Departments of Biomedical Engineering and Radiology, Northwestern University, Chicago, Illinois, USA.
Magn Reson Med. 2010 Apr;63(4):970-8. doi: 10.1002/mrm.22246.
Slow contrast infusion was recently proposed for contrast-enhanced whole-heart coronary MR angiography. Current protocols use Cartesian k-space sampling with empiric acquisition delays, potentially resulting in suboptimal coronary artery delineation and image artifacts if there is a timing error. This study aimed to investigate the feasibility of using time-resolved three-dimensional projection reconstruction for whole-heart coronary MR angiography. With this method, data acquisition was started simultaneously with contrast injection. Sequential time frames were reconstructed by employing a sliding window scheme with temporal tornado filtering. Additionally, a self-timing method was developed to monitor contrast enhancement during a scan and automatically determine the peak enhancement time around which optimal temporal frames were reconstructed. Our preliminary results on six healthy volunteers showed that by using time-resolved three-dimensional projection reconstruction, the contrast kinetics of the coronary artery system throughout a scan could be retrospectively resolved and assessed. In addition, the blood signal dynamics predicted using self-timing was closely correlated to the true dynamics in time-resolved reconstruction. This approach is useful for optimizing delineation of each coronary artery and minimizing image artifacts for contrast-enhanced whole-heart MRA.
慢对比输注最近被提议用于对比增强全心冠状动脉磁共振血管造影。当前的协议使用笛卡尔 k 空间采样和经验采集延迟，如果存在定时误差，可能会导致冠状动脉显影和图像伪影不理想。本研究旨在探讨使用时间分辨三维投影重建进行全心冠状动脉磁共振血管造影的可行性。使用这种方法，在开始注射对比剂的同时开始数据采集。通过使用时间龙卷风滤波的滑动窗口方案来重建连续的时间帧。此外，还开发了一种自定时方法来监测扫描期间的对比增强，并自动确定最佳时间帧重建的峰值增强时间。我们对六名健康志愿者的初步结果表明，通过使用时间分辨三维投影重建，可以回顾性地解决和评估整个扫描过程中冠状动脉系统的对比剂动力学。此外，使用自定时预测的血液信号动力学与时间分辨重建中的真实动力学密切相关。这种方法可用于优化每个冠状动脉的描绘并最小化对比增强全心 MRA 的图像伪影。
