快速动态自动匀场技术在永磁磁共振成像系统中的实现

A Rapid Automated Shimming Method on Permanent Magnet MRI System

目的:为满足临床的需求,在万东医疗i_Open 0.36T永磁开放式磁共振成像MRI系统上发展实现一种快速动态自动匀场技术。方法:利用梯度回波成像技术得到恰当的匀场电流提高主磁场B0均匀度。结果:(1)视野(FOV)内的磁场均匀度显著提高。(2)匀场后MRI图像质量得到显著改善。结论:该方法能够满足临床动态实时匀场的需要。

Objective： To develop a rapid and automated shimming method in permanent magnet MRI system. Methods： The inhomogeneity distribution of main magnet field Bo was achieved on two sets of image datas obtained by special imaging pulse sequence after the problem of phase rewind had been solved. The shimming current required to improve the field homogeneity was calculated and then loaded to the MR imaging system. The contrast experiment with and without the shimming current had been conducted on 0.36T permanent MRI system. Results：（I）The homogeneity of field in the view （FOV） was improved significantly. （2） MR signal and image quality were improved significantly. Conclusions： The shimming technology can adequately satisfy the clinical application.