A Coupled Active Contour Model for Myocardial Tracking in Contrast Echocardiography

Contrast echocardiography has been proposed as an indicator of myocardial perfusion in a non-invasive way. Reperfusion curves can be obtained by destroying all the microbubbles using an ultrasound pulse with high mechanical index and acquiring images during the reperfusion process. Quantitative parameters describing the process can be obtained from the curves. To analyze the complete myocardium, we propose a method for the simultaneous segmentation and tracking of endocardium and epicardium in myocardial contrast echocardiography sequences. The model consists of two active contours, guided by optical flow estimates. The evolutions of the two contours are coupled geometrically using a novel scheme that imposes stability in wall thickness, to deal with low contrast regions in the epicardial contour. Both a closed and an open model have been designed, to account for the different acquisition views used routinely. The model has been evaluated with experimental and clinical sequences, comparing the results with manual segmentations carried out by an expert.