基于结构补偿的非线性全局场磁化率反演方法

A nonlinear total field inversion method with structural compensation for quantitative susceptibility mapping

定量磁化率成像是近年来磁共振成像领域中一项热门研究技术.定量磁化率成像技术通过逆向求解磁化率与相位的关系表达式,可定量地计算生物组织内部的信息变化,为相关的疾病诊断提供有效的辅助手段.定量磁化率成像需经过背景场去除、反演等多步计算,由此可导致误差的逐级传导并累加,从而降低定量磁化率重建精度.本文提出一种基于结构补偿的非线性全局场的定量磁化率反演算法,采用非线性形式实现单步重建磁化率图,并引入结构补偿法解决重建结果过平滑问题.实验结果表明,该方法有效抑制磁化率伪影并获得最佳的重建精度.

Quantitative susceptibility mapping(QSM)is one of the most popular studies of magnetic resonance imaging in recent years.QSM is to solve the field-to-source inverse problem to quantitatively calculate the tissue susceptibility using the phase map,which helps the diagnosis of relative diseases.The reconstruction of QSM is a complicated inverse problem with multiple steps,including background field removal and dipole field inversion.However,the multiple steps of calculation may propagate the error caused in any step and affect the accuracy of the results.A method based on nonlinear total field inversion with structure compensation is proposed in this text,which constructs QSM in one step.The results demonstrate that the proposed method can effectively suppress the susceptibility artifacts and calculate the susceptibility values more accurately.