Abstract

The reconstruction of tomograms in magnetic resonance imaging (MRI) has been considered for different degrees of transverse gradient instability of magnetic field. A method for minimizing the impact of deviation of resultant points of signal measurements from regular positions on the quality of reconstructed tomograms was proposed. The ultimate values of parameters of field gradient instability with due regard for the possibility of their compensation were determined in processing of real tomographic images. A series of multiple procedures for generating signals under conditions of different spread of magnetic field components and subsequent reconstruction was conducted for estimating the impact of instability on the accuracy of final results. It has been shown that the building and joint analysis of several tomographic distributions for different angles of orientation of magnetic gradient system for the transverse phase-frequency coding of response signal improves the structure of diagnostic data. In solving the inverse problem of restoring the spin distributions, the compensation of distortions caused by the irregularity of grid for forming data through combining an array of measurements performed under different conditions was obtained. The estimation of qualitative parameters of reconstruction of two-dimensional tomographic high-resolution distributions was conducted for the case of measuring the response signal for two and three orientations of its transverse coding.

中文翻译：

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用于磁共振成像数据正则化的梯度磁场信号相频编码修改

摘要

磁共振成像 (MRI) 中的断层图像重建已被考虑用于不同程度的磁场横向梯度不稳定性。提出了一种最小化信号测量结果点与规则位置的偏差对重建断层图像质量的影响的方法。场梯度不稳定性参数的最终值在适当考虑其补偿的可能性的情况下在真实断层摄影图像的处理中确定。为了估计不稳定性对最终结果精度的影响，进行了一系列在不同磁场分量传播条件下生成信号和随后重建的多重程序。已经表明，对于响应信号的横向相频编码，针对磁梯度系统的不同取向角度的若干层析成像分布的构建和联合分析改进了诊断数据的结构。在解决自旋分布恢复的逆问题中，通过组合不同条件下进行的一系列测量，获得了对形成数据的网格不规则造成的失真的补偿。针对测量其横向编码的两个和三个方向的响应信号的情况，进行了二维断层扫描高分辨率分布重构的定性参数的估计。