In vivo three-dimensional whole-brain pulsed steady-state chemical exchange saturation transfer at 7 T.
In vivo three-dimensional whole-brain pulsed steady-state chemical exchange saturation transfer at 7 T.
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DOI：
10.1002/mrm.23141
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发表时间：
2012-06
影响因子：
3.3
通讯作者：
van Zijl, Peter C. M.
中科院分区：
文献类型：
--
作者：
Jones, Craig K.;Polders, Daniel;Hua, Jun;Zhu, He;Hoogduin, Hans J.;Zhou, Jinyuan;Luijten, Peter;van Zijl, Peter C. M.
关键词：
化学交换饱和转移（CEST）是一种通过水信号间接检测可交换质子的技术，以增加其对人类研究的适用性，需要开发敏感的脉冲序列，以快速增强整个器官图像占空比的限制和SAR限制。 （MTC）使CEST定量变得复杂，需要尽可能减少。通过使用有限的B1强度的3D稳态脉冲采集（〜1μT）。 B1，而这种质子的CEST效应的大小最少取决于B1（65 ms）的稳态序列，该稳态序列由短暂的饱和脉冲（25 ms）组成大约在每个满意度频率的大约11 s，而在SAR范围内保持良好状态，MTC大大降低了，但在水的频率上发现了实质性的安全效应仍然可以探索MT不对称分析的使用，可以探索DS信号的有限宽度，以使用Lorentzian函数拟合，允许CEST定量效果和时间效率的3D脉冲CEST采集方案应在高场和低场上有助于内源性CEST定量。
Chemical exchange saturation transfer (CEST) is a technique to indirectly detect pools of exchangeable protons through the water signal. To increase its applicability to human studies, it is needed to develop sensitive pulse sequences for rapidly acquiring whole-organ images while adhering to stringent amplifier duty cycle limitations and SAR restrictions. In addition, the interfering effects of direct water saturation (DS) and conventional magnetization transfer contrast (MTC) complicate CEST quantification and need to be reduced as much as possible. It is shown that for protons exchanging with rates of less than 50–100 Hz, such as imaged in amide proton transfer (APT) experiments, these problems can be addressed by using a 3D steady state pulsed acquisition of limited B1 strength (~1 μT). Such an approach exploits the fact that the DS width, MTC magnitude, and SAR increase strongly with B1, while the size of the CEST effect for such protons depends minimally on B1. A short-TR (65 ms) steady state sequence consisting of a brief saturation pulse (25 ms) and a segmented EPI train allowed acquisition of a 3D whole-brain volume in approximately 11 s per saturation frequency, while remaining well within SAR and duty cycle limits. MTC was strongly reduced, but substantial saturation effects were found at frequencies upfield from water, which still confound the use of MT asymmetry analysis. Fortunately, the limited width of the DS signal could be exploited to fit it with a Lorentzian function allowing CEST quantification. APT effects ranged between 1.5 and 2.5% in selected white and gray matter regions. This power and time-efficient 3D pulsed CEST acquisition scheme should aid endogenous CEST quantification at both high and low field.
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CEST-FISP：一种在7 t处的快速化学交换饱和转移MRI的新技术。
影响因子：
3.3
作者：
Shah, T.;Lu, L.;Dell, K. M.;Pagel, M. D.;Griswold, M. A.;Flask, C. A.
通讯作者：
Flask, C. A.
影响因子：
3.3
作者：
Liu, Guanshu;Li, Yuguo;Pagel, Mark D.
通讯作者：
Pagel, Mark D.
影响因子：
2.7
作者：
Hwang, TL;van Zijl, PCM;Mori, S
通讯作者：
Mori, S
影响因子：
3.3
作者：
Kim M;Gillen J;Landman BA;Zhou J;van Zijl PC
通讯作者：
van Zijl PC
影响因子：
3.3
作者：
Mori, S;Eleff, SM;van Zijl, PCM
通讯作者：
van Zijl, PCM