Hancu I, van der Maarel J R, Boada F E
Department of Physics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
J Magn Reson. 2000 Dec;147(2):179-91. doi: 10.1006/jmre.2000.2177.
We have derived the differential equations that describe the dynamics of spin-3/2 nuclei in the presence of radiofrequency (RF) fields and both static and fluctuating quadrupolar interactions. The formalism presented was used to predict the sodium triple-quantum-filtered (TQ-filtered) signal loss in a whole-body scanner, where the widths of the hard 90 degrees RF pulses are on the same order of magnitude as the transverse relaxation times. A small piece of bovine nasal cartilage, known for exhibiting residual quadrupolar splittings, was used to test the theory. The sample was modeled as consisting of small domains, each characterized by a static quadrupolar interaction constant, with an overall Gaussian distribution across the sample. An increase of about 15% in the TQ-filtered signal strength, as the 90 degrees RF pulse width was decreased from 500 to 100 micros, was predicted and demonstrated experimentally for this particular sample.
我们推导了描述自旋3/2原子核在存在射频（RF）场以及静态和波动四极相互作用情况下动力学的微分方程。所提出的形式体系被用于预测全身扫描仪中钠三量子滤波（TQ滤波）信号损失，其中硬90度RF脉冲的宽度与横向弛豫时间处于同一数量级。一小片以呈现残余四极分裂而闻名的牛鼻软骨被用于检验该理论。该样品被建模为由小区域组成，每个区域由一个静态四极相互作用常数表征，且在整个样品上呈总体高斯分布。对于这个特定样品，预测并通过实验证明，当90度RF脉冲宽度从500微秒减小到100微秒时，TQ滤波信号强度增加了约15%。
