scholarly journals 3D MRI-Based Anisotropic FSI Models With Cyclic Bending for Human Coronary Atherosclerotic Plaque Mechanical Analysis

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Dalin Tang ◽  
Chun Yang ◽  
Shunichi Kobayashi ◽  
Jie Zheng ◽  
Pamela K. Woodard ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Vulnerability Assessment ◽  
Computational Models ◽  
Plaque Rupture ◽  
Maximum Velocity ◽  
Coronary Plaque ◽  
Plaque Vulnerability ◽  
Stress Strain ◽  
Axial Stretch ◽  
Cyclic Bending

Heart attack and stroke are often caused by atherosclerotic plaque rupture, which happens without warning most of the time. Magnetic resonance imaging (MRI)-based atherosclerotic plaque models with fluid-structure interactions (FSIs) have been introduced to perform flow and stress/strain analysis and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. For coronary arteries, cyclic bending associated with heart motion and anisotropy of the vessel walls may have significant influence on flow and stress/strain distributions in the plaque. FSI models with cyclic bending and anisotropic vessel properties for coronary plaques are lacking in the current literature. In this paper, cyclic bending and anisotropic vessel properties were added to 3D FSI coronary plaque models so that the models would be more realistic for more accurate computational flow and stress/strain predictions. Six computational models using one ex vivo MRI human coronary plaque specimen data were constructed to assess the effects of cyclic bending, anisotropic vessel properties, pulsating pressure, plaque structure, and axial stretch on plaque stress/strain distributions. Our results indicate that cyclic bending and anisotropic properties may cause 50–800% increase in maximum principal stress (Stress-P1) values at selected locations. The stress increase varies with location and is higher when bending is coupled with axial stretch, nonsmooth plaque structure, and resonant pressure conditions (zero phase angle shift). Effects of cyclic bending on flow behaviors are more modest (9.8% decrease in maximum velocity, 2.5% decrease in flow rate, 15% increase in maximum flow shear stress). Inclusion of cyclic bending, anisotropic vessel material properties, accurate plaque structure, and axial stretch in computational FSI models should lead to a considerable improvement of accuracy of computational stress/strain predictions for coronary plaque vulnerability assessment. Further studies incorporating additional mechanical property data and in vivo MRI data are needed to obtain more complete and accurate knowledge about flow and stress/strain behaviors in coronary plaques and to identify critical indicators for better plaque assessment and possible rupture predictions.

3D In Vivo IVUS-Based Anisotropic FSI Models With Cyclic Bending for Human Coronary Atherosclerotic Plaque Mechanical Analysis

2009 ◽  
Author(s):  
Dalin Tang ◽  
Chun Yang ◽  
Jie Zheng ◽  
Pamela K. Woodard ◽  
Kristen Billiar ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Computational Models ◽  
Material Model ◽  
3D Models ◽  
Mechanical Analysis ◽  
Intraplaque Hemorrhage ◽  
Plaque Vulnerability ◽  
Cardiovascular Research ◽  
Cyclic Bending

Assessing atherosclerotic plaque vulnerability based on limited in vivo patient data has been a major challenge in cardiovascular research and clinical practice. Considerable advances in medical imaging technology have been made in recent years to identify vulnerable atherosclerotic carotid plaques in vivo with information about plaque components including lipid-rich necrotic pools, calcification, intraplaque hemorrhage, loose matrix, thrombosis, and ulcers, subject to resolution limitations of current technology [1]. Image-based computational models have also been developed which combine mechanical analysis with image technology aiming for more accurate assessment of plaque vulnerability and better diagnostic and treatment decisions [2]. However, 3D models with fluid-structure interactions (FSI), cyclic bending and anisotropic properties based on in vivo IVUS images for human coronary atherosclerotic plaques are lacking in the current literature. In this paper, we introduce 3D FSI models based on in vivo IVUS images to perform mechanical analysis for human coronary plaques. Cyclic bending is included to represent deformation caused by cardiac motion. An anisotropic material model was used for the vessel so that the models would be more realistic for more accurate computational flow and stress/strain predictions.

