Development of a novel diffusion magnetic resonance imaging for detecting cerebral interstitial fluid flow and investigation of human glymphatic system

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K12767
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 90110:Biomedical engineering-related
• Research Institution: Fujita Health University
• Principal Investigator: Umezawa Eizou 藤田医科大学, 保健学研究科, 准教授 (50318359)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: MRI / 拡散 / グリンパティック / neurofluid / diffusion MRI / glymphatic / machine learning / self-supervised

Outline of Final Research Achievements

It has been pointed out that the brain, where the lymphatic system does not exist, may have a glymphatic system instead. We have developed a method to detect the movement of the cerebral interstitial fluid, a component of the glymphatic system, using MRI. It has been said that the intensity of diffusion-weighted MR images is not affected by the coherent movement of water molecules, but we found that the coherent component also affects the intensity of diffusion-weighted images when the coherent and incoherent components are mixed. Using this fact, we developed a method to detect the nature of coherent movement. We revealed some of the characteristics of cerebral interstitial fluid movement with this method. It was suggested that cerebral interstitial fluid tends to flow in the direction of gravity.

Free Research Field

物理学

Academic Significance and Societal Importance of the Research Achievements

拡散強調 MR 画像（DWI）は広く臨床で使われている。水分子の方向が揃った（coherent な）動きは DWI の位相には影響するが強度には影響しないと言われてきた。本研究では coherent・incoherent 成分が混在する場合には coherent 成分も DWI 強度に影響することを明らかにした。これはこれまで見過ごされてきた事実でありそれに基ずく新しい技術や解析法が今後開発されうる。また、脳間質液は重力方向に流れる傾向があることが示唆された。これはグリンパティック系による脳の老廃物の除去のメカニズムの解明につながる発見であり、今後アルツハイマー型認知症の治療などに貢献しうる。