Longo R, Vidimari R
Istituto di Radiologia, Università degli Studi de Trieste, Ospedale di Cattinara, Italy.
Phys Med Biol. 1994 Jan;39(1):207-15. doi: 10.1088/0031-9155/39/1/013.
The aim of this study was the experimental characterization of the PRESS technique for image-guided in vivo 1H NMR spectroscopy, as implemented on a commercially available 1.5 T NMR whole-body system. Three characterization parameters were defined and evaluated in test object measurements: selection efficiency, suppression efficiency and contamination. The characterization parameters were evaluated in different experimental conditions. The profile of signal intensity across the volume of interest (VOI) was investigated. Our results show that the characterization parameters are slightly affected by the echo time, while they are not affected by changes in the repetition time. When the VOI is co-extensive with the inner cube of the test object the suppression efficiency is good but the selection efficiency is not very high. Contamination is affected by the synthesizer frequency offset, while the selection efficiency is quite stable. Contamination effects become significant in case of 90 degrees pulse maladjustment.
本研究的目的是对用于图像引导的体内1H NMR光谱的PRESS技术进行实验表征，该技术在市售的1.5 T NMR全身系统上实现。在测试对象测量中定义并评估了三个表征参数：选择效率、抑制效率和污染。在不同的实验条件下对表征参数进行了评估。研究了感兴趣体积（VOI）内的信号强度分布。我们的结果表明，表征参数受回波时间的影响较小，而不受重复时间变化的影响。当VOI与测试对象的内立方体共扩展时，抑制效率良好，但选择效率不是很高。污染受合成器频率偏移的影响，而选择效率相当稳定。在90度脉冲失调的情况下，污染效应变得显著。
