READOUT MOSAIC SEGMENTED DW EPI WITH PARALLEL IMAGING AND RPGM

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。 采用平行成像和RPGM的读出拼接分段DW EPI 萨曼莎·霍尔兹沃斯，斯特凡·斯卡雷，安德斯·诺德尔，雷克斯福德·纽布尔德，罗兰·班默 这项工作的目的是改善常规扩散加权EPI图像的失真特性和空间分辨率。EPI中的失真主要由沿相位编码方向在k空间中的缓慢遍历所决定，从而导致模糊和几何失真。 文献中提出了短轴螺旋桨EPI方案，作为高分辨率扩散成像的一种稳健的替代方案。通过加速沿相位编码方向的k空间遍历，可以显著减少失真伪影。当这种采样策略与并行成像相结合时，可以进一步减少这些伪影。与FSE-Propeller类似，该技术还具有固有的自导航优势--由此k空间的中心部分可用于提取导航器信息。然而，对于给定的目标分辨率，径向采样需要N/？多个采样点，因此与扫描时间损失相关。读出马赛克分割被认为是在短扫描时间内获得高分辨率EPI图像的一种替代方法。利用该方案，在读出方向上具有中断的多个k空间段被获取。对于每个分段，在k空间的中央分段中采样的第二个EPI读数(或导航器回波)被用于校正由于存在编码梯度和生理运动的DWI而引起的k空间移位。

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. Readout Mosaic Segmented DW EPI with parallel imaging and RPGM Samantha Holdsworth, Stefan Skare, Anders Nordell, Rexford Newbould, Roland Bammer The objective of this work is to improve the distortion characteristics and spatial resolution of conventional diffusion weighted EPI images. The distortions in EPI are mainly determined by the slow traversal through k-space along the phase encode direction which gives rise to blurring and geometric distortions. The short-axis propeller EPI scheme has been proposed in the literature as a robust alternative for high resolution diffusion imaging. By accelerating the k-space traversal along the phase encoding direction, distortion artifacts can be significantly diminished. Further reduction of these artifacts can be achieved when this sampling strategy is combined with parallel imaging. Similarly to FSE-Propeller, this technique also has the advantage of being inherently self navigated - whereby the center portion of k-space can be used to extract the navigator information. However, radial sampling requires N/¿ more sampling points for a given target resolution and is thus associated with a scan time penalty. Readout Mosaic Segmentation was suggested as an alternative approach for acquiring high resolution EPI images in a short scan time. With this scheme, multiple segments of k-space are acquired with a break in the readout direction. For each segment, a second EPI readout (or navigator echo) sampled in the central segment of k-space is used to correct for k-space shifts due to the presence of the DWI encoding gradients and physiological motion.