DIFFUSION TENSOR IMAGING: A CLINICAL DTI PROTOCOL

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。本研究的目标是继续完善和改进扩散张量成像（DTI）的研究人员和合作者对P41 RR09784 ？斯坦福大学高级磁共振技术中心？努力。弥散张量成像（DTI）是一种很有前途的评估脑白质结构完整性和连通性的新技术。我们已经将DTI添加到各种各样的脑MR协议中，如急性和慢性中风，创伤，多发性硬化症，早产儿以及许多精神病学协议。各种研究的初步结果表明，DTI可以通过这4分钟的扫描预测患者的认知和运动表现。沿六个非共线方向测量扩散。对于每个梯度方向，获取4幅图像并取平均值。获取2张无扩散加权图像（b = 0s/mm2），获取一组用于脑脊液空化的反演恢复（IR）图像（b = 0s/mm2）；这些图像被用来解除扩散加权图像的扭曲，这导致比使用非ir b=0图像更健壮的解除扭曲。DTI序列需要4分钟。DTI的一个更有趣的方面涉及到大脑中白质方向的三维可视化。虽然分数各向异性图通常以灰度显示，但实际的水质子扩散矢量可能被覆盖到彩色图上。我们一直在评估以有意义和信息形式显示复杂质子扩散信息的各种方法。其中一种方法是对原始数据进行过采样，然后在三维配色方案和光纤跟踪算法模型中放置矢量流。

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) for the investigators and collaborators on the P41 RR09784 ?Center for Advanced MR Technology at Stanford? effort. Diffusion tensor imaging (DTI) is a promising new technique for the assessment of white matter (WM) structural integrity and connectivity. We have added DTI to a wide variety of brain MR protocols such as acute and chronic stroke, trauma, multiple sclerosis, premature babies as well as to a number of psychiatric protocols. Preliminary results from a variety of studies suggest that DTI may predict the cognitive and motor performances of a patient from this 4-minute scan. Diffusion is measured along six non-collinear directions. For each gradient direction, four images were acquired and averaged. Two images with no diffusion weighting (b = 0s/mm2) were acquired and a set of Inversion Recovery (IR) images for CSF nulling were 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 DTI sequence requires 4 minutes. One of the more interesting aspects of DTI involves the 3-D visualization of the white matter orientation in the brain. While the fractional anisotropy maps are typically displayed in a gray scale, the actual water proton diffusion vectors may be overlaid onto a color map. We have been evaluating various ways of displaying the complex proton diffusion information in a meaningful and informative format. One such approach involves oversampling of the original data followed by a vector stream placed within a 3-D color scheme and in models for fiber tracking algorithms.