Ryner L N, Ke Y, Thomas M A
Institute for Biodiagnostics, National Research Council, Winnipeg, Manitoba, Canada.
J Magn Reson. 1998 Mar;131(1):118-25. doi: 10.1006/jmre.1997.1333.
Flip angle dependence of the localized single-voxel 1H NMR spectroscopic sequences STEAM and PRESS using numerically optimized Shinnar-Le Roux (SLR) and conventional sinc RF pulses has been evaluated. Phantom experiments were used to evaluate voxel profiles from MR images of the selected voxels. Information on the total excited volume was recorded from the integrated area under the water peak in the localized spectrum at different flip angles (theta = 0 degrees-180 degrees). The voxel profiles for both the STEAM and PRESS sequences using the SLR RF pulses were found to be identical, unlike the case for the sinc RF pulses. The SLR RF pulses in the PRESS sequence were found to be more sensitive to flip angle variations. Localized, water-suppressed 1H NMR spectra recorded from the frontal gray matter in healthy volunteers (n = 3) showed less lipid contamination using the SLR RF pulses compared with the sinc RF pulses.
已评估了使用数值优化的辛纳-勒鲁（SLR）和传统 sinc 射频脉冲的局部单体素 1H 核磁共振波谱序列 STEAM 和 PRESS 的翻转角依赖性。使用体模实验从所选体素的磁共振图像评估体素轮廓。在不同翻转角（θ = 0 度 - 180 度）下，从局部谱中水峰下的积分面积记录有关总激发体积的信息。发现使用 SLR 射频脉冲时，STEAM 和 PRESS 序列的体素轮廓相同，这与使用 sinc 射频脉冲的情况不同。发现 PRESS 序列中的 SLR 射频脉冲对翻转角变化更敏感。与 sinc 射频脉冲相比，使用 SLR 射频脉冲从健康志愿者（n = 3）的额叶灰质记录的局部水抑制 1H 核磁共振波谱显示脂质污染更少。
