left ventricle wall motion estimation in echocardiographic images
The aim of this paper is to estimate motion of the left ventricle in echocardiographic image sequences of normal heart. Cardiac wall kinetic analysis requires two steps: (i) detection of the left ventricle boundaries in the image sequence, (ii) myocardial wall motion estimation. We have used the Level Set method to segment the left ventricle boundaries in 2D ultrasound images. This method implicitly represents the evolving contour by embedding it as the zero level of a hyper surface. The optical flow-based algorithm has been applied to estimate the left ventricle wall motion. The optical flow at time t and location P(x, y, t) is defined as the velocity of the image point. We propose in this paper a method for analyzing the wall motion cardiac. It consists of analyzing the temporal trajectory evolution for each pixel. So, by computing the velocity using the optical flow method, the trajectory of each pixel is tracking. The Hermite curves are used for plotting these trajectories. Thus, the assessment of the left ventricular contraction is then determined by observing the variation time curves of each pixel during a cardiac cycle. In order to carry out the wall motion analysis, the left ventricle was divided up in a simple way into seven segments. Such division is generated from three points positioned by the clinician.
wall motion estimation optical flow motion analysis echocardiography left ventricle segmentation level set approach