DIFFUSION IMAGING ?MR NEUROIMAGING

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 本研究的目标是继续完善和改进P41 RR 09784“斯坦福大学先进MR技术中心”研究人员和合作者在极高场（3 T和7 T）下的弥散张量成像（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。沿至少六个非共线方向沿着测量扩散。对于每个梯度方向，通常采集四个图像并取平均值。采集了两幅无扩散加权（B = 0 s/mm 2）的图像，并采集了一组B = 0 s/mm 2的CSF归零反转恢复（IR）图像;这些图像用于展开扩散加权图像，这导致比使用非IR B=0图像更稳健的展开。 SENSE和更强大的并行成像序列和后处理方法的发展加速了高场扩散研究的使用。各种弥散研究所需的optophan协议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协议和更高分辨率的白色物质束的弥散张量成像协议。这项工作正在从3 T转换到7 T的新现场研究。

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.