Kneeland J B, Knowles R J, Cahill P T
Radiology. 1985 Apr;155(1):159-62. doi: 10.1148/radiology.155.1.3975397.
The user-selectable magnetic resonance imaging parameters involved in a multi-section multi-echo pulse sequence are described and their interrelationships explained. These parameters include repetition time (TR), echo delay time (TE), the number of sections (S), the number of echoes (E'), the time from the center of the last echo to the end of data acquisition (15 msec on the authors' system), and the time for T1 recovery. A simple mathematical relationship among these quantities, permitting easy calculation of the remaining parameters once a sufficient number have been specified, is given. In addition, a nomogram that permits rapid visual estimation of these parameters is presented. The effects of these choices and others is explained with respect to imaging time, region covered, and image contrast. Finally, the inherent trade-offs are illustrated in a clinical example involving the pelvis.
描述了多层面多回波脉冲序列中用户可选择的磁共振成像参数，并解释了它们之间的相互关系。这些参数包括重复时间（TR）、回波延迟时间（TE）、层面数（S）、回波数（E'）、从最后一个回波中心到数据采集结束的时间（作者系统上为15毫秒）以及T1恢复时间。给出了这些量之间的简单数学关系，一旦指定了足够数量的参数，就可以轻松计算其余参数。此外，还给出了一个列线图，可用于快速直观地估计这些参数。针对成像时间、覆盖区域和图像对比度，解释了这些选择及其他选择的影响。最后，通过一个涉及骨盆的临床实例说明了内在的权衡。
