Detection of Motion at Variable Duration, Frequency and Amplitude in Projection Reconstruction Magnetic Resonance Imaging

Authors: Rik Van de WALLE, Ignage LEMAHIEU

Abstract: The presence of motion during MR imaging results in a distortion of the measured MR signals. When images are reconstructed from these distorted signals, severe ghosting and blurring are often seen. A new method to determine motion intervals in projection-reconstruction magnetic resonance imaging is presented. It does not use any a priori information concerning the motion and can be implemented on a standard personal computer or workstation. In the first section, the theory that forms the basis for the development of these methods, is described. The phase of the complex mean of a one-dimensional signal equals zero when no motion is present. When the depicted object is moving, it differs from zero. These conclusions are used to determine motion intervals in projection-reconstruction data. Both motion-detection methods prove to be able to detect motion intervals with an accuracy of one repetition time. The efficiency of this method was verified experimentally and by performing simolations, considering different motion types at a variable duration, frequency and amplitude.

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