Active cardiac model and its application on structure detection from early fetal ultrasound sequences

The structure of an early fetal heart provides vital information for the diagnosis of fetus defects. However, early fetal hearts are difficult to detect due to their relatively small size and the low signal-to-noise ratio of ultrasound images. In this paper, a novel method is proposed for automatic detection of early fetal cardiac structure from ultrasound images. The proposed method consists of two major parts which are the preprocessing phase and the active cardiac model: (1) The preprocessing phase consists of two sub-steps. (a) The region of interest is first automatically selected based on an accumulated motion image, which is able to represent the motion information of the fetal heart more accurately. (b) Then by combining Rayleigh-trimmed filter and anisotropic diffusion in 3-dimensional space, a despeckling method is developed to suppress the speckle noise and emphasize the motion information for subsequent cardiac structure detection. (2) The active cardiac model is proposed for the detection of fetal heart structure, which is a key contribution of this paper. It takes into account both the structure and motion information of fetal hearts simultaneously. Both learning and inference of the active cardiac model are described in the paper. Experiments on seven ultrasound sequences demonstrate the effectiveness of the proposed method.