Nägele T, Klose U, Grodd W, Nüsslin F, Voigt K
Department of Neuroradiology, University of Tübingen, Germany.
J Magn Reson Imaging. 1995 Jul-Aug;5(4):416-20. doi: 10.1002/jmri.1880050408.
An RF excitation pulse for three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) with a nonlinear excitation profile was numerically calculated under the condition of uniform vessel signal across the excitation volume (slab), and the superiority of the optform pulse as compared with conventional RF pulses and TONE pulses was demonstrated. For this purpose we acquired MRA of the lower leg and of the carotid and vertebral arteries in a 30-year-old healthy volunteer. Although the flow velocity ranges in these two anatomic locations are different by about a factor of 10, in both cases the corresponding optform pulse provided the best signal homogeneity at the highest level.
在激发体积（层面）内血管信号均匀的条件下，通过数值计算得出了用于三维（3D）时间飞跃（TOF）磁共振血管造影（MRA）且具有非线性激发轮廓的射频（RF）激发脉冲，并证明了优化脉冲相对于传统RF脉冲和TONE脉冲的优越性。为此，我们在一名30岁健康志愿者身上采集了小腿以及颈动脉和椎动脉的MRA。尽管这两个解剖位置的流速范围相差约10倍，但在这两种情况下，相应的优化脉冲均在最高水平上提供了最佳的信号均匀性。
