%0 Journal Article %T A direct vulnerable atherosclerotic plaque elasticity reconstruction method based on an original material-finite element formulation: theoretical framework. %+ Dynamiques Cellulaire, Tissulaire & Microscopie fonctionnelle (TIMC-IMAG-DyCTiM) %+ Department of Electrical and Computer Engineering %+ Department of Mechanical Engineering %+ Department of Hemodynamics and Interventional Cardiology %+ Laboratoire de Mécanique et Génie Civil (LMGC) %+ Couplages en Géomécanique et Biomécanique (CGB) %+ Laboratory of Biorheology and Medical Ultrasonics (LBUM) %+ Laboratory of Integrative Cardiovascular Imaging Science %+ Polytech Annecy-Chambéry (EPU [Ecole Polytechnique Universitaire de l'Université de Savoie]) %A Bouvier, Adeline %A Deleaval, Flavien %A Doyley, Marvin M. %A Yazdani, Saami K. %A Finet, Gérard %A Le Floc'H, Simon %A Cloutier, Guy %A Pettigrew, Roderic I. %A Ohayon, Jacques %< avec comité de lecture %@ 0031-9155 %J Physics in Medicine and Biology %I IOP Publishing %V 58 %N 23 %P 8457-8476 %8 2013 %D 2013 %R 10.1088/0031-9155/58/23/8457 %M 24240392 %Z Computer Science [cs]/Modeling and Simulation %Z Life Sciences [q-bio]Journal articles %X The peak cap stress (PCS) amplitude is recognized as a biomechanical predictor of vulnerable plaque (VP) rupture. However, quantifying PCS in vivo remains a challenge since the stress depends on the plaque mechanical properties. In response, an iterative material finite element (FE) elasticity reconstruction method using strain measurements has been implemented for the solution of these inverse problems. Although this approach could resolve the mechanical characterization of VPs, it suffers from major limitations since (i) it is not adapted to characterize VPs exhibiting high material discontinuities between inclusions, and (ii) does not permit real time elasticity reconstruction for clinical use. The present theoretical study was therefore designed to develop a direct material-FE algorithm for elasticity reconstruction problems which accounts for material heterogeneities. We originally modified and adapted the extended FE method (Xfem), used mainly in crack analysis, to model material heterogeneities. This new algorithm was successfully applied to six coronary lesions of patients imaged in vivo with intravascular ultrasound. The results demonstrated that the mean relative absolute errors of the reconstructed Young's moduli obtained for the arterial wall, fibrosis, necrotic core, and calcified regions of the VPs decreased from 95.3 ± 15.56%, 98.85 ± 72.42%, 103.29 ± 111.86% and 95.3 ± 10.49%, respectively, to values smaller than 2.6 × 10(-8) ± 5.7 × 10(-8)% (i.e. close to the exact solutions) when including modified-Xfem method into our direct elasticity reconstruction method. %G English %2 https://hal.science/hal-01017137/document %2 https://hal.science/hal-01017137/file/LeFloch_al_Direct_vulnerable_atherosclerotic_plaque_Phys.Med.Biol._2013.pdf %L hal-01017137 %U https://hal.science/hal-01017137 %~ INSERM %~ UNIV-SAVOIE %~ UGA %~ IMAG %~ CNRS %~ UNIV-GRENOBLE1 %~ INPG %~ LMGC %~ TIMC-IMAG %~ TIMC-IMAG-DYCTIM %~ TDS-MACS %~ MIPS %~ UNIV-MONTPELLIER %~ UNIV-LYON %~ USMB-COMUE %~ UM-2015-2021