MRI梯度预加重模块的分时复用设计

A Time-Division Multiplexing Design for Gradient Preemphasis Module in Magnetic Resonance Imaging Scanner

为获得更优的成像质量和更快的成像速度,磁共振成像(MRI)系统的梯度预加重模块需要具有更多的补偿通道和调节参数,常规预加重模块的设计方案使现场可编程门阵列(FPGA)面临巨大的资源消耗.为解决高性能梯度预加重模块的资源消耗大的问题,本文提出了一种基于分时复用技术的梯度预加重实现方案,以常规方案1/44的资源实现了11通道×4组参数的梯度预加重模块.将该模块用于0.35 T MRI系统,测试了补偿前后的涡流曲线和磁共振图像,结果表明该模块有效降低了系统的涡流,减小了磁共振图像中的涡流伪影.

In magnetic resonance imaging(MRI),a gradient preemphasis module with more compensation channels and adjustable parameters is often desired for better imaging quality and faster imaging speed.With the conventional design,however,a high performance preemphasis module often requires high resource consumption such that the field programmable gate array(FPGA)may encounter huge resource overhead.In this study,a new gradient preemphasis implementation scheme based on time-division multiplexing was proposed.With the new design,an 11 channels×4 sets of parameters implementation could be achieved with only 1/44 of the resources required by the conventional scheme.To test the performance of the new implementation,eddy current curves and magnetic resonance images before and after preemphasis compensation were measured on a 0.35 T scanner and compared.The results demonstrated that the module could effectively reduce eddy currents and related artifacts on the images.