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.

Sudden Death in Coronary Artery Disease are Associated With High 3D Critical Plaque Wall Stress: A 3D Multi-Patient FSI Study Based on Ex Vivo MRI of Coronary Plaques

2013 ◽  
Author(s):  
Xueying Huang ◽  
Chun Yang ◽  
Jie Zheng ◽  
Richard Bach ◽  
David Muccigrosso ◽  
...  
Keyword(s):  
Computational Models ◽  
Plaque Rupture ◽  
Ex Vivo ◽  
Carotid Artery Disease ◽  
Wall Stress ◽  
Carotid Plaques ◽  
Group 2 ◽  
Artery Disease ◽  
Atherosclerotic Plaque Rupture

Atherosclerotic plaque rupture is the primary cause of cardiovascular clinical events such as heart attack and stroke. It is commonly believed that plaque rupture may be linked to critical mechanical conditions. Image-based computational models of vulnerable plaques have been introduced seeking critical mechanical indicators which may be used to identify potential sites of rupture [1–5]. A recent study by Tang et al. [4] using in vivo MRI-based 3D fluid-structure interaction (FSI) models for human carotid plaques with and without rupture reported that higher critical plaque wall stress (CPWS) values were associated with plaques with rupture, compared to those without rupture. However, existing computational plaque models are mostly for carotid plaques based on MRI data. Comparable similar studies for coronary plaques are lacking in the current literature. In this study, 3D computational multi-component models with FSI were constructed to identified 3D critical plaque wall stress, critical flow shear stress (CFSS) based on ex vivo MRI data of coronary plaques acquired from 10 patients. The patients were split into 2 groups: patients died in carotid artery disease (CAD, Group 1, 6 patients) and non CAD (Group 2, 4 patients). The possible link between CPWS and death in CAD was investigated by comparing the CPWS values from the two groups.

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.

Abstract 383: Patient-Specific Coronary Models Combining Intravascular Ultrasound and Optical Coherence Tomography Lead to More Accurate Plaque Cap Thickness and Stress/Strain Quantifications

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Xiaoya Guo ◽  
David Monoly ◽  
Chun Yang ◽  
Habib Samady ◽  
Jie Zheng ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Intravascular Ultrasound ◽  
Coronary Plaque ◽  
Patient Specific ◽  
Data Sets ◽  
Optical Coherence ◽  
Stress Strain ◽  
Data Set ◽  
The Impact

Accurate cap thickness and stress/strain quantifications are of fundamental importance for vulnerable plaque research. An innovative modeling approach combining intravascular ultrasound (IVUS) and optical coherence tomography (OCT) is introduced for more accurate patient-specific coronary morphology and stress/strain calculations. In vivo IVUS and OCT coronary plaque data were acquired from two patients with informed consent obtained. IVUS and OCT images were segmented, co-registered, and merged to form the IVUS+OCT data set, with OCT providing accurate cap thickness. Biplane angiography provided 3D vessel curvature. Due to IVUS resolution (150 μm), original virtual histology (VH) IVUS data often had lipid core exposed to lumen since it sets cap thickness as zero when cap thickness <150 μm. VH-IVUS data were processed with minimum cap thickness set as 50 and 180 μm to generate IVUS50 and IVUS180 data sets for modeling use. 3D fluid-structure interaction models based on IVUS+OCT, IVUS50 and IVUS180 data sets were constructed to investigate the impact of OCT cap thickness improvement on stress/strain calculations. Figure 1 is a brief summary of results from 27 slices with cap covering lipid cores from 2 patients. Mean cap thickness (unit: mm) from Patient 1 was 0.353 (OCT), 0.201 (IVUS50), and 0.329 (IVUS180), respectively. Patient 2 mean cap thickness was 0.320 (OCT), 0.224 (IVUS50), and 0.285 (IVUS180). IVUS50 underestimated cap thickness (27 slices) by 34.5%, compared to OCT cap values. IVUS50 overestimated mean cap stress (27 slices) by 45.8%, compared to OCT cap stress (96.4 vs. 66.1 kPa). IVUS50 maximum cap stress was 59.2% higher than that from IVUS+OCT model (564.2 vs. 354.5 kPa). Differences between IVUS and IVUS+OCT models for mean cap strain and flow shear stress were modest (cap strain: <12%; FSS <2%). Conclusion: IVUS+OCT data and models could provide more accurate cap thickness and stress/strain calculations which will serve as basis for plaque research.

Strain Measurement in Coronary Arteries Using Intravascular Ultrasound and Deformable Images

2002 ◽  
Vol 124 (6) ◽  
pp. 734-741 ◽  
Author(s):  
Alexander I. Veress ◽  
Jeffrey A. Weiss ◽  
Grant T. Gullberg ◽  
D. Geoffrey Vince ◽  
Richard D. Rabbitt
Keyword(s):  
Finite Element ◽  
Intravascular Ultrasound ◽  
Coronary Arteries ◽  
Strain Distribution ◽  
Plaque Rupture ◽  
Element Model ◽  
Cross Sectional ◽  
Image Pairs

