Reduction of Artifacts Caused byTranslational and Rotational

| We present a new projection reconstruction magnetic resonance (MR) imaging sequence for the correction of artifacts caused by transla-tional and/or rotational rigid motion. We performed brain imaging during which a volun-teer's head was moving in a combined translational and rotational rigid way. The MR signals were ordered in an interleaved way in order to reduce the motion sensitivity drastically. By using an original motion-determination technique, it was possible to determine the limited number of MR signals being distorted by motion with an accuracy of one repetition time. These signals were modiied in order to correct for the translational and rotational motion that was present during the signal acquisition by calculating the translational shift and rotation angle of the object. Finally, it was possible to calculate a modiied raw-data set that contained only very small distortions caused by motion. In conclusion, motion parameters are extracted from the measured raw data and used to calculate a set of raw data. By using the latter raw data set, it is possible to reconstruct the corresponding MR image containing no relevant motion artifacts.