Development of absolute quantitation method in metabolites in human brain in vivo using high magnetic field MRI

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K08040
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: National Institute for Environmental Studies
• Principal Investigator: Watanabe Hidehiro 国立研究開発法人国立環境研究所, 環境リスク・健康領域, 領域長 (60370269)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: ヒト脳 / 代謝物 / 高磁場MRI / グルタミン酸 / GABA / グルタミン / 濃度定量化 / 1H MRS

Outline of Final Research Achievements

1H magnetic resonance spectroscopy (1H MRS) can enable us to measure metabolites in the human brain noninvasively. By using high magnetic field MRI, 1H spectra with features of high sensitivity and high peak resolution. However, the inhomogeneous distribution of the high-frequency magnetic field makes it difficult to quantify the concentration of metabolites. To overcome this problem, we proposed and developed a method to acquire the reception sensitivity ratio between the concentration reference phantom and the human brain using a homogeneous region and implemented it in a 4.7T MRI for humans. After confirming the performance through phantom experiments, measurements were performed on human brain. As a result, metabolites such as N-acetyl aspartate, creatine, glutamic acid, and aspartic acid, which are metabolites of human brain, could be quantified in concentration.

Free Research Field

磁気共鳴工学

Academic Significance and Societal Importance of the Research Achievements

非侵襲測定が可能なMRIは、臨床に不可欠な診断装置となっている。ヒト脳の画像で良好なコントラストが得られることが良く知られている一方で、疾患との関連性が示唆され、医学的有用性が期待されるヒト脳内の代謝物測定では、高感度化、高分解能化が期待出来る高磁場MRIでの開発が進められているものの、濃度定量化が難しいという問題があった。本研究では、この問題を克服するための方法を提案、開発し、試薬実験による性能の確認を行った。これに続いて、ヒト脳での1Hスペクトル測定、濃度定量化を実施し、ヒト脳内のNアセチルアスパラギン酸、グルタミン酸などの代謝物の濃度を求めることが出来た。