A Framework to Assess Human Coronary Plaque Vulnerability Using Intravascular Ultrasound, On-Site Pressure, Angiography, and Anisotropic FSI Models

2012 ◽  
Author(s):  
Haofei Liu ◽  
Mingchao Cai ◽  
Chun Yang ◽  
Jie Zheng ◽  
Richard Bach ◽  
...  
Keyword(s):  
Intravascular Ultrasound ◽  
Computational Models ◽  
Plaque Rupture ◽  
Coronary Plaque ◽  
Critical Flow ◽  
Stress Strain ◽  
Flow Measurements ◽  
Biaxial Mechanical Testing ◽  
Atherosclerotic Plaque Rupture

Atherosclerotic plaque rupture is believed to be associated with critical flow and stress/strain conditions. Image-based computational models have been developed to identify critical flow and stress/strain conditions in the plaque [1–3]. In vivo image-based coronary plaque modeling papers are relatively rare because clinical recognition of vulnerable coronary plaques has remained challenging [4]. In this paper, a framework adopting intravascular ultrasound (IVUS) imaging with on-site pressure and flow measurements, biaxial mechanical testing and computational modeling is proposed to construct 3D coronary plaque for more accurate stress/strain predictions.

scholarly journals Impact of Coronary Plaque Vulnerability on Acute Cardiovascular Events – Design of a CT-based 2-year Follow-up Study

2019 ◽  
Vol 4 (2) ◽  
pp. 64-71
Author(s):  
Noémi Mitra ◽  
Roxana Hodas ◽  
Evelin Szabó ◽  
Zsolt Parajkó ◽  
Theodora Benedek ◽  
...  
Keyword(s):  
Cardiovascular Events ◽  
Plaque Rupture ◽  
Coronary Plaque ◽  
Plaque Vulnerability ◽  
Mortality And Morbidity ◽  
Diagnostic Strategies ◽  
Major Cardiovascular Events ◽  
Artery Disease ◽  
Improve Patient

Abstract With coronary artery disease (CAD) projected to remain the leading cause of global mortality, prevention strategies seem to be the only effective approach able to reduce the burden and improve mortality and morbidity. At this moment, diagnostic strategies focus mainly on symptomatic patients, ignoring the occurrence of major cardiovascular events as the only manifestation of CAD. As two thirds of fatal myocardial infarction are resulting from plaque rupture, an approach based on the “vulnerable plaque” concept is mandatory in order to improve patient diagnosis, treatment, and, by default, prognosis. Given that the main studies focus on a plaque-centered approach, this is a prospective observational study that will perform a complex assessment of the features that characterize unstable coronary lesions, in terms of both local assessment via specific coronary computed tomography angiography markers of coronary plaque vulnerability and systemic approach based on serological markers of systemic inflammation in patients proved to be “vulnerable” by developing acute cardiovascular events.

scholarly journals Quantifying Effects of Plaque Structure and Material Properties on Stress Distributions in Human Atherosclerotic Plaques Using 3D FSI Models

2005 ◽  
Vol 127 (7) ◽  
pp. 1185-1194 ◽  
Author(s):  
Dalin Tang ◽  
Chun Yang ◽  
Jie Zheng ◽  
Pamela K. Woodard ◽  
Jeffrey E. Saffitz ◽  
...  
Keyword(s):  
Material Properties ◽  
Plaque Rupture ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Atherosclerotic Plaques ◽  
Plaque Vulnerability ◽  
Stress Strain ◽  
Maximal Stress ◽  
Good Potential ◽  
Stress Variations

Background: Atherosclerotic plaques may rupture without warning and cause acute cardiovascular syndromes such as heart attack and stroke. Methods to assess plaque vulnerability noninvasively and predict possible plaque rupture are urgently needed. Method: MRI-based three-dimensional unsteady models for human atherosclerotic plaques with multi-component plaque structure and fluid-structure interactions are introduced to perform mechanical analysis for human atherosclerotic plaques. Results: Stress variations on critical sites such as a thin cap in the plaque can be 300% higher than that at other normal sites. Large calcification block considerably changes stress/strain distributions. Stiffness variations of plaque components (50% reduction or 100% increase) may affect maximal stress values by 20–50 %. Plaque cap erosion causes almost no change on maximal stress level at the cap, but leads to 50% increase in maximal strain value. Conclusions: Effects caused by atherosclerotic plaque structure, cap thickness and erosion, material properties, and pulsating pressure conditions on stress/strain distributions in the plaque are quantified by extensive computational case studies and parameter evaluations. Computational mechanical analysis has good potential to improve accuracy of plaque vulnerability assessment.

