University of Pennsylvania, Radiology, Philadelphia, PA, USA.
NMR Biomed. 2013 Oct;26(10):1278-84. doi: 10.1002/nbm.2949. Epub 2013 Apr 3.
In vivo measurement of glutamate (Glu) in brain subcortex can elucidate the role these structures play in cognition and neuropsychiatric disorders. However, accurate quantification of Glu in subcortical regions is challenging. Recently, a novel MRI method based on the Glu chemical exchange saturation transfer (GluCEST) effect has been developed for detecting brain Glu in millimolar concentrations. Here, we use GluCEST to map Glu distributions in subcortical structures of the human brain (e.g. amygdala, hippocampus). Overall, GluCEST was 40% higher in gray matter than in white matter. Within the subcortical gray matters, amygdala showed the highest GluCEST contrast. Utilizing MR spectroscopic data, in vivo GluCEST detection sensitivity (0.8% mM(-1) ) in subcortical gray matter was evaluated and was consistent with the previously reported values. In general, the GluCEST map approximates the Glu receptor distribution reported in previous positron emission tomography (PET) studies. These findings suggest that high-resolution GluCEST MRI of subcortical brain structures may prove to be a useful tool in diagnosis of brain disorders or treatment responses.
在体测量脑皮质下谷氨酸（Glu）可以阐明这些结构在认知和神经精神疾病中的作用。然而，准确测量皮质下区域的 Glu 是具有挑战性的。最近，一种基于 Glu 化学交换饱和转移（GluCEST）效应的新型 MRI 方法已经被开发出来，用于检测毫摩尔浓度的脑 Glu。在这里，我们使用 GluCEST 来绘制人类大脑皮质下结构（如杏仁核、海马体）中的 Glu 分布。总的来说，灰质中的 GluCEST 比白质高约 40%。在皮质下灰质中，杏仁核显示出最高的 GluCEST 对比。利用磁共振波谱数据，评估了皮质下灰质中 GluCEST 的体内检测灵敏度（约为 0.8% mM(-1)），与之前报道的值一致。一般来说，GluCEST 图谱与之前正电子发射断层扫描（PET）研究中报道的 Glu 受体分布情况相近。这些发现表明，皮质下脑结构的高分辨率 GluCEST MRI 可能成为诊断脑疾病或治疗反应的有用工具。
