Tracking of cyclic motion with phase-contrast cine MR velocity data.
A method of computing trajectories of objects by using velocity data, particularly as acquired with phase-contrast magnetic resonance (MR) imaging, is presented. Starting from a specified location at one time point, the method recursively estimates the trajectory. The effects of measurement noise and eddy current-induced velocity offsets are analyzed. When the motion is periodic, trajectories can be computed by integrating in both the forward and backward temporal directions, and a linear combination of these trajectories minimizes the effect of velocity offsets and maximizes the precision of the combined trajectory. For representative acquisition parameters and signal-to-noise ratios, the limitations due to measurement noise are acceptable. In a phantom with reciprocal rotation, the measured and true trajectories agreed to within 3.3%. Sample trajectory estimates of human myocardial regions are encouraging.
Pelc
N J
NJ
Department of Radiology, Stanford University, Richard M. Lucas Center for Magnetic Resonance Imaging and Spectroscopy, CA 94305-5488, USA.
Drangova
M
M
Pelc
L R
LR
Zhu
Y
Y
Noll
D C
DC
Bowman
B S
BS
Herfkens
R J
RJ
D006321:Heart / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008961:Models, Structural; D009038:Motion; D009200:Myocardial Contraction