A Multi-Scale Phase-Based Optical Flow Method for Motion Tracking of Left Ventricle

Abstract

Quantitative analysis of cardiac motion is important in assessing ventricular function. Multi-scale phase-based optical flow (OF) method for motion tracking of the left ventricle (LV) is presented for tagged magnetic resonance (MR) image sequence. Two phase images, which contain the information about the motion orthogonal to the tag lines, are derived from harmonic phase (HARP) technique for each frame. The two phase images rather than brightness are used as sources in the OF method to calculate displacement flow, since the phase is a property of the tissue that remains constant over a cardiac cycle. The Multi-scale algorithm can improve the accuracy and be used to measure large motion. The effectiveness of the method and the accuracy of motion tracking are validated through simulated data and real tagged data. The results show that this method can also achieve acceptable accuracy of motion tracking with little sensitivity to tag fading