We propose a surrogate model for the fluid-structure interaction (FSI) problem for the study of blood dynamics in carotid arteries in presence of plaque. This is based on the integration of a numerical model with subject-specific data and clinical imaging. We propose to model the plaque as part of the tissues surrounding the vessel wall through the application of an elastic support boundary condition. In order to characterize the plaque and other surrounding tissues, such as the close-by jugular vein, the elastic parameters of the boundary condition were spatially differentiated and their values were estimated by minimizing the discrepancies between computed vessel displacements and reference values obtained from CINE Magnetic Resonance Imaging data. We applied the model to three subjects with a degree of stenosis greater than 70%. We found that accounting for both plaque and jugular vein in the estimation of the elastic parameters increases the accuracy. In particular, in all patients, mismatches between computed and in vivo measured wall displacements were one to two orders of magnitude lower than the spatial resolution of the original MRI data. These results confirmed the validity of the proposed surrogate plaque model. We also compared fluid-dynamics results with those obtained in a fixed wall setting and in a full FSI model, used as gold standard, highlighting the better accordance of our results in comparison to the rigid ones.
#1Chengzhen Xu(Huaibei Normal University)H-Index: 1
#2Longjian Gao(Huaibei Normal University)H-Index: 1
Last. Xiaomin Wu(Huaibei Normal University)H-Index: 1
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RNA functions, including the regulation of various cellular activities, seem to be closely related to its structure. However, accurately predicting RNA secondary structures can be difficult. Struct...
Re : "Management of Atherosclerotic Carotid and Vertebral Disease: 2017 Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS)"
Background Closure technique after carotid endarterectomy (CEA) still remains an issue of debate. Routine use of patch graft (PG) has been advocated to reduce restenosis, stroke, and death, but its protective effect, particularly from late restenosis, is less evident and recent studies call into question this thesis. This study aims to compare PG and direct suture (DS) by means of computational fluid dynamics (CFD). To identify carotid regions with flow recirculation more prone to restenosis dev...
#2Gador Canton(UW: University of Washington)H-Index: 19
Last. Dalin Tang(SEU: Southeast University)H-Index: 30
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BACKGROUND: Image-based computational models are widely used to determine atherosclerotic plaque stress/strain conditions and investigate their association with plaque progression and rupture. However, patient-specific vessel material properties are in general lacking in those models, limiting the accuracy of their stress/strain measurements. A noninvasive approach of combining in vivo 3D multi-contrast and Cine magnetic resonance imaging (MRI) and computational modeling was introduced to quanti...
Mathematical and numerical modelling of the cardiovascular system is a research topic that has attracted remarkable interest from the mathematical community because of its intrinsic mathematical difficulty and the increasing impact of cardiovascular diseases worldwide. In this review article we will address the two principal components of the cardiovascular system: arterial circulation and heart function. We will systematically describe all aspects of the problem, ranging from data imaging acqui...
#1Simone Deparis(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 20
#2Davide Forti(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 10
Last. Alfio Quarteroni(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 83
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Modeling Fluid-Structure Interaction (FSI) in the vascular system is mandatory to reliably compute mechanical indicators in vessels undergoing large deformations. In order to cope with the computational complexity of the coupled 3D FSI problem after discretizations in space and time, a parallel solution is often mandatory. In this paper we propose a new block parallel preconditioner for the coupled linearized FSI system obtained after space and time discretization. We name it FaCSI to indicate t...
Last. Christian Vergara(IPN: Instituto Politécnico Nacional)H-Index: 24
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This review paper addresses the so called geometric multiscale approach for the numerical simulation of blood flow problems, from its origin (that we can collocate in the second half of '90s) to our days. By this approach the blood fluid-dynamics in the whole circulatory system is described mathematically by means of heterogeneous problems featuring different degree of detail and different geometric dimension that interact together through appropriate interface coupling conditions. Our review st...
In this work, we provide a computational study of the effects of carotid endarterectomy (CEA) on the fluid-dynamics at internal carotid bifurcations. We perform numerical simulations in real geometries of the same patients before and after CEA, using patient-specific boundary data obtained by Echo-Color Doppler measurements. We analyze four patients with a primary closure and other four where a patch was used to close arteriotomies. The results show that (i) CEA is able to restore physiological ...
Carotid artery stenosis is a well-established risk factor of ischemic stroke, contributing to up to 10%-20% of strokes or transient ischemic attacks. Many clinical trials over the last 20 years have used measurements of carotid artery stenosis as a means to risk stratify patients. However, with improvements in vascular imaging techniques such as CT angiography and MR angiography, ultrasonography, and PET/CT, it is now possible to risk stratify patients, not just on the degree of carotid artery s...
Atherosclerosis is a systemic disease that leads to accumulation of deposits, known as atherosclerotic plaques, within the walls of the carotids. In particular, three types of plaque can be distinguished: soft, fibrous and calcific. Most of the computational studies who investigated the interplay between the plaque and the blood flow on patient-specific geometries, used non standard medical images to directly delineate and segment the plaque and its components. However these techniques are not s...