Atherosclerotic plaque rupture is responsible for the majority of myocardial infarctions and acute coronary syndromes. Rupture is initiated by mechanical failure of the plaque cap, and thus study of the deformation of the plaque in the artery can elucidate the events that lead to myocardial infarction. Intravascular ultrasound (IVUS) provides high resolution in vitro and in vivo cross-sectional images of blood vessels. To extract the deformation field from sequences of IVUS images, a registration process must be performed to correlate material points between image pairs. The objective of this study was to determine the efficacy of an image registration technique termed Warping to determine strains in plaques and coronary arteries from paired IVUS images representing two different states of deformation. The Warping technique uses pointwise differences in pixel intensities between image pairs to generate a distributed body force that acts to deform a finite element model. The strain distribution estimated by image-based Warping showed excellent agreement with a known forward finite element solution, representing the gold standard, from which the displaced image was created. The Warping technique had a low sensitivity to changes in material parameters or material model and had a low dependency on the noise present in the images. The Warping analysis was also able to produce accurate strain distributions when the constitutive model used for the Warping analysis and the forward analysis was different. The results of this study demonstrate that Warping in conjunction with in vivo IVUS imaging will determine the change in the strain distribution resulting from physiological loading and may be useful as a diagnostic tool for predicting the likelihood of plaque rupture through the determination of the relative stiffness of the plaque constituents.

scholarly journals Distance from the ostium as an independent determinant of coronary plaque composition in vivo: an intravascular ultrasound study based radiofrequency data analysis in humans

2006 ◽  
Vol 27 (6) ◽  
pp. 655-663 ◽  
Author(s):  
Marco Valgimigli ◽  
Gastón A. Rodriguez-Granillo ◽  
Héctor M. Garcia-Garcia ◽  
Patrizia Malagutti ◽  
Evelyn Regar ◽  
...  
Keyword(s):  
Data Analysis ◽  
Intravascular Ultrasound ◽  
Coronary Plaque ◽  
Plaque Composition ◽  
Ultrasound Study ◽  
Independent Determinant

INTRAVASCULAR ULTRASOUND PALPOGRAPHY: A NEW METHOD FOR THE DETECTION OF THE VULNERABLE PLAQUE

2006 ◽  
Vol 06 (01) ◽  
pp. 35-38
Author(s):  
FRANCESCO SAIA ◽  
JOHANNES A. SCHAAR ◽  
FRITS MASTIK ◽  
CHRIS L. DE KORTE ◽  
SAMANTHA CORNACCHIA ◽  
...  
Keyword(s):  
Intravascular Ultrasound ◽  
Plaque Rupture ◽  
Coronary Thrombosis ◽  
Local Strain ◽  
Coronary Event ◽  
Diagnostic Methods ◽  
Atherosclerotic Plaques ◽  
Clinical Markers ◽  
Coronary Syndromes ◽  
Atherosclerotic Plaque Rupture

Acute coronary syndromes originate from atherosclerotic plaque rupture and subsequent developement of coronary thrombosis. Available screening and diagnostic methods are insufficient to identify the atherosclerotic plaques that will rupture and precipitate the coronary event. We developed a new intracoronary diagnostic method based on intravascular ultrasound (IVUS) examination to evaluate the local mechanical properties of atherosclerotic plaques namely IVUS-elastography/palpography. The relationships between local strain, histological features of vulnerability, clinical presentation, and clinical markers of instability were assessed.

scholarly journals 3D Critical Plaque Wall Stress Is a Better Predictor of Carotid Plaque Rupture Sites Than Flow Shear Stress: An In Vivo MRI-Based 3D FSI Study

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Zhongzhao Teng ◽  
Gador Canton ◽  
Chun Yuan ◽  
Marina Ferguson ◽  
Chun Yang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Plaque Rupture ◽  
Wall Stress ◽  
Flow Shear ◽  
Flow Shear Stress ◽  
The Mean ◽  
Group 2 ◽  
Atherosclerotic Plaque Rupture ◽  
Group 1

Atherosclerotic plaque rupture leading to stroke is the major cause of long-term disability as well as the third most common cause of mortality. Image-based computational models have been introduced seeking critical mechanical indicators, which may be used for plaque vulnerability assessment. This study extends the previous 2D critical stress concept to 3D by using in vivo magnetic resonance image (MRI) data of human atherosclerotic carotid plaques and 3D fluid-structure interaction (FSI) models to: identify 3D critical plaque wall stress (CPWS) and critical flow shear stress (CFSS) and to investigate their associations with plaque rupture. In vivo MRI data of carotid plaques from 18 patients scheduled for endarterectomy were acquired using histologically validated multicontrast protocols. Of the 18 plaques, histology-confirmed that six had prior rupture (group 1) as evidenced by presence of ulceration. The remaining 12 plaques (group 2) contained no rupture. The 3D multicomponent FSI models were constructed for each plaque to obtain 3D plaque wall stress (PWS) and flow shear stress (FSS) distributions. Three-dimensional CPWS and CFSS, defined as maxima of PWS and FSS from all vulnerable sites, were determined for each plaque to investigate their association with plaque rupture. Slice-based critical PWS and FSS were also calculated for all slices for more detailed analysis and comparison. The mean 3D CPWS of group 1 was 263.44 kPa, which was 100% higher than that from group 2 (132.77, p=0.03984). Five of the six ruptured plaques had 3D CPWS sites, matching the histology-confirmed rupture sites with an 83% agreement. Although the mean 3D CFSS (92.94 dyn/cm2) for group 1 was 76% higher than that for group 2 (52.70 dyn/cm2), slice-based CFSS showed no significant difference between the two groups. Only two of the six ruptured plaques had 3D CFSS sites matching the histology-confirmed rupture sites with a 33% agreement. CFSS had a good correlation with plaque stenosis severity (R2=0.40 with an exponential function fitting 3D CFSS data). This in vivo MRI pilot study using plaques with and without rupture demonstrates that 3D critical plaque wall stress values are more closely associated with atherosclerotic plaque rupture then critical flow shear stresses. Critical wall stress values may become indicators of high risk sites of rupture. Future work with a larger population will establish a possible CPWS-based plaque vulnerability classification.

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