Monogenic Phase Based Optical Flow Computation for Myocardial Motion Analysis in 3D Echocardiography

We present a method for the analysis of heart motion from 3D cardiac ultrasound sequences. The algorithm exploits the monogenic signal theory, recently introduced as a N-dimensional generalization of the analytic signal. The displacement is computed locally by tracking variations in the monogenic phase. A 3D local affine displacement model accounts for typical motions as contraction/expansion and shearing. A coarse-to-fine B-spline scheme allows a robust and effective computation of the model parameters and a pyramidal refinement scheme helps in dealing with large motions. The independence of the monogenic phase on the local energy makes the algorithm insensitive to the time variant changes of image intensity that are often observed on echocardiographic sequences. The performance of our method is evaluated on 10 realistic simulated 3D echocardiographic sequences, showing good tracking accuracy (average error: 0.68±0.5 to 1.27±0.9 mm).