Mitral Valve Patient-Specific Finite Element Modeling from Cardiac MRI: Application to an Annuloplasty Procedure

摘要

We aim at testing the possibility to build patient-specific structural finite element models (FEMs) of the mitral valve (MV) from cardiac magnetic resonance (CMR) imaging and to use them to predict the outcome of mitral annuloplasty procedures. MV FEMs were built for one healthy subject and for one patient with ischemic mitral regurgitation. On both subjects, CMR imaging of 18 long-axis planes was performed with a temporal resolution of 55 time-frames per cardiac cycle. Three-dimensional MV annu-lus geometry, leaflets surface and PM position were manually obtained using custom software. Hyperelastic anisotropic mechanical properties were assigned to MV tissues. A physiological pressure load was applied to the leaflets to simulate valve closure until peak systole. For the pathological model only, a further simulation was run, simulating undersized rigid annuloplasty before valve closure. Closure dynamics, leaflets stresses and tensions in the subvalvular apparatus in the healthy MV were consistent with previous computational and experimental data. The regurgitant valve model captured with good approximation the real size and position of regurgitant areas at peak systole, and highlighted abnormal tensions in the annular region and sub-valvular apparatus. The simulation of undersized rigid annuloplasty showed the restoration of MV continence and normal tensions in the subvalvular apparatus and at the annulus. Our method seems suitable for implementing detailed patient-specific MV FEMs to simulate different scenarios of clinical interest. Further work is mandatory to test the method more deeply, to reduce its computational time and to expand the range of modeled surgical procedures.