Maki J H, Prince M R, Londy F J, Chenevert T L
Department of Radiology, University of Michigan, Ann Arbor 48109-0030, USA.
J Magn Reson Imaging. 1996 Jul-Aug;6(4):642-51. doi: 10.1002/jmri.1880060413.
The optimum infusion timing and k-space ordering for obtaining gadolinium-enhanced three-dimensional MR angiograms was determined through computer modeling using temporal contrast characteristics obtained from patient gadolinium infusion data. The effects of bolus timing were evaluated by varying the relationship between peak intravascular gadolinium concentration and the time at which the center of k space was acquired (tck) for sequential and centric acquisition techniques. Flow phantom experiments were performed to validate the theoretical computations. Gadolinium concentration at the time of central k-space acquisition determines intravascular signal intensity. Artifacts, including vessel broadening and edge ringing, depend on the order in which k space is collected and on how rapidly the gadolinium concentration changes. Artifacts are greatest when the center of k space is acquired before the intravascular gadolinium peak. Application of the optimal infusion timing results in preferential arterial enhancement with a minimum of artifacts in patients undergoing MR angiography.
通过计算机建模，利用从患者钆注入数据获得的时间对比特征，确定了获取钆增强三维磁共振血管造影的最佳注入时间和k空间排序。通过改变血管内钆峰值浓度与采集k空间中心的时间（tck）之间的关系，对团注时间的影响进行了评估，用于连续采集技术和中心采集技术。进行了血流模型实验以验证理论计算。在采集中心k空间时的钆浓度决定了血管内信号强度。包括血管增宽和边缘振铃在内的伪影取决于采集k空间的顺序以及钆浓度变化的速度。当在血管内钆峰值之前采集k空间中心时，伪影最大。应用最佳注入时间可使接受磁共振血管造影的患者优先实现动脉增强，同时伪影最少。
