永磁微型磁共振成像仪的梯度线圈与图像质量

通过理论分析结合计算机仿真试验剖析了磁共振成像(MRI)中梯度场线性对图像质量影响的原理，在梯度场线性有缺陷的情况下，用实例和计算机模拟直观的展示了重建图像和模拟结果. 结合研发实践发现，在永磁微小口径、低场强用于鼠类等小动物成像情况下，对梯度场线性度的要求远高于文献中提出的指标. 依靠软件改进，图像没有本质的提高，尝试补偿技术耗时费力效果也不理想. 说明了对永磁微小口径成像仪研发线性度更好的梯度线圈是提高图像质量的关键技术之一. 揭示了在理想条件下普适的理论原理，在不同的实践条件下有不同的趋近理想条件要求. 将具有独立知识产权的高线性梯度线圈安装在自行研制的仪器上得到了较好的图像.

Gradient Coil of Permanent Magnet Mini-Magnetic Resonance Imager and Image Quality

Effects of gradient field linearity on the quality of images acquired on a permanent magnet mini-magnetic resonance imager were analyzed by theoretical analyses and numerical simulation. It was shown that gradient field with high linearity is a prerequisite to obtain high-quality images of small animals, such as mice, on permanent magnet, low field strength micro-magnetic resonance imagers. The gradient field linearity specification reported in the literature is too low to acquired high-quality mouse images. The image quality could not be improved by software compensation methods. The newly developed gradient field coil with high linear property and our independent intellectual property was also presented. The optimized gradient coil has been installed on our instrument, and yielded a better quality image.