Brain Imaging and Analysis Center, School of Medicine, Duke University Durham, NC, USA ; Department of Radiology, Duke University Durham, NC, USA.
Front Integr Neurosci. 2013 Mar 6;7:11. doi: 10.3389/fnint.2013.00011. eCollection 2013.
Diffusion MRI has become an invaluable tool for studying white matter microstructure and brain connectivity. The emergence of quantitative susceptibility mapping and susceptibility tensor imaging (STI) has provided another unique tool for assessing the structure of white matter. In the highly ordered white matter structure, diffusion MRI measures hindered water mobility induced by various tissue and cell membranes, while susceptibility sensitizes to the molecular composition and axonal arrangement. Integrating these two methods may produce new insights into the complex physiology of white matter. In this study, we investigated the relationship between diffusion and magnetic susceptibility in the white matter. Experiments were conducted on phantoms and human brains in vivo. Diffusion properties were quantified with the diffusion tensor model and also with the higher order tensor model based on the cumulant expansion. Frequency shift and susceptibility tensor were measured with quantitative susceptibility mapping and susceptibility tensor imaging. These diffusion and susceptibility quantities were compared and correlated in regions of single fiber bundles and regions of multiple fiber orientations. Relationships were established with similarities and differences identified. It is believed that diffusion MRI and susceptibility MRI provide complementary information of the microstructure of white matter. Together, they allow a more complete assessment of healthy and diseased brains.
扩散 MRI 已成为研究白质微观结构和大脑连接的不可或缺的工具。定量磁化率映射和磁化张量成像（STI）的出现为评估白质结构提供了另一种独特的工具。在高度有序的白质结构中，扩散 MRI 测量由各种组织和细胞膜引起的水流动性受阻，而磁化率对分子组成和轴突排列敏感。整合这两种方法可能会对白质的复杂生理学产生新的认识。在这项研究中，我们研究了白质中扩散和磁化率之间的关系。在体模和人体大脑上进行了实验。使用扩散张量模型和基于累积展开的高阶张量模型来量化扩散特性。使用定量磁化率映射和磁化张量成像测量频率偏移和磁化率张量。在单纤维束区域和多纤维取向区域比较和关联这些扩散和磁化率量。确定了相似性和差异性。据信，扩散 MRI 和磁化率 MRI 提供了白质微观结构的互补信息。它们共同允许对健康和患病的大脑进行更全面的评估。
