1. A method of mitral valve segmentation from a plurality of 2D cardiac magnetic resonance (CMR) slices, comprising: detecting a set of mitral valve landmarks in each of the 2D CMR slices; estimating mitral valve contours in each of the 2D CMR slices based on the detected landmarks; and reconstructing a 3D mitral valve model from the mitral valve contours in the 2D CMR slices using a trained regression model.