scholarly journals New Insights into the Association between Fibrinogen and Coronary Atherosclerotic Plaque Vulnerability: An Intravascular Optical Coherence Tomography Study

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jun Wang ◽  
Lu Jia ◽  
Xing Li ◽  
Siyu Jin ◽  
Xiaomei Li ◽  
...  
Keyword(s):  
Coronary Heart Disease ◽  
Optical Coherence Tomography ◽  
Heart Disease ◽  
Plaque Rupture ◽  
Experimental Studies ◽  
High Body Mass Index ◽  
Coronary Plaque ◽  
Optical Coherence ◽  
Plaque Vulnerability ◽  
Coronary Syndrome

Background. Fibrinogen levels have been associated with coronary plaque vulnerability in experimental studies. However, it has yet to be determined if serum fibrinogen levels are independently associated with coronary plaque vulnerability as detected by optical coherence tomography (OCT) in patients with coronary heart disease. Methods. Patients with coronary heart disease (CHD) who underwent coronary angiography and OCT in our department from January 2015 to August 2018 were included in this study. Coronary lesions were categorized as ruptured plaque, nonruptured with thin-cap fibroatheroma (TCFA), and nonruptured and non-TCFA. Presence of ruptured plaque and nonruptured with TCFA was considered to be vulnerable lesions. Determinants of coronary vulnerability were evaluated by multivariable logistic regression analyses. Results. A total of 154 patients were included in this study; 17 patients had ruptured plaques, 15 had nonruptured plaques with TCFA, and 122 had nonruptured plaques with non-TCFA. Results of univariate analyses showed that being male, diabetes, current smoking, high body mass index (BMI), and clinical diagnosis of acute coronary syndrome (ACS) were associated with coronary vulnerability. No significant differences were detected in patient characteristics, coronary angiographic findings, and OCT results between patients with higher and normal fibrinogen. Results of multivariate logistic analyses showed that diabetes and ACS were associated with TCFA, while diabetes, higher BMI, and ACS were associated with plaque rupture. Conclusions. Diabetes, higher BMI, and ACS are independently associated with coronary vulnerability as detected by OCT. Serum fibrinogen was not associated with coronary vulnerability in our cohort.

scholarly journals Multi-patient study for coronary vulnerable plaque model comparisons: 2D/3D and fluid–structure interaction simulations

2021 ◽  
Author(s):  
Qingyu Wang ◽  
Dalin Tang ◽  
Liang Wang ◽  
Akiko Meahara ◽  
David Molony ◽  
...  
Keyword(s):  
Computational Models ◽  
Wall Stress ◽  
3D Models ◽  
Coronary Plaque ◽  
Maximum Pressure ◽  
Plaque Progression ◽  
Fluid Structure ◽  
Cyclic Bending ◽  
Model Comparisons

AbstractSeveral image-based computational models have been used to perform mechanical analysis for atherosclerotic plaque progression and vulnerability investigations. However, differences of computational predictions from those models have not been quantified at multi-patient level. In vivo intravascular ultrasound (IVUS) coronary plaque data were acquired from seven patients. Seven 2D/3D models with/without circumferential shrink, cyclic bending and fluid–structure interactions (FSI) were constructed for the seven patients to perform model comparisons and quantify impact of 2D simplification, circumferential shrink, FSI and cyclic bending plaque wall stress/strain (PWS/PWSn) and flow shear stress (FSS) calculations. PWS/PWSn and FSS averages from seven patients (388 slices for 2D and 3D thin-layer models) were used for comparison. Compared to 2D models with shrink process, 2D models without shrink process overestimated PWS by 17.26%. PWS change at location with greatest curvature change from 3D FSI models with/without cyclic bending varied from 15.07% to 49.52% for the seven patients (average = 30.13%). Mean Max-FSS, Min-FSS and Ave-FSS from the flow-only models under maximum pressure condition were 4.02%, 11.29% and 5.45% higher than those from full FSI models with cycle bending, respectively. Mean PWS and PWSn differences between FSI and structure-only models were only 4.38% and 1.78%. Model differences had noticeable patient variations. FSI and flow-only model differences were greater for minimum FSS predictions, notable since low FSS is known to be related to plaque progression. Structure-only models could provide PWS/PWSn calculations as good approximations to FSI models for simplicity and time savings in calculation.

