-Review-

Magnetic Resonance Imaging of Neurotransmitter-Related Molecules

Hironaka Igarashi¹, Satoshi Ueki¹, Ken Ohno¹, Masaki Ohkubo² and Yuji Suzuki¹

¹Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
²Radiological Technology, School of Health Science Faculty of Medicine, University of Niigata, Niigata, Japan

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 (¹H-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. ¹H-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 ¹H-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.

J Nippon Med Sch 2017; 84: 160-164

Keywords
Brain, MRI, MRS, glutamate, GABA

Correspondence to
Hironaka Igarashi, Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi-dori, Chuo-ku, Niigata City, 951-8585, Japan
higara@bri.niigata-u.ac.jp

Received, May 24, 2017
Accepted, June 16, 2017