摘要
针对多次激发扩散磁共振成像中的运动伪影和偏共振伪影,本文提出了一种联合矫正方法,可以同时去除两种伪影,而且不需要额外采集运动导航数据和主磁场不均度图。该方法使用多次激发变密度螺旋线序列采集数据,通过自动偏共振矫正算法去除模糊,运动引入的相位误差在去除模糊的过程中采用直接法或迭代法矫正。在体磁共振成像实验表明,所提出的联合矫正方法可有效去除运动伪影和偏共振效应引起的图像模糊,获得结构清晰的成像结果,且不会增加扫描时间。
Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging(MRI),we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map.We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring.We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring.In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures.In addition,the scan time was not increased in applying the proposed method.
引文
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