Average saturation efficiency filter (ASEF) for CEST imaging.
Average saturation efficiency filter (ASEF) for CEST imaging.
复制标题
用于CEST成像的平均饱和效率滤波器（ASEF）。
DOI：
10.1002/mrm.29211
复制
发表时间：
2022-07
影响因子：
3.3
通讯作者：
Chung, Julius Juhyun
中科院分区：
文献类型：
--
作者：
Jin, Tao;Chung, Julius Juhyun
内源性CEST信号通常具有低特异性，这是由于来自磁化转移（MT）效应和来自具有接近拉莫尔频率的快速交换不稳定质子的污染。我们建议用平均饱和效率滤波器（ASEF）来提高CEST信号的特异性。ASEF测量用相似的平均辐射功率但很大程度上不同的占空比（DC）获取的CEST信号之间的差异，例如，连续波或高DC脉冲串与低DC脉冲串。通过模拟实验和肌酸体模实验，对CEST的ASEF特性进行了评价。理论和模拟研究表明，ASEF可以抑制快速交换过程，只有一个小的损失的化学交换对比度缓慢到中等交换速率，如果在DC的差异是大的。在平均饱和功率为0.8和1.6 μT的2至5 ppm RF偏移范围内，CW饱和与DC = 15%和脉冲持续时间为24 ms的脉冲序列之间的MT信号存在约0.1%至2%的失配。这种不匹配可以通过仔细选择饱和功率、脉冲持续时间和DC差异或通过在两个照射功率之间应用小的模糊因子来最小化。肌酸的体模研究证实，ASEF可以最大限度地减少MT效应，降低对快速交换过程的敏感性。ASEF可提高慢至中等交换CEST信号的特异性，而敏感性损失相对较小。
Endogenous CEST signal usually has low specificity due to contamination from the magnetization transfer (MT) effect and from fast exchanging labile protons with close Larmor frequencies. We propose to improve CEST signal specificity with an Average Saturation Efficiency Filter (ASEF). ASEF measures the difference between CEST signals acquired with similar average irradiation power but largely different duty cycles (DC), e.g., a continuous wave or a high DC pulse train versus a low DC one. Simulation and creatine phantom studies were performed to evaluate the characteristics of ASEF for CEST. Theoretical and simulation studies show that ASEF can suppress fast exchanging processes, with only a small loss of chemical exchange contrast for slow to intermediate exchange rates if the difference in DC is large. In the RF offset range of 2 to 5 ppm with an averaged saturation power of 0.8 and 1.6 μT, there is a mismatch of ~0.1% to 2% in the MT signal between saturation by CW and a pulse train with DC = 15% and pulse duration of 24 ms, respectively. This mismatch can be minimized by careful selection of saturation power, pulse duration, and DC differences or by applying a small fudge factor between the two irradiation powers. Phantom studies of creatine confirmed that ASEF can minimize the MT effect and reduce sensitivity to fast exchange processes. ASEF can improve the specificity of slow to intermediate exchanging CEST signal with a relatively small loss of sensitivity.
登录
查看更多内容
来自Z频谱拟合的2ppm（CEST@2ppm）处的CEST信号与脑肿瘤中的肌酸分布相关。
影响因子：
2.9
作者：
Cai, Kejia;Singh, Anup;Poptani, Harish;Li, Weiguo;Yang, Shaolin;Lu, Yang;Hariharan, Hari;Zhou, Xiaohong J.;Reddy, Ravinder
通讯作者：
Reddy, Ravinder
影响因子：
3.3
作者：
Desmond, Kimberly L.;Moosvi, Firas;Stanisz, Greg J.
通讯作者：
Stanisz, Greg J.
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：
15
作者：
Friedman, Joshua I.;McMahon, Michael T.;Stivers, James T.;Van Zijl, Peter C. M.
通讯作者：
Van Zijl, Peter C. M.
影响因子：
2.9
作者：
Goerke, Steffen;Zaiss, Moritz;Bachert, Peter
通讯作者：
Bachert, Peter