HIGH RESOLUTION CONTRAST ENHANCED MR ANGIOGRAPHY

这项工作的目标是调查小说的习得和 重建战略，以显著提高 增强磁共振血管成像(CE-MRA)。虽然行政长官- MRA比X-射线血管造影术(XRA)侵袭性小，而且不需要 电离辐射，XRA具有相当高的空间和时间 决议。我们的目标是开发、优化和评估新方法 使用投影重建(PR)技术提供更高的 单位时间的空间分辨率高于常规的傅立叶k空间 遍历。通过限制数量将提高效率 获取投影角度。X射线计算机中的稀疏采样 使用滤波反投影(FBP)的断层扫描(CT)会产生“杂波” 相对于组织中的微小差异而言较大的伪影 CT显示衰减。初步结果表明，大型 CE-MRA增强血管与静止组织的信号差异 使这些公关构件在某些应用程序中可接受。自.以来 船只产生杂波伪影，对伪影的估计可以 会被生成，然后在后处理中减少。这一公关策略 将扫描时间初步缩短为原来的1/4。再加上 高时态K-空间调度与重构方法 分辨率，可以在几个关键时刻提供高空间分辨率 在动脉增强曲线上的所有图像。三大主线 将开发3DPR采集技术，以提供灵活性 在规定空间和时间分辨率时。拟议中的工作 包括模拟和模型实验，以优化收购 战略和量化他们的表现。伪像的算法 在此期间，将进一步调查和完善削减 实验也是如此。优化后的技术将应用于临床。 在颈动脉、肺和腹部进行评估。成功 这项工作的完成将使CE-MRA成为 更具侵袭性的X射线DSA技术。

The goal of this work is to investigate novel acquisition and reconstruction strategies to significantly increase the performance of contrast-enhanced magnetic resonance angiography (CE-MRA). Though CE- MRA is less invasive than X-ray angiography (XRA) and utilizes no ionizing radiation, XRA has considerably higher spatial and temporal resolution. Our aim is to develop, optimize, and evaluate new methods using projection reconstruction (PR) techniques that deliver higher spatial resolution per unit time than conventional Fourier k-space traversals. Efficiency will be increased by limiting the number of projection angles acquired. Sparse sampling in X-ray computed tomography (CT) using filtered back projection (FBP) produces "clutter" artifacts which are large relative to the small differences in tissue attenuation displayed by CT. Preliminary results suggest that the large signal difference between enhanced vessels and static tissue in CE-MRA make these PR artifacts acceptable in some applications. Since the vessels generate the clutter artifacts, estimates of the artifacts can be generated and later reduced in post-processing. This PR strategy provides a preliminary four-fold reduction in scan time. Coupled with k-space scheduling and reconstruction methods for high temporal resolution, high spatial resolution can be provided at several key time frames throughout the arterial contrast enhancement curve. Three main 3DPR acquisition techniques will be developed to provide flexibility when prescribing spatial and temporal resolution. The proposed work includes simulations and phantom experiments to optimize the acquisition strategies and quantify their performance. Algorithms for artifact reduction will be further investigated and refined during these experiments as well. The optimized techniques will be clinically evaluated in the carotid arteries, lungs and abdomen. Successful completion of this work will place CE-MRA as a stronger competitor to the more invasive X-ray DSA technique.