Development of High-Performance Multi-Contrast Echo Planar Imaging

脑部的定量T1 MRI提供了对脑组织健康状况的有价值的见解。 为了估计T1，用多个反转时间（TI）值采集图像切片，然后 测量的强度相对于TI值的变化被t到MR自旋弛豫模型以提取 潜在的定量T1恢复值。目前，T1标测的黄金标准是 反转恢复自旋回波（IR-SE）。然而，这个MRI序列需要一个非常长的时间。 数据采集时间，这妨碍了临床采用。 采用快速MR成像可以减少反转恢复数据采集时间 回波平面成像（EPI）和EPI采集中的创造性切片排序等方法 形成完整成像卷的数据。在1000 MRI场强下，7特斯拉，T1标测，使用 EPI受到固有成像伪影的限制。一个主要的伪影是EPI重影， 作为从原始源位置移位的测量图像的副本。在某些情况下， 这些移位的副本可以产生涟漪伪影 会话，将时间不稳定性引入数据。这些文物出现在更突出的 更高的磁场强度，特别是当成像大脑深处的结构时。 该提案旨在改进和验证一种新的，新颖的快速T1映射方法， 超高场，称为多重反转EPI（MI-EPI）。在目标1中，我们寻求整合我们最近的 我们所展示高性能EPI技术减少了固有的EPI成像伪影， 包括双极性GRAPPA、双极性切片GRAPPA和FLEET，转换为自旋回波（SE） 多反转同时多切片（SMS）EPI序列的读出变体。我们寻求 证明定量T1图可以一致和稳健地从多个 使用SE MI-EPI收集的反转时间数据。然后，我们将进一步扩展我们的高性能 将EPI技术转化为SMS-EPI扩散加权序列，并开发出兼容DICOM的 图像重建框架，用于从定量T1生成FLAIR和MPT图像 地图最后，我们寻求开发一种分段的自旋回波MI-EPI序列， 失真和提高空间分辨率。在目标2中，我们寻求将上述所有内容联合收割机结合起来， 一个10分钟的，所有基于EPI的，全脑神经系统检查方案。 我们的提案是否成功，将通过描述改进的能力来确定艾德 T1标测应用程序中的图像质量和与基础解剖结构的清晰度。的 该项目的成功完成将直接改善神经影像学研究， 高质量的T1-Mapping和短时间的全脑神经系统检查，7 T场强。

Quantitative T1 MRI of the brain provides valuable insight into the health status of brain tissue. To estimate T1, an image slice is acquired with multiple inversion time (TI) values, and then the variation in measured intensities versus TI values are t to a MR spin-relaxation model to extract the underlying quantitative T1 recovery value. The gold standard for T1 mapping is currently Inversion-Recovery Spin Echo (IR-SE). However, this MRI sequence requires a prohibitively long data acquisition time, which prevents clinical adoption. Inversion-recovery data acquisition time can be reduced by both adopting fast MR imaging methods such as echo planar imaging (EPI) and creative slice ordering in the acquisition of EPI data that form the full imaged volume. At ultrahigh MRI eld strength, 7 Tesla, T1-Mapping using EPI is limited by inherent imaging artifacts. One dominant artifact is EPI ghosting, which manifests as copies of the measured image displaced from the original source location. In certain cases, these displaced copies can create ripple artifacts that may change over the course of an imaging session, introducing temporal instability into the data. These artifacts appear more prominently at higher magnetic eld strength, particularly when imaging structures deep within the brain. This proposal seeks to improve and validate a new, novel method for rapid T1-Mapping at ultra-high eld, named Multiple-Inversion EPI (MI-EPI). In Aim 1, we seek to integrate our recent high-performance EPI technology that we have shown reduce inherent EPI imaging artifacts, including Dual-Polarity GRAPPA, Dual-Polarity slice-GRAPPA, and FLEET, into a spin-echo (SE) readout variant of the Multi-Inversion Simultaneous Multi-Slice (SMS) EPI sequence. We seek to demonstrate that quantitative T1 maps can be consistently and robustly generated from multiple inversion-time data collected using SE MI-EPI. We then will further extend our high-performance EPI technology into an SMS-EPI diffusion weighted sequence, and develop an DICOM-compatible image reconstruction framework to generate FLAIR and MPRAGE images from the quantitative T1 maps. Finally, we seek to develop a segmented spin-echo MI-EPI sequence to reduce geometric distortion and improve spatial resolution. In Aim 2, we seek to combine all of the above to implement a 10 minute, all EPI based, whole-brain neurological examination protocol. The success of our proposal will be identi ed by the ability to characterize an improvement in image quality and delity with the underlying anatomy in the T1-Mapping application. The successful completion of this project will directly improve neuroimaging studies, by enabling rapid, high quality T1-Mapping and a short, whole-brain neurological exam at 7T eld strength.