DIFFUSION IMAGING ?MR NEUROIMAGING

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 这项研究的目标是为P41 RR09784“斯坦福高级磁共振技术中心”的研究人员和合作者继续完善和改进超高场(3T和7T)下的扩散张量成像(DTI)方法。来自各种研究的初步研究表明，DTI可以从需要几分钟的扫描中预测患者的认知和运动表现。至少沿六个非共线方向测量扩散。对于每个梯度方向，通常采集并平均四个图像。采集两幅无扩散加权的图像(b=0s/mm2)，得到一组b=0s/mm2的脑脊液归零的反转恢复(IR)图像，并用这些图像对扩散加权图像进行去翘曲，得到比使用非IRb=0图像更稳健的去翘曲。正义和更稳健的并行成像序列和后处理方法的发展加速了高场用于扩散研究的使用。关于各种扩散研究所需的最佳方案和序列参数集的问题正在调查中，其中包括更快速的中风评估方案和更高分辨率的白质束扩散张量成像方案。这项工作正在从3T转换到7T较新的实地研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this research continues to refine and improve the methodology of diffusion tensor imaging (DTI) at very high fields (3T and 7T) for the investigators and collaborators on the P41 RR09784 "Center for Advanced MR Technology at Stanford" effort. Preliminary studies from a variety of studies suggest that DTI may predict the cognitive and motor performances of a patient from scans requiring several minutes. Diffusion is measured along at least six non-collinear directions. For each gradient direction, typically four images were acquired and averaged. Two images with no diffusion weighting (b = 0s/mm2) are acquired and a set of Inversion Recovery (IR) images for CSF nulling are acquired with b = 0s/mm2; these images were used to unwarp the diffusion weighted images, which resulted in a more robust unwarping than using the non-IR b=0 images. The development of SENSE and more robust parallel imaging sequences and post-processing methods has accelerated the use of high fields for diffusion studies. Issues regarding the opimal protocol and set of sequence parameters needed for various diffusion studies are under investigation, which includes more rapid protocols for the assessment of stroke and more high resolution protocols for diffusion tensor imaging of white matter tracts. The effort is being translated from 3T to newer field field studies at 7T.