3T下脑肿瘤中甘氨酸的活体（1）H磁共振波谱成像
In vivo (1)H MRSI of glycine in brain tumors at 3T.
作者信息
Ganji Sandeep K, Maher Elizabeth A, Choi Changho
机构信息
Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
出版信息
Magn Reson Med. 2016 Jan;75(1):52-62. doi: 10.1002/mrm.25588. Epub 2015 Feb 4.
PURPOSE
MR spectroscopic imaging (SI) of glycine (Gly) in the human brain is challenging due to the interference of the abundant neighboring J-coupled resonances. Our aim is to accomplish reliable imaging of Gly in healthy brain and brain tumors using an optimized MR sequence scheme at 3 tesla.
METHODS
Two-dimensional (1)H SI was performed with a point-resolved spectroscopy scheme. An echo time of 160 ms was used for separation between Gly and myo-inositol signals. Data were collected from eight healthy volunteers and 14 subjects with gliomas. Spectra were analyzed with the linear combination model using numerically calculated basis spectra. Metabolite concentrations were estimated with reference to creatine in white matter (WM) regions at 6.4 molar concentrations (mM).
RESULTS
From a linear regression analysis with respect to the fractional gray matter (GM) content, the Gly concentrations in pure GM and WM in healthy brains were estimated to be 1.1 and 0.3 mM, respectively. Gly was significantly elevated in tumors. The tumor-to-contralateral Gly concentration ratio was more extensive with higher grades, showing ∼ 10-fold elevation of Gly in glioblastomas.
CONCLUSION
The Gly level is significantly different between GM and WM in healthy brains. Our data indicate that SI of Gly may provide a biomarker of brain tumor malignancy.
目的
由于丰富的邻近 J 耦合共振的干扰，对人脑中甘氨酸（Gly）进行磁共振波谱成像（SI）具有挑战性。我们的目的是使用 3 特斯拉的优化磁共振序列方案，在健康脑和脑肿瘤中实现对甘氨酸的可靠成像。
方法
采用点分辨波谱方案进行二维（1）H SI。使用 160 毫秒的回波时间来分离甘氨酸和肌醇信号。从 8 名健康志愿者和 14 名患有胶质瘤的受试者收集数据。使用数值计算的基础波谱，通过线性组合模型分析波谱。代谢物浓度以白质（WM）区域中 6.4 摩尔浓度（mM）的肌酸为参照进行估计。
结果
通过对灰质（GM）含量分数的线性回归分析，健康脑中纯 GM 和 WM 中的甘氨酸浓度估计分别为 1.1 和 0.3 mM。肿瘤中的甘氨酸显著升高。肿瘤与对侧的甘氨酸浓度比在更高分级时更为显著，在胶质母细胞瘤中甘氨酸升高约 10 倍。
结论
健康脑中 GM 和 WM 之间的甘氨酸水平存在显著差异。我们的数据表明，甘氨酸的 SI 可能提供脑肿瘤恶性程度的生物标志物。
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