Robust estimation of planar rigid body motion in magnetic resonance imaging

In magnetic resonance imaging, some schemes require slow data acquisition in order to achieve acceptable spatial resolution and signal-to-noise ratio. However, long scanning periods allow patient motion to distort the reconstructed images. In cases of planar rigid body motion, rotational and translational transformations can be assumed to model the patient motion. In this study, we develop a novel technique for estimating the parameters of these transformations. It is based on fixing two markers to the patient and using a post-processing algorithm to estimate the location of these two markers during the scan time. The key factor in this algorithm is to incorporate a priori information about the geometric shape of the markers to achieve accurate estimation. Computer simulation results confirmed the ability of the algorithm to estimate the unknown parameters.