核磁共振成像系统中的数据处理与图像重建技术

Data Processing and Image Reconstruction Technology in the Magnetic Resonance Imaging System

本文首先介绍了一般磁共振成像系统数据采集部分的构成以及各部件的工作原理和作用，在此基础上介绍了通常的数据处理流程．本文特别分析了信号采集时产生截断效应的原因，给出了对应的截趾处理函数并分析了它们对图像质量的影响；仔细分析了相位误差产生的各种原因，提出了在采集过程中让实部信号与虚部信号共享通道以降低相位误差的方法以及通过计算进行相位校正的方法；研究了回波信号中的直流分量的成因以及它们对图像质量的影响，提出了简单和准确的处理方法。本文还简单介绍了磁共振成像系统中常用的图像处理技术。

In this paper, the structure of data acquisition of general MRI system and the conventional dataprocessing procedure are introduced at first. The causes which bring about the cut--off effect during data acquisitionare analysed 1 the apodization processing functions are given out and their effects on the image quality are analysed.The factors which contribu.te to the phase error are carefully examinedl after that a new method to reduce thephase error based on the innovative RF receiver circuits and a method of phase error correction based on the mathematics are presented. Then we analyze the reason which generates the direct current components of the echo signals and their effect on image and present a simple and accurate method to clear the direct current components ofthe echo signals. In addition. the application of some most useful image processing methods is demonstrated.