MT effects and T1 quantification in single-slice spoiled gradient echo imaging
MT effects and T1 quantification in single-slice spoiled gradient echo imaging
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DOI：
10.1002/mrm.21550
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发表时间：
2008-04-01
影响因子：
3.3
通讯作者：
Gochberg, Daniel Frank
中科院分区：
文献类型：
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作者：
Ou, Xiawei;Gochberg, Daniel Frank
我们研究了磁化转移（MT）对受到一系列相同的共振RF脉冲的样本的稳态MR信号的影响，例如在使用受扰梯度回波序列对单个切片进行成像时会遇到的影响。在Bloch方程中加入MT耦合项，导出了稳态信号方程，并与不考虑MT效应的常规信号方程进行了比较。由于MT，稳态信号增加了平衡磁化的百分之几。这种MT效应的一个后果是通过常规稳态梯度回波方法确定的T-1值不准确。（当使用短TR时，理论预测白色物质的T-1误差大于10%。）第二个结果是通过将梯度回波稳态信号拟合到适当修改以包括MT效应的信号方程来量化弛豫和MT参数的能力。在MnCl 2、交联牛血清白蛋白（BSA）和交联BSA + MnCl 2样品中测试了该理论。
We investigated magnetization transfer (MT) effects on the steady-state MR signal for a sample subjected to a series of identical on-resonance RF pulses, such as would be experienced while imaging a single slice using a spoiled gradient echo sequence. The MT coupling terms for a two-pool system were added to the Bloch equations and we derived the resulting steady-state signal equation and compared this result to the conventional signal equation without MT effects. The steady-state signal is increased by a few percent of the equilibrium magnetization because of MT. One consequence of this MT effect is inaccuracy in T-1 values determined via conventional steady-state gradient echo methods. (Theory predicts greater than 10% errors in T-1 for white matter when using short TR.) A second consequence is the ability to quantify the relaxation and MT parameters by fitting the gradient echo steady state signal to the signal equation appropriately modified to include MT effects. The theory was tested in samples of MnCl2, crosslinked bovine serum albumin (BSA), and cross-linked BSA + MnCl2.