Human Carotid Atherosclerotic Plaque Growth Function and Progression Simulation Using Meshless GFD and Statistical Methods Based on Multi-Year In Vivo MRI

Author(s):  
Chun Yang ◽  
Joseph D. Petruccelli ◽  
Zhongzhao Teng ◽  
Chun Yuan ◽  
Gador Canton ◽  
...  

Atherosclerotic plaque rupture and progression have been the focus of intensive investigations in recent years. The mechanisms governing plaque progression and rupture process are not well understood. Using computational models based on patient-specific multi-year in vivo MRI data, our recent results indicated that 18 out of 21 patients studied showed significant negative correlation between plaque progression measured by vessel wall thickness increase (WTI) and plaque wall (structural) stress (PWS) [1]. In this paper, a computational procedure based on meshless generalized finite difference (MGFD) method and serial magnetic resonance imaging (MRI) data was introduced to simulate plaque progression. Participating patients were scanned three times (T1, T2, and T3, at intervals of approximately 18 months) to obtain plaque progression data. Vessel wall thickness (WT) changes were used as the measure for plaque progression. Starting from T2 plaque geometry, plaque progression was simulated by solving the solid model and adjusting wall thickness using plaque growth functions iteratively until time T3 is reached. Numerically simulated plaque progression showed very good agreement with actual plaque geometry at T3 given by MRI data. We believe this is the first time plaque progression simulation results based on multi-year patient-tracking data are reported. Multi-year tracking data and MRI-based progression simulation add time dimension to plaque vulnerability assessment and will improve prediction accuracy.

Author(s):  
Chun Yang ◽  
Gador Canton ◽  
Chun Yuan ◽  
Tom Hatsukami ◽  
Dalin Tang

Atherosclerotic plaque progression involves biological, structural and mechanical factors. Previous work has shown that initiation and early progression of atherosclerotic plaque correlate negatively with flow wall shear stresses [1–2]. However, plaque growth functions based on patient-specific data to predict future plaque growth are lacking in the current literature. Six plaque growth functions based on fluid-structure-interaction (FSI) models and in vivo serial magnetic resonance image (MRI) data were proposed for progression prediction. This is to test the hypothesis that combining plaque morphology, plaque wall maximum principal stress (WS), strain (WSN) and flow maximum shear stress (FSS) could better predict plaque progression.


Author(s):  
Hao Gao ◽  
Quan Long ◽  
Martin Graves ◽  
Jonathan H. Gillard ◽  
Zhi-Yong Li

Rupture of atherosclerotic plaque is a major cause of mortality. Plaque stress analysis, based on patient-specific multi-sequence in vivo magnetic resonance images (MRI), can provide critical information for the understanding of plaque rupture and could eventually lead to plaque rupture prediction [1].


Author(s):  
Haofei Liu ◽  
Gador Canton ◽  
Chun Yuan ◽  
Marina Ferguson ◽  
Chun Yang ◽  
...  

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.


Author(s):  
Annika Niemann ◽  
Samuel Voß ◽  
Riikka Tulamo ◽  
Simon Weigand ◽  
Bernhard Preim ◽  
...  

Abstract Purpose For the evaluation and rupture risk assessment of intracranial aneurysms, clinical, morphological and hemodynamic parameters are analyzed. The reliability of intracranial hemodynamic simulations strongly depends on the underlying models. Due to the missing information about the intracranial vessel wall, the patient-specific wall thickness is often neglected as well as the specific physiological and pathological properties of the vessel wall. Methods In this work, we present a model for structural simulations with patient-specific wall thickness including different tissue types based on postmortem histologic image data. Images of histologic 2D slices from intracranial aneurysms were manually segmented in nine tissue classes. After virtual inflation, they were combined into 3D models. This approach yields multiple 3D models of the inner and outer wall and different tissue parts as a prerequisite for subsequent simulations. Result We presented a pipeline to generate 3D models of aneurysms with respect to the different tissue textures occurring in the wall. First experiments show that including the variance of the tissue in the structural simulation affect the simulation result. Especially at the interfaces between neighboring tissue classes, the larger influence of stiffer components on the stability equilibrium became obvious. Conclusion The presented approach enables the creation of a geometric model with differentiated wall tissue. This information can be used for different applications, like hemodynamic simulations, to increase the modeling accuracy.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
E M J Hartman ◽  
A M Kok ◽  
A Hoogendoorn ◽  
F J H Gijsen ◽  
A F W Steen ◽  
...  

