Estimation of patient-specific material properties of the mitral valve using 4D Transesophageal Echocardiography

4D Transesophageal Echocardiography (TEE) is a newly developed tool to visualize the morphology and dynamics of the mitral valve for diagnosis and treatment planning. Quantitative patient-specific modeling of the mitral valve is demanded since it allows for the reliable predictive simulation of medical intervention. State-of-the-art image-based and biomechanical models with generic material parameters have limited predictive power as they are only partially fitted to patient-data. As a step closer to a fully personalized model, an estimation algorithm is presented in this paper. The method combines image-derived mitral valve dynamics with a biomechanical model to estimate regional patient-specific material parameters in-vivo. In particular, the extended Kalman filter (EKF) is adopted in a way that it becomes flexible to integrate any biomechanical model and more parameters of interest in the estimation. The algorithm was verified on synthetic data with known Young´s modulus and shear modulus, yielding less than 5% error. The algorithm was also evaluated on 4D TEE images of five patients. Estimated Young´s moduli agree with the clinical observation that material parameters vary regionally and among the population. The estimated material parameters can be used in patient-specific modeling as well as the detection and evaluation of diseased areas.