Foley W D, Kneeland J B, Cates J D, Kellman G M, Lawson T L, Middleton W D, Hendrick R E
Department of Radiology, Medical College of Wisconsin, Milwaukee, 53226.
AJR Am J Roentgenol. 1987 Dec;149(6):1155-60. doi: 10.2214/ajr.149.6.1155.
The relative efficacies of different spin-echo pulse sequences at 1.5 T were evaluated in the detection of focal hepatic disease. Pulse sequences compared were spin-echo with a repetition time (TR) of 200 msec and echo time (TE) of 20 msec, with six excitations; TR = 300 msec, TE = 20 msec, with 16 excitations (T1-weighted sequences); and a double spin-echo with TR = 2500 and TE = 25 and 70, with two excitations (proton-density-weighted and T2-weighted pulse sequences, respectively). Respiratory-motion compensation, which involved a recording of the phase-encoding gradients (Exorcist), was used for the last two sequences. Spin-echo with TR = 2500 msec and TE = 70 msec was superior in lesion detection and contrast-to-noise ratio. The proton-density-weighted and T2-weighted sequences with respiratory compensation produced better artifact suppression than did the short TR, short TE T1-weighted sequence with temporal averaging. In contradistinction to prior results at 0.6 T, T2-weighted pulse sequences appear superior to T1-weighted pulse sequences with multiple excitations for both lesion detection and artifact suppression at 1.5 T.
在1.5T场强下，对不同自旋回波脉冲序列检测局灶性肝脏疾病的相对效能进行了评估。所比较的脉冲序列包括：重复时间（TR）为200毫秒、回波时间（TE）为20毫秒且有6次激发的自旋回波序列；TR = 300毫秒、TE = 20毫秒且有16次激发的序列（T1加权序列）；以及TR = 2500且TE = 25和70、有2次激发的双自旋回波序列（分别为质子密度加权和T2加权脉冲序列）。后两个序列采用了呼吸运动补偿，即记录相位编码梯度（驱魔师）。TR = 2500毫秒、TE = 70毫秒的自旋回波序列在病变检测和对比噪声比方面表现更优。与采用时间平均的短TR、短TE T1加权序列相比，采用呼吸补偿的质子密度加权和T2加权序列能更好地抑制伪影。与0.6T场强下的先前结果相反，在1.5T场强下，对于病变检测和伪影抑制，T2加权脉冲序列似乎优于多次激发的T1加权脉冲序列。
