Brain Imaging and Analysis Center, School of Medicine, Duke University, 2424 Erwin Rod, Suite 501, Durham, NC 27705, USA.
Neuroimage. 2012 Jan 16;59(2):1290-8. doi: 10.1016/j.neuroimage.2011.07.096. Epub 2011 Aug 16.
Gradient-echo MRI has revealed anisotropic magnetic susceptibility in the brain white matter. This magnetic susceptibility anisotropy can be measured and characterized with susceptibility tensor imaging (STI). In this study, a method of fiber tractography based on STI is proposed and demonstrated in the mouse brain. STI experiments of perfusion-fixed mouse brains were conducted at 7.0T. The magnetic susceptibility tensor was calculated for each voxel with regularization and decomposed into its eigensystem. The major eigenvector is found to be aligned with the underlying fiber orientation. Following the orientation of the major eigenvector, we are able to map distinctive fiber pathways in 3D. As a comparison, diffusion tensor imaging (DTI) and DTI fiber tractography were also conducted on the same specimens. The relationship between STI and DTI fiber tracts was explored with similarities and differences identified. It is anticipated that the proposed method of STI tractography may provide a new way to study white matter fiber architecture. As STI tractography is based on physical principles that are fundamentally different from DTI, it may also be valuable for the ongoing validation of DTI tractography.
梯度回波 MRI 揭示了脑白质中的各向异性磁敏感性。这种磁敏感性各向异性可以用磁化率张量成像 (STI) 进行测量和描述。在这项研究中，提出了一种基于 STI 的纤维追踪方法，并在小鼠大脑中进行了验证。在 7.0T 下对灌注固定的小鼠大脑进行了 STI 实验。对每个体素进行正则化计算磁敏感性张量，并将其分解为特征系统。发现主要特征向量与潜在纤维方向一致。沿着主要特征向量的方向，我们能够在 3D 中绘制出独特的纤维通路。作为比较，还对同一标本进行了扩散张量成像 (DTI) 和 DTI 纤维追踪。通过比较，探索了 STI 和 DTI 纤维束之间的关系，确定了它们的相似之处和不同之处。预计 STI 纤维追踪方法可能为研究白质纤维结构提供一种新方法。由于 STI 纤维追踪基于与 DTI 根本不同的物理原理，因此它对于 DTI 纤维追踪的持续验证也可能具有价值。