scholarly journals Relationship between monocyte-to-lymphocyte ratio and coronary plaque vulnerability in patients with acute coronary syndrome: an optical coherence tomography study

2019 ◽  
Author(s):  
Ting-yu Zhang ◽  
Qi Zhao ◽  
Ze-sen Liu ◽  
Chao-yi Zhang ◽  
Jie Yang ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Acute Coronary Syndrome ◽  
Plaque Rupture ◽  
Coronary Plaque ◽  
Plaque Morphology ◽  
Multivariable Logistic Regression Analysis ◽  
Optical Coherence ◽  
Plaque Vulnerability ◽  
Lymphocyte Ratio ◽  
Coronary Syndrome

Abstract Background The importance of monocyte-to-lymphocyte ratio (MLR) has been indicated in the initiation and progression of coronary artery disease (CAD). However, few previous researches demonstrated the relationship between MLR and plaque vulnerability. We aimed to investigate coronary plaque vulnerability in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). Methods A total of 72 ACS patients who underwent coronary angiography and OCT test in Beijing Anzhen hospital were included in this retrospective study. The plaque vulnerability and plaque morphology were assessed by OCT. Results The coronary plaque in high MLR group exhibited more vulnerable features, characterizing as thinner thickness of fibrous cap (FCT)(112.37 ± 60.24 vs 153.49 ± 73.29 μm, P = 0.013), greater maximum lipid core angle (167.36 ± 62.33 vs 138.79 ± 56.37°, P = 0.010) and longer lipid plaque length (6.34 ± 3.12 vs 4.50 ± 2.21mm, P = 0.041). A prominently negative liner relation was found between MLR and FCT (R = 0.225, P < 0.005). Meanwhile, the incidence of OCT-detected thin cap fibro-atheroma (TCFA) (44.7% vs 18.4%, P = 0.014) and plaque rupture (36.8% vs 13.2%, P = 0.017) were higher in high MLR group. Most importantly, multivariable logistic regression analysis showed MLR level was related to the presence of TCFA (OR:3.316，95%：1.448-7.593，P = 0.005). MLR level could differentiate TCFA with a sensitivity of 72.0% and a specificity of 66.1%. Conclusion Circulating MLR level has potential value in identifying the presence of vulnerable plaque in patients with ACS. MLR, as a non- invasive biomarker of inflammation, may be valuable in revealing plaque vulnerability. Key words Monocyte-to-lymphocyte ratio, Optical coherence tomography, Plaque vulnerability

Determination of Human Carotid Atherosclerotic Plaque Material Properties Non-Invasively Using In Vivo Cine and 3D Magnetic Resonance Imaging and Image-Based Modeling Techniques

2011 ◽  
Author(s):  
Haofei Liu ◽  
Gador Canton ◽  
Chun Yuan ◽  
Marina Ferguson ◽  
Chun Yang ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Atherosclerotic Plaque ◽  
Material Properties ◽  
Computational Models ◽  
Plaque Rupture ◽  
Patient Specific ◽  
Material Strength ◽  
Modeling Techniques ◽  
Human Carotid

Atherosclerotic plaque rupture is believed to be associated with high critical stress exceeding plaque cap material strength. In vivo magnetic resonance image (MRI)-based computational models have been introduced to calculate critical plaque stress and assess plaque vulnerability [1–5]. However, accuracy of computational stress predictions is heavily dependent on the data used by the models. Patient-specific plaque material properties are desirable for accurate stress predictions but are not currently available. In this paper, non-invasive in vivo Cine and 3D multicontrast MRI data and modeling techniques were combined to obtain patient-specific plaque material properties to improve model prediction accuracies. A 2D human carotid plaque model was used to demonstrate impact of material stiffness on computational stress predictions.

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