de Graaf R A, Luo Y, Terpstra M, Garwood M
Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis 55455, USA.
J Magn Reson B. 1995 Nov;109(2):184-93. doi: 10.1006/jmrb.1995.0008.
Amplitude- and frequency-modulated pulses, known as adiabatic pulses, can induce uniform flip angles in the presence of extreme B1 inhomogeneity, which makes them advantageous for in vivo surface-coil studies. This paper describes the conversion of conventional (square pulse-based) spectral-editing sequences into their adiabatic counterparts. Eight adiabatic homo- and heteronuclear sequences are experimentally evaluated for lactate editing. For homonuclear lactate editing, gradient-enhanced multiple-quantum-coherence filtering provides the best overall performance (100% signal recovery with excellent water and lipid suppression in a single acquisition). For heteronuclear [3-(13)C]lactate editing, gradient-enhanced heteronuclear multiple-quantum-coherence filtering provides the best suppression of unwanted signals in a single acquisition, whereas J-modulated spin-echo sequences yield maximum sensitivity.
幅度和频率调制脉冲,即绝热脉冲,在存在极端B1不均匀性的情况下可诱导均匀的翻转角,这使其有利于体内表面线圈研究。本文描述了将传统的(基于方波脉冲的)频谱编辑序列转换为其绝热对应序列。对八个绝热同核和异核序列进行了乳酸编辑的实验评估。对于同核乳酸编辑,梯度增强多量子相干滤波提供了最佳的整体性能(在单次采集中实现100%的信号恢复,并具有出色的水和脂质抑制效果)。对于异核[3-(13)C]乳酸编辑,梯度增强异核多量子相干滤波在单次采集中提供了对不需要信号的最佳抑制,而J调制自旋回波序列产生最大灵敏度。