Muthupillai Raja, Smink Jouke, Hong Steve, Ravindran Roshan, Lee Vei Vei, Flamm Scott D
Department of Radiology, St. Luke's Episcopal Hospital and Texas Heart Institute and Baylor College of Medicine, 6720 Bertner Ave., MC 2-256, Houston, TX 77030, USA.
AJR Am J Roentgenol. 2006 Jun;186(6):1669-75. doi: 10.2214/AJR.05.1012.
The purpose of this study was to assess the relative merits of reducing the scanning time of navigator-guided (NAV) coronary MR angiography by including, both independently and in combination, two time-saving strategies: k-space weighted motion-adapted gating (k-MAG) and sensitivity encoding (SENSE, factor = 2).
Coronary arteries of 21 healthy subjects were imaged with four NAV MR angiography sequences: conventional NAV sequence, NAV with the addition of SENSE, NAV with the addition of k-MAG, and NAV with a combination of SENSE and k-MAG. All imaging parameters including the magnetization preparation schemes, prescribed spatial resolution, and acquisition duration per R-R interval were identical for all techniques. The total scanning time, navigator efficiency, visible length of the coronary artery, and subjective image quality were used as metrics for evaluating the performance of the techniques.
The results show that the addition of k-MAG to NAV coronary MR angiography (with or without SENSE) improved scan efficiency and decreased scanning time by an average of 17% without compromising the length of coronary artery visible or the image quality. The addition of SENSE to the NAV technique (with or without k-MAG) reduces the scanning time by an average of 50%.
While the average image quality of coronary arteries was unaffected by the addition of k-MAG to navigator techniques, there was a slight reduction in image quality scores for the navigator sequence with SENSE. Identification of the proximal coronary arteries was not hampered by the addition of k-MAG, SENSE, or both to the NAV coronary MR angiography sequence.
本研究旨在评估通过独立或联合采用两种节省时间的策略，即k空间加权运动自适应门控（k-MAG）和灵敏度编码（SENSE，因子=2），来缩短导航器引导（NAV）冠状动脉磁共振血管造影扫描时间的相对优点。
对21名健康受试者的冠状动脉进行成像，采用四种NAV磁共振血管造影序列：传统NAV序列、添加SENSE的NAV序列、添加k-MAG的NAV序列以及联合SENSE和k-MAG的NAV序列。所有技术的所有成像参数，包括磁化准备方案、规定的空间分辨率以及每个R-R间期的采集持续时间均相同。总扫描时间、导航器效率、冠状动脉可见长度和主观图像质量用作评估技术性能的指标。
结果表明，在NAV冠状动脉磁共振血管造影中添加k-MAG（无论有无SENSE）可提高扫描效率，平均缩短扫描时间17%，同时不影响冠状动脉可见长度或图像质量。在NAV技术中添加SENSE（无论有无k-MAG）可平均缩短扫描时间50%。
虽然在导航器技术中添加k-MAG对冠状动脉的平均图像质量没有影响，但添加SENSE的导航器序列的图像质量评分略有降低。在NAV冠状动脉磁共振血管造影序列中添加k-MAG、SENSE或两者，均不妨碍对冠状动脉近端的识别。
