时空编码单扫描磁共振成像的基本原理及重建方法

摘要

单扫描磁共振成像技术凭借其良好的时间分辨率，近年来在扩散成像、实时动态三维成像、功能成像等生物医学领域得到广泛应用。在众多单扫描磁共振成像方法中，回波平面成像(EPI)是最常用的一种方法，但它存在一些局限性，特别是在高场条件下，其对磁场不均匀及化学位移效应十分敏感。基于时空编码的单扫描磁共振成像新方法，其对不均匀磁场及化学位移伪影有很好的鲁棒性，并延续了EPI良好的时间分辨率。作者主要阐述时空编码单扫描成像方法的基本原理、特性，时空编码图像的超分辨重建方法及其在生物医学领域的应用。%AbstractIn recent years, single-shotmagnetic resonance imaging (MRI) has been widely used in biomedicine, such as diffusion imaging, functional imaging, and real-time three-dimensional imaging, owing to its excellent temporal resolution. Among single-shot MRI approaches echo-planar imaging (EPI) stands out most. However, EPI still faces several limitations, particularly as a result of ifeld inhomogeneity and of chemical shift effects that can become severein high fields. A novel single-shot MRI method was proposed based on spatiotemporal encoding, which provides a way to effectively alleviate the effects of field inhomogeneity and chemical shift while retaining high temporal-resolution character. In this work, we will review the principles and characters of spatiotemporally encoded MRI, and introduce the corresponding super-resolved reconstruction methods. In addition, we will present some major applications of spatiotemporally encoded MRI in biomedicine.