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.