McIntyre D J, Hennel F, Morris P G
CRC Biomedical NMR Group, St. George's Hospital Medical School, Tooting, London, United Kingdom.
J Magn Reson. 1998 Jan;130(1):58-62. doi: 10.1006/jmre.1997.1256.
An imaging sequence based on a spin-echo train has been developed which is free from geometric distortions in the imaging plane due to main field inhomogeneity. Such inhomogeneities, and chemical shifts, cause only a displacement in the selected slice, which is minimized by the use of high gradient strengths and short radiofrequency pulses. Additionally, variations in the radiofrequency field strength cause variations in the image amplitude but cause no other artifacts. This allows the use of low-flip-angle refocusing pulses, reducing the power deposition to levels which are safe in vivo at high field strengths. The sequence was implemented on a Bruker whole-body 3T system. Example images from a perfluorocarbon phantom and a human head are presented.
已经开发出一种基于自旋回波序列的成像序列，该序列不受主磁场不均匀性导致的成像平面几何畸变影响。此类不均匀性以及化学位移仅会导致所选切片出现位移，通过使用高梯度强度和短射频脉冲可将其降至最低。此外，射频场强的变化会导致图像幅度变化，但不会产生其他伪影。这使得可以使用低翻转角重聚焦脉冲，将功率沉积降低到在高场强下体内安全的水平。该序列在布鲁克全身3T系统上实现。展示了来自全氟碳体模和人类头部的示例图像。