Abstract Introduction Local wall shear stress (WSS) metrics, high local lipid levels (as detected by near-infrared spectroscopy (NIRS)), as well as systemic lipid levels, have been individually associated with atherosclerotic disease progression. However, a possible synergistic effect remains to be elucidated. This study is the first study to combine WSS metrics with NIRS-detected local lipid content to investigate a potential synergistic effect on plaque progression in human coronary arteries. Methods The IMPACT study is a prospective, single centre study investigating the relation between atherosclerotic plaque progression and WSS in human coronary arteries. Patients with ACS treated with PCI were included. At baseline and after 1-year follow-up, patients underwent near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) imaging and intravascular doppler flow measurements of at least one non-culprit coronary artery. After one month, a CT angiography was made. CT derived centreline combined with IVUS lumen contours resulted in a 3D reconstruction of the vessel. The following WSS metrics were computed using computational fluid dynamics applying the vessel specific invasive flow measurements: time-average wall shear stress (TAWSS), relative residence time (RRT), cross-flow index, oscillatory shear index and transverse wall shear stress. Low TAWSS is known as pro atherogenic, in contrast to all the other shear stress metrics, at which a high magnitude is pro-atherogenic. The arteries were divided into 1.5mm/45° sectors. Based on NIRS-IVUS, wall thickness change over time was determined and NIRS positive sectors detected. Furthermore, per vessel the shear stress was divided into tertiles (low, intermediate, high). To investigate the synergistic effect of local lipids on shear stress related plaque growth, wall thickness change over time was related to the different shear stress metrics comparing the NIRS-positive with the NIRS-negative sectors. Results 15 non-culprit coronary arteries from the first 14 patients were analyzed (age 62±10 years old and 92.9% male). A total of 2219 sectors were studied (5.2%, N=130, NIRS-positive) for wall thickness changes. After studying all five shear stress metrics, we found for TAWSS and RRT that presence of lipids, as detected by NIRS, amplified the effect of shear stress on plaque progression (see figure). Sectors presenting with lipid-rich plaque, compared to NIRS-negative sectors, showed more progression when they were exposed to low TAWSS (p=0.07) or high RRT (p=0.012) and more regression in sectors exposed to high TAWSS (p=0.10) or low RRT (p=0.06). Delta wall thickness vs shear stress Conclusion We presented the first preliminary results of the IMPACT study, showing the synergistic effect of lipid rich plaque and shear stress on plaque progression. Therefore, intravascular lipid-rich plaque (NIRS) assessment has added value to shear stress profiling for the prediction of plaque growth, leading to improved risk stratification. Acknowledgement/Funding ERC starting grant 310457


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Qingyu Wang ◽  
Dalin Tang ◽  
Gador Canton ◽  
Jian Guo ◽  
Xiaoya Guo ◽  
...  

