中文摘要：

定量磁化率成像（QSM）利用一般成像技术舍弃的相位信息得到局部磁场变化特性,通过复杂的场到源反演计算,可直接得到定量的磁化率图,它广泛应用于测量血氧饱和度、脑部微出血、铁沉积、组织钙化等方面.然而,梯度磁场中流动会引起相位错误,并且产生显著的流动伪影,最终得到错误的QSM图像.为了矫正流动的影响,该文在3 T磁共振系统上实现了三维多回波流动补偿梯度回波序列,并用该序列采集流动水模和志愿者颅脑数据.流动水模和颅脑数据均显示,流动补偿能够明显矫正相位错误,消除流动伪影.颅脑横断位QSM结果证明,流动补偿序列可以消除血液流动引起的QSM的错误,提高QSM的准确性.

英文摘要：

Venous blood oxygen saturation, cerebral microbleeds, iron deposition and tissue calcification can be measured by quantitative susceptibility mapping （QSM） via deconvolving the magnetic resonance （MR） phase signal. However, accurate estimation of phase signal and magnitude image in QSM may be affected by flow-induced errors in the presence of field gradient, which would ultimately lead to errors in the quantitative susceptibility map reconstructed. The aim of this study is to develop a method for correcting the flow-induced errors in phase signal and magnitude image in QSM. Flow-compensated data acquisition was achieved using a three-dimensional full flow compensated multi-echo gradient echo sequence. Phantom andin vivo experiments were carried out to validate the method proposed. The results of these experiments demonstrated that flow compensation can reduce errors in the phase signal and magnitude images. Improved quantitative susceptibility map of the superior sagittal sinus vein in human brain could be obtained with the proposed method.