Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands.
J Magn Reson Imaging. 2010 Aug;32(2):482-8. doi: 10.1002/jmri.22243.
To quantitatively validate diffusion-weighted MRI (DW-MRI) applications, a hardware phantom containing crossing fibers at a sub-voxel level is presented. It is suitable for validation of a large spectrum of DW-MRI applications from acquisition to fiber tracking, which is an important recurrent issue in the field.
Phantom properties were optimized to resemble properties of human white matter in terms of anisotropy, fractional anisotropy, and T(2). Sub-voxel crossings were constructed at angles of 30, 50, and 65 degrees, by wrapping polyester fibers, with a diameter close to axon diameter, into heat shrink tubes. We show our phantoms are suitable for the acquisition of DW-MRI data using a clinical protocol.
The phantoms can be used to successfully estimate both the diffusion tensor and non-Gaussian diffusion models, and perform streamline fiber tracking. DOT (Diffusion Orientation Transform) and q-ball reconstruction of the diffusion profiles acquired at b = 3000 s/mm(2) and 132 diffusion directions reveal multimodal diffusion profiles in voxels containing crossing yarn strands.
The highly purpose adaptable phantoms provide a DW-MRI validation platform: applications include optimisation of acquisition schemes, validation of non-Gaussian diffusion models, comparison and validation of fiber tracking algorithms, and quality control in multi-center DWI studies.
为了定量验证扩散加权磁共振成像（DW-MRI）应用，我们提出了一种包含亚体素交叉纤维的硬件体模。它适用于从采集到纤维追踪的各种 DW-MRI 应用的验证，这是该领域一个反复出现的重要问题。
根据各向异性、分数各向异性和 T(2)，优化体模的特性使其类似于人白质的特性。通过将直径接近轴突直径的聚酯纤维缠绕在热缩管中，以 30、50 和 65 度的角度构建亚体素交叉。我们展示了我们的体模适用于使用临床方案采集 DW-MRI 数据。
体模可用于成功估计扩散张量和非高斯扩散模型，并进行流线纤维追踪。在 b = 3000 s/mm(2)和 132 个扩散方向采集的扩散分布的 DOT（扩散方向变换）和 q-球重建显示在包含交叉纱线的体素中存在多模态扩散分布。
高度专用的适应性体模提供了一个 DW-MRI 验证平台：应用包括采集方案的优化、非高斯扩散模型的验证、纤维追踪算法的比较和验证，以及多中心 DWI 研究的质量控制。
