VALIDATION OF CINE PHASE-CONTRAST MR-IMAGING FOR MOTION ANALYSIS

The accuracy of cine phase-contrast magnetic resonance (MR) imaging fo r motion analysis was evaluated. By using a rotating phantom and postp rocessing algorithm for phase tracking, errors arising during data acq uisition were identified and compensation methods were developed. A sp atially varying background phase offset in the velocity images was fou nd to be due to eddy current-induced fields. The magnitude of the offs et was in the range of 0.20 cm/sec, which is of the same order of magn itude as cardiac contractile velocities. Background offset is thus an important source of error in tracking cardiac motion. Study of differe nt tracking algorithms revealed the need for an integration scheme usi ng motion terms higher than velocity. Also, considerable improvement i n the accuracy and stability of the predicted trajectories was obtaine d by averaging the trajectories proceeding both forward and backward i n time from the starting point. With the algorithm developed, the moti on of the phantom was tracked through a complete rotation of the phant om to an accuracy of 2 pixels.