The central signal singularity phenomenon in balanced SSFP and its application to positive-contrast imaging.
The central signal singularity phenomenon in balanced SSFP and its application to positive-contrast imaging.
复制标题
平衡SSFP中的中心信号奇点现象及其在正对比成像中的应用。
DOI：
10.1002/mrm.23156
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发表时间：
2012
影响因子：
3.3
通讯作者：
Nishimura,DwightG
中科院分区：
文献类型：
--
作者：
Ingle,RReeve;Cukur,Tolga;Nishimura,DwightG
稳态序列参数的小扰动可以引起非常大的光谱轮廓偏差，这些偏差局限于特定的非共振频率，表示为临界频率。虽然，少数研究先前已考虑使用这些高度特异性的调制MR血管造影和弹性成像，许多潜在的应用仍然有待探索。使用线性系统技术和几何磁化轨迹技术对这种现象进行的分析表明，临界频率对应于稳态信号方程中的奇点。交错采集结合复数差分技术产生包含与宽阻带交错的尖峰的光谱轮廓，而复数和技术产生类似于平衡稳态自由进动的光谱轮廓。模拟和体模实验用于证明该技术用于超顺磁性氧化铁纳米颗粒的正对比度成像的新应用。该技术被证明产生高水平的正对比度和良好的水和脂肪背景抑制的图像。该技术还可以同时产生具有类似于平衡稳态自由进动的对比度的图像。Magn Reson Med，2011年。© 2011 Wiley Periodicals，Inc.
Small perturbations of steady‐state sequence parameters can induce very large spectral profile deviations that are localized to specific off‐resonant frequencies, denoted critical frequencies. Although, a small number of studies have previously considered the use of these highly specific modulations for MR angiography and elastography, many potential applications still remain to be explored. An analysis of this phenomenon using a linear systems technique and a geometric magnetization trajectory technique shows that the critical frequencies correspond to singularities in the steady‐state signal equation. An interleaved acquisition combined with a complex difference technique yields a spectral profile containing sharp peaks interleaved with wide stopbands, while a complex sum technique yields a spectral profile similar to that of balanced steady‐state free precession. Simulations and phantom experiments are used to demonstrate a novel application of this technique for positive‐contrast imaging of superparamagnetic iron‐oxide nanoparticles. The technique is shown to yield images with high levels of positive contrast and good water and fat background suppression. The technique can also simultaneously yield images with contrast similar to balanced steady‐state free precession. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.