Hood Maureen N, Ho Vincent B, Foo Thomas K F, Marcos Hani B, Hess Sandra L, Choyke Peter L
Department of Radiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA.
Magn Reson Imaging. 2002 Sep;20(7):543-9. doi: 10.1016/s0730-725x(02)00531-3.
Peripheral magnetic resonance angiography (MRA) is growing in use. However, methods of performing peripheral MRA vary widely and continue to be optimized, especially for improvement in illustration of infrapopliteal arteries. The main purpose of this project was to identify imaging factors that can improve arterial visualization in the lower leg using bolus chase peripheral MRA. Eighteen healthy adults were imaged on a 1.5T MR scanner. The calf was imaged using conventional three-station bolus chase three-dimensional (3D) MRA, two dimensional (2D) time-of-flight (TOF) MRA and single-station Gadolinium (Gd)-enhanced 3D MRA. Observer comparisons of vessel visualization, signal to noise ratios (SNR), contrast to noise ratios (CNR) and spatial resolution comparisons were performed. Arterial SNR and CNR were similar for all three techniques. However, arterial visualization was dramatically improved on dedicated, arterial-phase Gd-enhanced 3D MRA compared with the multi-station bolus chase MRA and 2D TOF MRA. This improvement was related to optimization of Gd-enhanced 3D MRA parameters (fast injection rate of 2 mL/sec, high spatial resolution imaging, the use of dedicated phased array coils, elliptical centric k-space sampling and accurate arterial phase timing for image acquisition). The visualization of the infrapopliteal arteries can be substantially improved in bolus chase peripheral MRA if voxel size, contrast delivery, and central k-space data acquisition for arterial enhancement are optimized. Improvements in peripheral MRA should be directed at these parameters.
外周磁共振血管造影（MRA）的应用正在不断增加。然而，进行外周MRA的方法差异很大，并且仍在不断优化，特别是在改善腘动脉以下动脉的显示方面。本项目的主要目的是确定使用团注追踪外周MRA可改善小腿动脉可视化的成像因素。18名健康成年人在1.5T MR扫描仪上进行成像。使用传统的三站团注追踪三维（3D）MRA、二维（2D）时间飞跃（TOF）MRA和单站钆（Gd）增强3D MRA对小腿进行成像。进行了观察者对血管可视化、信噪比（SNR）、对比噪声比（CNR）的比较以及空间分辨率比较。三种技术的动脉SNR和CNR相似。然而，与多站团注追踪MRA和2D TOF MRA相比，专用的动脉期Gd增强3D MRA的动脉可视化有显著改善。这种改善与Gd增强3D MRA参数的优化有关（快速注射速率为2 mL/秒、高空间分辨率成像、使用专用相控阵线圈、椭圆形中心k空间采样以及准确的动脉期定时用于图像采集）。如果体素大小、对比剂输送以及用于动脉增强的中心k空间数据采集得到优化，在团注追踪外周MRA中腘动脉以下动脉的可视化可得到显著改善。外周MRA的改进应针对这些参数。
