Ng T C, Glickson J D, Bendall M R
Magn Reson Med. 1984 Dec;1(4):450-62. doi: 10.1002/mrm.1910010405.
The depth pulse sequences theta;[2 theta(+/- x, +/- y)]2 and 2 theta;theta(+/- x);[2 theta(+/- x, +/- y)]2 have been implemented with a 20 mm diameter two-turn surface coil operating at 31P resonance (89.96 MHz). In these sequences theta refers to the pi/2 rf pulse at the center of the sensitive region of the coil, +/- x and +/- y denote the four orthogonal phases of the rf pulses, and ";" represents an optional brief delay (e.g., 4 microseconds) between pulses to facilitate switching between different phases. Localization of the sensitive region was demonstrated with phantom samples by in vivo monitoring of rat livers and detection of necrotic regions of subcutaneously implanted tumors. The inversion-recovery pulse sequence, 2 theta-tau-theta(+/- x);[2 theta(+/- x, +/- y)]2, where tau is a variable delay, was employed to measure the spin-lattice relaxation time of a selected region, which could be varied by changing the pulse width and the size of the surface coil.
深度脉冲序列theta;[2 theta(+/- x, +/- y)]2和2 theta;theta(+/- x);[2 theta(+/- x, +/- y)]2已通过一个直径为20毫米的双匝表面线圈实现，该线圈在31P共振（89.96兆赫兹）下工作。在这些序列中，theta指的是线圈敏感区域中心的π/2射频脉冲，+/- x和+/- y表示射频脉冲的四个正交相位，“;”表示脉冲之间的可选短暂延迟（例如4微秒），以便于在不同相位之间切换。通过对大鼠肝脏进行体内监测以及检测皮下植入肿瘤的坏死区域，用模型样品证明了敏感区域的定位。采用反转恢复脉冲序列2 theta-tau-theta(+/- x);[2 theta(+/- x, +/- y)]2（其中tau是可变延迟）来测量选定区域的自旋晶格弛豫时间，该时间可通过改变脉冲宽度和表面线圈的尺寸来改变。
