High-resolution Dynamic Contrast-enhanced MR Angiography

描述(由申请人提供)：本申请是一个名为“高分辨率时间分辨增强磁共振血管成像”项目的竞争性续展。最初的项目引入了这样一个概念，即在高对比度环境中，MR中的投影采集可能会被采样不足。重大的进步产生了成像技术，每单位时间的分辨率比傅立叶编码快四倍。几种快速扫描方法被开发出来，用于腹部、肺、心脏、外周、相位对比和T2加权成像。 这一竞争性更新的重点是欠采样技术，该技术通过大幅提高其时间分辨成像能力，进入高分辨率3D MR血管成像的下一步。原始项目对面内维度使用欠采样投影，在切片维度使用傅立叶编码。该项目获取所有方向的3D投影，使采样不足的能量更分散，更不引人注目。虽然加速系数与静态成像的原始项目相当，但数据集的时间处理允许加速系数随空间频率变化，从最低空间频率的40到最高空间频率的4。其他特点，包括各向同性分辨率，覆盖范围广，对对比剂到达时间不敏感，使其成为腹部对比剂增强磁共振血管成像的理想技术。该项目的目标包括：1)通过提高采样技术的效率来缩短采集时间；2)进一步开发和评估时间分辨成像的时间滤波算法；3)在猪肾动脉狭窄模型中验证该技术与X射线计算机旋转血管造影术的对比；4)在疑似腹部血管疾病的患者中验证该技术的准确性。这项工作的成功完成将产生一个磁共振检查，能够在不到5分钟的总检查时间内评估整个腹部血管系统。

DESCRIPTION (provided by applicant): This application is a competing renewal for a project titled "High-resolution time- resolved contrast-enhanced MR angiography". The original project introduced the concept that projection acquisitions in MR could be undersampled in high contrast environments. Significant progress produced imaging techniques that deliver four times faster resolution per unit time than Fourier encoding. Several fast scan methods were developed for abdominal, pulmonary, cardiac, peripheral, phase-contrast and T2- weighed imaging. The focus of this competing renewal is on undersampling techniques that take the next step in high resolution 3D MR angiography by dramatically increasing its capabilities for time-resolved imaging. The original project used undersampled projections for the in- plane dimensions and Fourier encoding in the slice dimension. This project acquires 3D projections in all orientations, making the undersampled energy more diffuse and less noticeable. While the speedup factor is comparable with the original project for static imaging, temporal processing of the dataset allows speedup factors that vary with spatial frequency from 40 at the lowest spatial frequencies to 4 at the highest ones. Other features, including isotropic resolution, broad coverage, and insensitivity to contrast arrival time, make this an ideal technique for abdominal contrast-enhanced MR angiography. The aims of the project include 1) shortening the acquisition time by increasing the efficiency of the sampling technique, 2) further developing and evaluating the temporal filtering algorithms for time-resolved imaging, 3) validating the technique against x-ray computed rotational angiography in a swine model of renal artery stenosis, and 4) validating the accuracy of the technique in patients with suspected abdominal vasculature disease. Successful completion of this work will produce an MR exam capable of evaluating the entire abdominal vasculature in a total exam time of less than five minutes.