Yongbi N M, Payne G S, Collins D J, Leach M O
CRC Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Sutton, Surrey, UK.
Phys Med Biol. 1995 Jul;40(7):1293-303. doi: 10.1088/0031-9155/40/7/011.
The three most widely used single-volume NMR localization techniques (ISIS, STEAM and PRESS) are assessed quantitatively for 1H spectroscopy using an EEC localization test object. Signal selection efficiency, suppression of outer volume signals and contamination are measured on a 1.5 T whole-body Siemens GBS1 system. The ISIS signal selection efficiency (volume of interest (VOI), 1-125 cm3) ranged from 90% to 95%, with T1 relaxation during the sequence shown to account for the observed 5-10% signal loss. Contamination for ISIS was found to be higher for smaller VOIS and ranged from approximately 45% (VOI = 1 cm3) to approximately 9% (VOI = 125 cm3). For PRESS, contamination ranged from 7% to 12% and it was between 3% and 8% for STEAM. However, the maximum signal selection efficiency for the latter two techniques (echo time, 270 ms) was relatively low (10-17%), and limited by T2 losses and the non-rectangular slice profiles of sinc pulses.
使用一个欧洲经济共同体（EEC）定位测试体模，对1H波谱分析中最广泛使用的三种单容积核磁共振定位技术（ISIS、STEAM和PRESS）进行了定量评估。在一台1.5T全身西门子GBS1系统上测量了信号选择效率、外容积信号抑制和污染情况。ISIS信号选择效率（感兴趣容积（VOI），1 - 125cm³）范围为90%至95%，序列中的T1弛豫被证明是观察到的5% - 10%信号损失的原因。发现对于较小的VOI，ISIS的污染更高，范围从约45%（VOI = 1cm³）到约9%（VOI = 125cm³）。对于PRESS，污染范围为7%至12%，对于STEAM则在3%至8%之间。然而，后两种技术（回波时间，270ms）的最大信号选择效率相对较低（10% - 17%），并受T2损失和sinc脉冲的非矩形切片轮廓限制。
