Time-Resolved Lower Extremity MR Angiography using HighlY Constrained Back PRojec

使用高度约束背部项目的时间分辨下肢 MR 血管造影

• 批准号: 7568198
• 负责人: Frank Korosec
• 金额: $ 32.58万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7568198
• 关键词: Affect; Angiography; Arteries; Back; Blood Vessels; Characteristics; Contralateral; Data; Diagnostic; Doctor of Philosophy; Goals; Hybrids; Image; Individual; Limb structure; Location; Lower Extremity; Maps; Methods; Morphologic artifacts; Patients; Performance; Peripheral; Peripheral Vascular Diseases; Protocols documentation; Radial; Relative (related person); Research Personnel; Resolution; Series; Slice; Techniques; Time; Veins; base; cohort; experience; hemodynamics; improved; millimeter; programs; simulation; volunteer

DESCRIPTION (provided by applicant): We propose to use our recently-conceived HYPR method to develop an easy-to-implement, time-resolved, multi-station, contrast-enhanced peripheral MR angiography protocol that provides high spatial resolution angiograms with dramatically higher temporal resolution than is possible with current MR techniques. The HYPR method permits great improvements to temporal resolution in radial k-space acquisitions by producing time frames using only a very small subset of the total number of radial k-space lines necessary to satisfy the Nyquist criterion. Streak artifacts that would ordinarily result from constructing images using a severely reduced number of projections are ameliorated by constraining unfiltered back projected data to regions in which objects, in this case vessels, are known to exist. In order to determine the location of the vessels, a vessel map, or composite image, is produced using data from multiple time frames. This is possible because the data for each of the time frames is produced from radial k-space lines that are acquired at slightly different angles. The high SNR in the composite images dictates the SNR in the individual time frames, providing improved image quality relative to accelerated methods that are based solely on undersampling. Preliminary simulations suggest that good image quality may be achieved even when undersampling factors greater than 100 are used. In order to achieve our goal, we propose to develop three MRA techniques - 3D hybrid HYPR, 3D HYPR TRICKs, and 3D HYPR VIPR - and to evaluate and optimize the performance of these techniques using a series of simulation, phantom, and volunteer studies. Following this, the most successful HYPR peripheral vascular protocol will be compared with conventional x-ray DSA in a cohort of patients. Our central hypothesis is that HYPR will permit acquisition of very high temporal resolution contrast-enhanced multi-station peripheral MR angiograms, in which spatial resolution, SNR, and image quality are maintained at high levels.

描述（由申请人提供）：我们建议使用我们最近构想的HYPR方法来开发易于实施，时间分辨，多站，多站，对比度增强的外围MR血管造影协议，可提供高空间分辨率血管造影，具有高于当前MR技术的时间较高的时间分辨率。 HYPR方法允许通过仅使用满足nyquist标准所需的径向K空间线的一小部分来产生时间范围，从而对径向K空间采集的时间分辨率进行了极大的改进。通常，通过将未过滤后的投影数据限制为已知存在的物体存在的区域，可以通过将未过滤的投影数据限制为已知存在的区域，从而改善构造图像的条纹伪像可以改善。为了确定血管的位置，使用来自多个时间范围的数据生成容器图或复合图像。这是可能的，因为每个时间帧的数据都是从径向K空间线以略有不同的角度获取的。复合图像中的高SNR决定了单个时间范围中的SNR，相对于仅基于无底采样的加速方法提供了改进的图像质量。初步模拟表明，即使使用了大于100的不足采样因子，也可以达到良好的图像质量。为了实现我们的目标，我们建议开发三种MRA技术-3D Hybrid Hypr，3D Hypr Tricks和3D Hypr VIPR-并使用一系列模拟，幻影和志愿者研究评估和优化这些技术的性能。此后，将在一系列患者中将最成功的HYPR外周血血管方案与常规X射线DSA进行比较。我们的中心假设是HYPR将允许获取非常高的时间分辨率对比度增强的多站外周围MR血管造影，其中空间分辨率，SNR和图像质量保持高水平。