Hackney D B, Lenkinski R E, Grossman R I, Zimmerman R A, Goldberg H I, Bilaniuk L T, Young S C, Nowell M A, Kemp S S
Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104.
J Comput Assist Tomogr. 1988 Jan-Feb;12(1):171-4. doi: 10.1097/00004728-198801000-00040.
Fast low-angle multiecho (FLAME) imaging uses partial flip angles of less than 90 degrees with 180 degrees radiofrequency refocusing pulses. The partial flip angle permits imaging with shorter repetition time (TR) values on the order of 750-1,000 ms for 30 degrees angles with image contrast characteristics identical to those obtained with conventional 90-180 degrees schemes and TRs on the order of 2,500 ms. The approximately threefold reduction in imaging time is accompanied by a decrease in signal-to-noise ratio. In many circumstances, however, this trade-off may produce entirely acceptable images of the CNS at a significant reduction in imaging time.
快速低角度多回波(FLAME)成像使用小于90度的部分翻转角以及180度射频重聚焦脉冲。部分翻转角允许在750 - 1000毫秒量级的较短重复时间(TR)值下进行成像,对于30度角而言,其图像对比特征与使用传统90 - 180度序列及2500毫秒量级的TR所获得的相同。成像时间大约减少了三倍,但同时信噪比也会降低。然而,在许多情况下,这种权衡可能会在显著减少成像时间的同时产生完全可接受的中枢神经系统图像。