It is hypothesized that artery stiffness may be associated with plaque progression. However, in vivo vessel material stiffness follow-up data is lacking in the literature. In vivo 3D multi-contrast and Cine magnetic resonance imaging (MRI) carotid plaque data were acquired from 8 patients with follow-up (18 months) with written informed consent obtained. Cine MRI and 3D thin-layer models were used to determine parameter values of the Mooney-Rivlin models for the 81slices from 16 plaques (2 scans/patient) using our established iterative procedures. Effective Young’s Modulus (YM) values for stretch ratio [1.0,1.3] were calculated for each slice for analysis. Stress-stretch ratio curves from Mooney-Rivlin models for the 16 plaques and 81 slices are given in Fig. 1. Average YM value of the 81 slices was 411kPa. Slice YM values varied from 70 kPa (softest) to 1284 kPa (stiffest), a 1734% difference. Average slice YM values by vessel varied from 109 kPa (softest) to 922 kPa (stiffest), a 746% difference. Location-wise, the maximum slice YM variation rate within a vessel was 306% (139 kPa vs. 564 kPa). Average slice YM variation rate within a vessel for the 16 vessels was 134%. Average variation of YM values from baseline (T1) to follow up (T2) for all patients was 61.0%. The range of the variation of YM values was [-28.4%, 215%]. For progression study, YM increase (YMI=YM T2 -TM T1 ) showed negative correlation with plaque progression measured by wall thickness increase (WTI), (r= -0.6802, p=0.0634). YM T2 showed strong negative correlation with WTI (r= -0.7764, p=0.0235). Correlation between YM T1 and WTI was not significant (r= -0.4353, p= 0.2811). Conclusion In vivo carotid vessel material properties have large variations from patient to patient, along the vessel segment within a patient, and from baseline to follow up. Use of patient-specific, location specific and time-specific material properties could potentially improve the accuracy of model stress/strain calculations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David Schumacher ◽  
Elisa A. Liehn ◽  
Pakhwan Nilcham ◽  
David Castaño Mayan ◽  
Chutima Rattanasopa ◽  
...  

AbstractVascular restenosis remains a major problem in patients with coronary artery disease (CAD) and peripheral artery disease (PAD). Neointimal hyperplasia, defined by post-procedure proliferation and migration of vascular smooth muscle cells (VSMCs) is a key underlying pathology. Here we investigated the role of Interleukin 11 (IL-11) in a mouse model of injury-related plaque development. Apoe−/− mice were fed a hyperlipidaemic diet and subjected to carotid wire injury of the right carotid. Mice were injected with an anti-IL11 antibody (X203), IgG control antibody or buffer. We performed ultrasound analysis to assess vessel wall thickness and blood velocity. Using histology and immunofluorescence approaches, we determined the effects of IL-11 inhibition on VSMC and macrophages phenotypes and fibrosis. Treatment of mice with carotid wire injury using X203 significantly reduced post-endothelial injury vessel wall thickness, and injury-related plaque, when compared to control. Immunofluorescence staining of the injury-related plaque showed that X203 treatment did not reduce macrophage numbers, but reduced the number of VSMCs and lowered matrix metalloproteinase 2 (MMP2) levels and collagen content in comparison to control. X203 treatment was associated with a significant increase in smooth muscle protein 22α (SM22α) positive cells in injury-related plaque compared to control, suggesting preservation of the contractile VSMC phenotype. Interestingly, X203 also reduced the collagen content of uninjured carotid arteries as compared to IgG, showing an additional effect on hyperlipidemia-induced arterial remodeling in the absence of mechanical injury. Therapeutic inhibition of IL-11 reduced vessel wall thickness, attenuated neointimal hyperplasia, and has favorable effects on vascular remodeling following wire-induced endothelial injury. This suggests IL-11 inhibition as a potential novel therapeutic approach to reduce arterial stenosis following revascularization in CAD and PAD patients.


2013 ◽  
Vol 24 ◽  
pp. e38-e39
Author(s):  
Harrie CM van den Bosch ◽  
Jos JM Westenberg ◽  
Wikke Setz-Pels ◽  
Alette Daniels-Gooszen ◽  
Lucien EM Duijm ◽  
...  

Author(s):  
Nathalie Bijnens ◽  
Bart Beulen ◽  
Peter Brands ◽  
Marcel Rutten ◽  
Frans van de Vosse

In clinical practice, ultrasound is frequently applied to non-invasively assess blood velocity, blood volume flow and blood vessel wall properties such as vessel wall thickness and vessel diameter waveforms. To convert these properties into relevant biomechanical properties that are related to cardiovascular disease (CVD), such as elastic modulus and compliance of the vessel wall, local pressure has to be assessed simultaneously with vessel wall thickness and vessel diameter waveforms. Additionally, accurate estimates of vascular impedance (transfer function between pressure and blood flow) can be a valuable tool for the estimation of the condition of the vessel, e.g., to diagnose stenosis. Studies of arterial impedance in humans, however, are hampered by the lack of reliable non-invasive techniques to simultaneously record pressure and flow locally as a function of time. Local pressure assessment together with flow has great potential for improving the ability to diagnose and monitor CVD.


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