Talagala S L, Jungreis C A, Kanal E, Meyers S P, Foo T K, Rubin R A, Applegate G R
Pittsburgh NMR Institute, Department of Radiology, University of Pittsburgh Medical Center, PA 15213, USA.
J Magn Reson Imaging. 1995 May-Jun;5(3):317-23. doi: 10.1002/jmri.1880050316.
Magnetic resonance angiography is most commonly performed with the three-dimensional (3D) time-of-flight (TOF) technique. As currently practiced, this requires long image acquisition times (5-10 minutes). The authors show that the acquisition time of 3D TOF images can be reduced to less than 1 minute by using a very short TR (< 10 msec). Under normal flow conditions, the major vessels of the circle of Willis were consistently well demonstrated on these fast 3D TOF images. Signal saturation was observed in studies of patients with abnormal blood flow. In those cases, it was demonstrated that serial acquisition of fast 3D TOF data during and after contrast agent administration could be used to overcome the saturation effects. Time-resolved fast 3D TOF imaging during and after contrast agent administration can also provide qualitative assessment of flow and may depict other features that cannot be observed in TOF studies with long imaging times.
磁共振血管造影最常用三维（3D）时间飞跃（TOF）技术进行。按照目前的做法，这需要较长的图像采集时间（5 - 10分钟）。作者表明，通过使用非常短的TR（<10毫秒），3D TOF图像的采集时间可缩短至不到1分钟。在正常血流条件下， Willis环的主要血管在这些快速3D TOF图像上始终能得到很好的显示。在血流异常患者的研究中观察到了信号饱和现象。在这些情况下，已证明在注射造影剂期间及之后连续采集快速3D TOF数据可用于克服饱和效应。在注射造影剂期间及之后进行时间分辨快速3D TOF成像还可提供血流的定性评估，并可能描绘出在长时间TOF研究中无法观察到的其他特征。
