Development of in vivo cortical segmental mapping using 7 tesla ultra-high field MRI

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22985
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 90:Biomedical engineering and related fields
• Research Institution: National Institute for Physiological Sciences
• Principal Investigator: Fukunaga Masaki 生理学研究所, システム脳科学研究領域, 准教授 (40330047)
• Co-Investigator(Kenkyū-buntansha): 梅田 雅宏 明治国際医療大学, 医学教育研究センター, 教授 (60223608)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: ７テスラMRI / 髄鞘密度 / 大脳皮質 / 高分解能MRI / 磁化率

Outline of Final Research Achievements

The development of a multi-echo gradient echo for deriving quantitative magnetic susceptibility and T2*-relaxation time images specialized for microstructure　in the cortex, and the development of an imaging technique for separately delineating paramagnetic and diamagnetic magnetic susceptibilities required to separate and identify myelin and iron in tissues. The proposed method significantly reduces the artifacts by maintaining the readout gradient scheme between echoes in the mirroring/balanced relationship. In the latter, a model separating paramagnetic and diamagnetic susceptibilities was generated from the frequency shift and R2' relaxation time, enabling the acquisition of diamagnetic susceptibility images highly consistent with intraparenchymal myelin distributions obtained from stained images of tissue specimens.

Free Research Field

磁気共鳴医学

Academic Significance and Societal Importance of the Research Achievements

従来の脳画像は、脳の大局的な形状（脳回や脳溝形状、体積や厚さなど）から異常を見出すことを目的とされてきた。しかし、脳の機能局在を示す脳領野は、大脳皮質のメゾスコピックな微細構造形状に基づくため、これらの描出技術が望まれる。本研究では、ヒト生体に応用可能な磁気共鳴法を用いて脳内の微細構造描出技術を開発した。本成果は、脳研究の発展のみならず、神経疾患の病態メカニズム探索にも応用可能と考えられる。