BAYESIAN-ESTIMATION OF VENTRICULAR CONTOURS IN ANGIOGRAPHIC IMAGES

This paper presents a new method for left ventricular contour determination in digital angiographic images. The problem is formulated in a Bayesian framework, adopting as estimation criterion the maximum a posteriori probability (MAP). The true contour is modeled as a one-dimensional noncausal Gauss-Markov random field and the observed image is described as the superposition of an ideal image (deterministic function of the real contour) with white Gaussian noise. The proposed algorithm estimates simultaneously the contour and the model parameters by implementing an adaptive version of the iterated conditional modes algorithm (AICM). The convergence of this scheme is proved and its performance evaluated on both synthetic and real angiographic images. The method exhibits robustness against image artifacts and the contours obtained are considered good by expert clinicians. Being completely data-driven and fast, the proposed algorithm is suitable for routine clinical use.