*,7

Molecular & Cellular Biomechanics, Vol.16, No.2, pp. 153-161, 2019, DOI:10.32604/mcb.2019.06873

Abstract Cardiovascular diseases are closely associated with deteriorating atherosclerotic plaques. Optical coherence tomography (OCT) is a recently developed intravascular imaging technique with high resolution approximately 10 microns and could provide accurate quantification of coronary plaque morphology. However, tissue segmentation of OCT images in clinic is still mainly performed manually by physicians which is time consuming and subjective. To overcome these limitations, two automatic segmentation methods for intracoronary OCT image based on support vector machine (SVM) and convolutional neural network (CNN) were performed to identify the plaque region and characterize plaque components. In vivo IVUS and OCT coronary plaque data from 5… More >

Qingyu Wang¹, Dalin Tang^1,2,*, Gador Canton³, Zheyang Wu², Thomas S. Hatsukami⁴, Kristen L. Billiar⁵, Chun Yuan⁶

Molecular & Cellular Biomechanics, Vol.15, No.4, pp. 189-201, 2018, DOI:10.32604/mcb.2018.04572

Abstract Cardiovascular diseases are closely linked to atherosclerotic plaque development and rupture. Assessment of plaque vulnerability is of fundamental significance to cardiovascular research and disease diagnosis, prevention, treatment and management. Magnetic resonance image (MRI) data of carotid atherosclerotic plaques from 8 patients (5 male, 3 female; age: 62-83, mean=71) were acquired at the University of Washington (UW), Seattle by the Vascular Imaging Laboratory (VIL) with written informed consent obtained. Patient-specific vessel material properties were quantified using Cine MRI data for modeling use. 3D thin-layer models were used to obtain plaque stress and strain for plaque assessment. A stress-based plaque vulnerability index… More >

Chunliu He¹, Jiaqiu Wang², Yuxiang Huang¹, Tongjing Zhu¹, Yuehong Miao¹, Zhiyong Li^1,2*

Molecular & Cellular Biomechanics, Vol.13, No.1, pp. 23-36, 2016, DOI:10.3970/mcb.2016.013.027

Abstract Fibrous cap thickness (FCT) is seen as critical to plaque vulnerability. Therefore, the development of automatic algorithms for the quantification of FCT is for estimating cardiovascular risk of patients. Intravascular optical coherence tomography (IVOCT) is currently the only in vivo imaging modality with which FCT, the critical component of plaque vulnerability, can be assessed accurately. This study was aimed to discussion the correlation between the texture features of OCT images and the FCT in lipid-rich atheroma. Methods: Firstly, a full automatic segmentation algorithm based on unsupervised fuzzy c means (FCM) clustering with geometric constrains was developed to segment the ROIs… More >

Jianhang Du^1,2,3, Liang Wang⁴

Molecular & Cellular Biomechanics, Vol.12, No.4, pp. 249-263, 2015, DOI:10.3970/mcb.2015.012.249

Abstract Growing evidences suggest that long-term enhanced external counterpulsation (EECP) treatment can inhibit the initiation of atherosclerotic lesion by improving the hemodynamic environment in aortas. However, whether this kind procedure will intervene the progression of advanced atherosclerotic plaque remains elusive and causes great concern in its clinical application presently. In the current paper, a pilot study combining animal experiment and numerical simulation was conducted to investigate the acute mechanical stress variations during EECP intervention, and then to assess the possible chronic effects. An experimentally induced hypercholesterolemic porcine model was developed and the basic hemodynamic measurement was performed in vivo before and… More >

Molecular & Cellular Biomechanics, Vol.9, No.1, pp. 77-94, 2012, DOI:10.3970/mcb.2012.009.077

Abstract Image-based computational modeling has been introduced for vulnerable atherosclerotic plaques to identify critical mechanical conditions which may be used for better plaque assessment and rupture predictions. In vivo patient-specific coronary plaque models are lagging due to limitations on non-invasive image resolution, flow data, and vessel material properties. A framework is proposed to combine intravascular ultrasound (IVUS) imaging, biaxial mechanical testing and computational modeling with fluid-structure interactions and anisotropic material properties to acquire better and more complete plaque data and make more accurate plaque vulnerability assessment and predictions. Impact of pre-shrink-stretch process, vessel curvature and high blood pressure on stress, strain,… More >

Biyue Liu^∗, Dalin Tang^†

Molecular & Cellular Biomechanics, Vol.7, No.4, pp. 193-202, 2010, DOI:10.3970/mcb.2010.007.193

Abstract A three dimensional mathematical model with a linear plaque growth function was developed to investigate the geometrical adaptation of atherosclerotic plaques in coronary arteries and study the influences of flow wall shear stress (WSS), blood viscosity and the inlet flow rate on the growth of atherosclerotic plaques using computational plaque growth simulations. The simulation results indicated that the plaque wall thickness at the neck of the stenosis increased at a decreasing rate in the atherosclerosis progression. The simulation results also showed a strong dependence of the plaque wall thickness increase on the blood viscosity and the inlet flow rate. The… 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 >

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 human coronary plaque data to… More >

Jin Suo^*, John N. Oshinski^∗,†, D.P. Giddens^∗,‡

Molecular & Cellular Biomechanics, Vol.5, No.1, pp. 9-18, 2008, DOI:10.3970/mcb.2008.005.009

Abstract Atherosclerotic plaques in human coronary arteries are focal manifestations of systemic disease, and biomechanical factors have been hypothesized to contribute to plaque genesis and localization. We developed a computational fluid dynamics (CFD) model of the ascending aorta and proximal sections of the right and left coronary arteries of a normal human subject using computed tomography (CT) and magnetic resonance imaging (MRI) and determined the pulsatile flow field. Results demonstrate that flow patterns in the ascending aorta contribute to a pro-atherosclerotic flow environment, specifically through localization of low and oscillatory wall shear stress in the neighborhood of coronary orifices. Furthermore, these… More >