New Algorithms Of Motion Artifacts Correction In MR Images

In the recent years, there are urgent needs of the research on artifact correction in a magnetic resonance imaging (MRI) scan with its rapidly increasing great effect on clinic diagnosis and therapy. Especially, the research on motion artifact correction with post-processing algorithm is one of the most important fields in the case of that there are not very ideal methods to suppress MRI artifacts by means of the development of hardware and the pre-processing methods based on restraining motion happening. However, the state-of-the-art approaches on motion artifact correction are only implemented with the ideal motion model in the ideal conditions for the variety and complexity of the motion-happening causes in the real world. In this paper, a novel and fast algorithm for artifact correction, the inverse iterative correction (IIC) technique is proposed to reduce motion artifact due to simulated ideal rigid motion in MR images.In order to correct the phase errors due to all kinds of motions (including the periodic and the random), some inverse phase errors due to the simulated motion can be added to the raw data in k-space to counteract the original phase errors. If some simulated motion is right reverse to the real motion (same magnitude in opposite direction), the original phase errors can be surely cured.Thus, the histogram-based entropy function proposed in this article, utilizing the image own grey scale information in image domain, can not only better estimate the actual direction and displacement of patient motion as well, but also greatly improve the computational process.In the correction process of IIC, k-space lines are processed in the manner of direct correction-and-judgment according to continuity and consistency of the motion ,thereby, the change point of the motion can be properly estimate with the entropy criterion. The optimized correction strategy is verified to obviously improve the accuracy of correction and decrease the computational time.A lot of experiments and results of comparison with the other method are provided in this paper to demonstrate the feasibility and advantage of the proposed IIC method.