A combined analytical solution for chemical exchange saturation transfer and semi-solid magnetization transfer.
A combined analytical solution for chemical exchange saturation transfer and semi-solid magnetization transfer.
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DOI：
10.1002/nbm.3237
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发表时间：
2015-02
影响因子：
2.9
通讯作者：
Bachert, Peter
中科院分区：
文献类型：
--
作者：
Zaiss, Moritz;Zu, Zhongliang;Xu, Junzhong;Schuenke, Patrick;Gochberg, Daniel F.;Gore, John C.;Ladd, Mark E.;Bachert, Peter
关键词：
组织中的非共振射频辐射通过饱和转移过程间接降低了水信号：一方面，存在源自与水交换几ppm共振的内源质子的选择性化学交换饱和转移（CEST）效应;另一方面，存在源自与具有kHz线宽的组织基质相关的不动质子的宽半固体磁化转移（MT）。最近的研究表明，内源性CEST对比度可以强烈地受到MT背景的影响，因此需要进行校正以获得CEST效应的准确估计。在这里，我们表明，一个完整的分析解决方案的基本布洛赫-麦康奈尔方程MT和CEST提供了深入了解他们的相互作用，并提出了一个简单的方法来隔离他们的影响。所提出的解析解，基于本征空间的解决方案的布洛赫-麦康奈尔方程，通过允许任意的半固态MT效应的线形，并同时描述多个CEST池中存在的一个大MT池任意照射，扩展了以前的治疗。该模型的结构表明，半固态MT和CEST效应基本上加起来，在确定稳态Z-谱，如前所示的直接饱和和CEST效应。现有的CEST分析的存在下，半固体MT的影响进行了研究和讨论。事实证明，为了准确地量化CEST对比度，必须知道良好的参考Z值、观察到的水的纵向弛豫速率和半固体MT池尺寸分数。
Off-resonant radiofrequency irradiation in tissue indirectly lowers the water signal by saturation transfer processes: On the one hand, there are selective chemical exchange saturation transfer (CEST) effects originating from exchanging endogenous protons resonating a few ppm from water; on the other hand, there is the broad semi-solid magnetization transfer (MT) originating from immobile protons associated with the tissue matrix with kHz line-widths. Recently it was shown that endogenous CEST contrasts can be strongly affected by the MT background so that corrections are needed to derive accurate estimates of CEST effects. Herein we show that a full analytical solution of the underlying Bloch-McConnell equations for both MT and CEST provides insights into their interaction and suggests a simple means to isolate their effects. The presented analytical solution, based on the eigenspace solution of the Bloch-McConnell equations, extends previous treatments by allowing arbitrary line-shapes for the semi-solid MT effects and simultaneously describing multiple CEST pools in the presence of a large MT pool for arbitrary irradiation. The structure of the model indicates that semi-solid MT and CEST effects basically add up inversely in determining the steady-state Z-spectrum, as previously shown for direct saturation and CEST effects. Implications for existing previous CEST analyses in the presence of a semi-solid MT are studied and discussed. It turns out that to accurately quantify CEST contrast, a good reference Z-value, the observed longitudinal relaxation rate of water, and the semi-solid MT pool size fraction, must all be known.
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影响因子：
3.3
作者：
Desmond, Kimberly L.;Moosvi, Firas;Stanisz, Greg J.
通讯作者：
Stanisz, Greg J.
DOI：
10.1006/jmra.1993.1229
发表时间：
1993-10-01
期刊：
JOURNAL OF MAGNETIC RESONANCE SERIES A
影响因子：
--
作者：
ADLER, RS;YEUNG, HN
通讯作者：
YEUNG, HN
影响因子：
3.3
作者：
Ou, Xiawei;Gochberg, Daniel Frank
通讯作者：
Gochberg, Daniel Frank
影响因子：
5.7
作者：
Jin, Tao;Wang, Ping;Zong, Xiaopeng;Kim, Seong-Gi
通讯作者：
Kim, Seong-Gi
影响因子：
2.9
作者：
Goerke, Steffen;Zaiss, Moritz;Bachert, Peter
通讯作者：
Bachert, Peter