Motion correction of magnetic resonance images using moments of spatial projections

Abstract

Magnetic resonance images reconstructed from a radial/projection acquisition are corrected for motion corruption caused by in-plane translational and in-plane rotational motion of an imaged subject using only the projection data itself. The method is based on the consistency properties of the 0th, 1st, and 2nd order moments of the spatial domain projections. In-plane translational motion is corrected by shifting/aligning the spatial projections according to the center of mass of each projection, which is calculated using the 0th and 1st moments. In-plane rotational motion is accounted for by determining the rotational motion time record using the 2nd moment information. The determination of the rotational motion time record using the 2nd moments is made possible by acquiring the successive MR projections at a view angle spacing that is substantially 45° and thus achieves sufficient linear independence. The translation-corrected spatial projections are reconstructed using the actual projection view angles, which are sum of the intended projection view angles plus the detected in-plane rotational motion time record. The calculation may also be performed in real-time during data acquisition in order to reacquire projections found to be too inconsistent due to through plane motion or other changes that are not in-plane rigid body motions or to acquire projections determined to be missing from the data set due to rotational motion.

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