Igarashi Hironaka, Ueki Satoshi, Ohno Ken, Ohkubo Masaki, Suzuki Yuji
Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata.
Radiological Technology, School of Health Science Faculty of Medicine, University of Niigata.
J Nippon Med Sch. 2017;84(4):160-164. doi: 10.1272/jnms.84.160.
Molecular imaging implies the method capable of pictorially displaying distribution of target molecules and their relative concentration in space. In clinical medicine, where non-invasiveness is mandatory, diagnostic molecular imaging has been considered virtually identical to positron emission tomography (PET). However, there is another powerful, apparently underutilized molecular imaging, namely, proton magnetic resonance spectroscopic imaging (H-MRSI). The technique can detect target molecules endogenous in brain in virtue of their own specific resonance frequencies (chemical shift) and can create quantitative images of each molecule. H-MRSI is conventionally utilized for imaging relatively easily detectable molecules such as N-acetyl-aspartate or lactate. More recently, however, the method is extended into imaging of more challenging molecules such as glutamate or γ-aminobutyric acid (GABA). In this small review, we summarize basic concept of H-MRSI and introduce an advanced technique, i.e. chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), which made realistic glutamate imaging in vivo possible.
分子成像指的是能够以图像形式显示目标分子的分布及其在空间中的相对浓度的方法。在临床医学中，非侵入性是必不可少的，诊断性分子成像实际上一直被认为等同于正电子发射断层扫描（PET）。然而，还有另一种强大的、显然未得到充分利用的分子成像技术，即质子磁共振波谱成像（H-MRSI）。该技术能够凭借脑内源性目标分子自身特定的共振频率（化学位移）来检测它们，并能生成每个分子的定量图像。传统上，H-MRSI用于对相对容易检测的分子成像，如N-乙酰天门冬氨酸或乳酸。然而，最近该方法已扩展到对更具挑战性的分子成像，如谷氨酸或γ-氨基丁酸（GABA）。在这篇简短的综述中，我们总结了H-MRSI的基本概念，并介绍了一种先进技术，即化学交换饱和转移磁共振成像（CEST MRI），它使体内谷氨酸的实际成像成为可能。
