Radial Echo Volumar Imaging

项目摘要 该研究项目“径向回波体积成像”提出了MRI采集的发展， 基于一种新的通用非笛卡尔采样概念的快速运动校正重建方法 显像该技术扩展了回波平面成像（EPI），这是最广泛使用的快速MRI 是各种应用的标准方法，从功能性MRI到扩散， 灌注成像最近EPI也被证明是有前途的快速结构成像，包括 同步多参数MRI。大多数现代EPI方法基于体积成像方法 因为它们允许高的各向同性空间分辨率、每单位时间的改进的信噪比以及并行性， 沿第三维沿着的成像加速度。然而，体积成像的挑战是要求 由于梯度和生理限制导致运动灵敏度增加， 其他生理效应。 径向采样在分段采集方面具有若干优势，包括 由于对k空间的中心进行过采样而产生的固有自导航引起的运动。径向采样还具有 与允许大加速度的笛卡尔坐标相比，产生良性“条纹”混叠伪影的优势 以及并行成像方法的有效使用。径向采样的另一个优点是， 通过频率编码快速采样维度，从而获得更高的面内分辨率和更小的失真 低时间惩罚。在这个项目中，我们建议利用这些优势来开发创新的方法 对于快速和强大的大脑成像，这对于许多其他成像应用也很重要 包括身体核磁共振 该建议的科学前提是，可以通过使用以下三种方法获得最佳的快速MRI采集： 三维径向EPI轨迹和广义的基于模型的重建。我们提出了一个创新的 径向回波容积成像（REVI）采集通过沿第三方向添加梯度编码沿着创建 径向EPI采集，以创建SMS和3D旋转“Stack-of-Stars”采样，用于高并行成像 加速，同时允许时间和空间分辨率的最佳折衷。自我导航 径向轨迹的特性将提供运动鲁棒性，并且连续的黄金角旋转将 允许可变的时间分辨率和采集的重新排序。REVI的多回波特性还将 允许同时进行多参数结构扫描。所提出的技术不需要特殊的 硬件，并可以运行在任何扫描仪上的任何调查。

Project Summary This research project “Radial Echo Volumar Imaging” proposes the development of MRI acquisition and reconstruction methods based on a novel versatile non-Cartesian sampling concept for fast motion-corrected imaging. The technique expands upon Echo Planar Imaging (EPI), which is the most widely utilized fast MRI acquisition and is the standard method for various applications ranging from functional MRI to diffusion and perfusion imaging. Recently EPI has also been shown to be promising for rapid structural imaging including simultaneous multi-parametric MRI. Most modern EPI approaches are based on volumetric imaging methods as they permit high isotropic spatial resolution, improved Signal to Noise Ratio per unit time, and parallel imaging acceleration along the third dimension. A challenge of volumetric imaging however is the requirement for segmentation due to gradient and physiological limitations that leads to increased motion sensitivity and other physiological effects. Radial sampling offers several advantages with regards to segmented acquisitions including robustness to motion due to intrinsic self-navigation from oversampling the center of k-space. Radial sampling also has the benefit of producing benign “streaking” aliasing artifacts compared to Cartesian allowing for large accelerations and an efficient use of parallel imaging methods. A further advantage of radial sampling is that the in-plane dimension is sampled quickly by frequency encoding leading to higher in-plane resolution and less distortion with low time penalty. In this project we propose to utilize these advantages to develop innovative methodology for rapid and robust brain imaging that should also prove to be important for many other imaging applications including body MRI. The Scientific Premise of this proposal is that an optimal rapid MRI acquisition can be obtained by using three- dimensional radial EPI trajectories and generalized model-based reconstructions. We propose an innovative Radial Echo Volumar Imaging (REVI) acquisition created by adding gradient encoding along the third direction of a radial EPI acquisition to create SMS and 3D rotated “Stack-of-Stars” sampling for high parallel imaging acceleration while allowing for optimal tradeoffs in temporal and spatial resolutions. The self-navigation properties of the radial trajectories will provide motion robustness and continuous golden-angle rotation will permit variable temporal resolutions and reordering of the acquisition. The multi-echo nature of REVI will also allow for simultaneous multi-parametric structural scanning. The proposed technology requires no special hardware and can be run on any scanner by any investigator.