Mapping of Amide, Amine, and Aliphatic Peaks in the CEST Spectra of Murine Xenografts at 7 T
Mapping of Amide, Amine, and Aliphatic Peaks in the CEST Spectra of Murine Xenografts at 7 T
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DOI：
10.1002/mrm.24822
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发表时间：
2014-05-01
影响因子：
3.3
通讯作者：
Stanisz, Greg J.
中科院分区：
文献类型：
--
作者：
Desmond, Kimberly L.;Moosvi, Firas;Stanisz, Greg J.
目的评估肿瘤异种移植纵向研究中内源性化学交换饱和转移（CEST）光谱和衍生图的性能，以确定CEST参数在描述肿瘤进展以及区分肿瘤、肌肉和坏死方面的作用。方法在三个时间点采集24只肿瘤异种移植小鼠（20只LLC和4只MDA）的CEST光谱。我们采用了一种新的方法分解CEST频谱的总和的四个洛伦兹形状，每个具有相应的测量振幅，宽度和频率偏移。这种半定量方法是对简单评估CEST存在的光谱不对称性的技术的改进，因为它不会被直接效应相对侧的CEST峰混淆。CEST图像进行了比较，其他几个常用的对比机制：T-1弛豫，T-2弛豫，扩散（ADC），和磁化传递（MT）。结果肿瘤光谱有明显的CEST峰对应的存在下，自由水和酰胺，胺，和脂肪族基团之间的氢交换。所有三个CEST峰（酰胺，胺，和脂肪族）在肿瘤组织中较大，与邻近的健康muscle.ConclusionsCEST对比（特别是胺峰振幅）执行特别好，在区分区域的细胞凋亡和/或坏死积极进展的肿瘤，组织学验证。Magn Reson Med 71：1841-1853，2014年。(c)2013 Wiley Periodicals，Inc.
PurposeTo evaluate the performance of endogenous chemical exchange saturation transfer (CEST) spectra and derived maps in a longitudinal study of tumor xenografts to ascertain the role of CEST parameters in describing tumor progression and in distinguishing between tumor, muscle, and necrosis.MethodsCEST spectra of 24 mice with tumor xenografts (20 LLC and 4 MDA) were acquired at three time-points. We employed a novel method of decomposing the CEST spectrum into a sum of four Lorentzian shapes, each with a corresponding measured amplitude, width and frequency offset. This semi-quantitative method is an improvement over techniques which simply assess the asymmetry in the spectrum for the presence of CEST, due to the fact that it is not confounded by CEST peaks on opposing sides of the direct effect. The CEST images were compared to several other commonly employed contrast mechanisms: T-1 relaxation, T-2 relaxation, diffusion (ADC), and magnetization transfer (MT).ResultsTumor spectra had distinct CEST peaks corresponding to the presence of hydrogen exchange between free water and amide, amine, and aliphatic groups. All three CEST peaks (amide, amine, and aliphatic) were larger in the tumor tissue as compared with the adjacent healthy muscle.ConclusionsCEST contrast (particularly the amine peak amplitude) performed especially well in distinguishing areas of apoptosis and/or necrosis from actively progressing tumor, as validated by histology. Magn Reson Med 71:1841-1853, 2014. (c) 2013 Wiley Periodicals, Inc.