Estimation of the sub-cellular diffusion using multi-exponential fitting model

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K11674
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Pathobiological dentistry/Dental radiology
• Research Institution: Nagasaki University
• Principal Investigator: SASAKI Miho 長崎大学, 病院(歯学系), 助教 (10437874)
• Co-Investigator(Kenkyū-buntansha): 佛坂 由可 長崎大学, 病院(歯学系), 講師 (10244089) ; 中村 卓 長崎大学, 医歯薬学総合研究科(歯学系), 客員研究員 (30172406) ; 高木 幸則 長崎大学, 医歯薬学総合研究科(歯学系), 助教 (30295084) ; 片山 郁夫 長崎大学, 医歯薬学総合研究科(歯学系), 助教 (80295089) ; 榮田 智 長崎大学, 医歯薬学総合研究科(歯学系), 助教 (80325662) ; 角 美佐 長崎大学, 医歯薬学総合研究科(歯学系), 教授 (90284702)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 拡散強調MRI / 細胞内拡散 / 制限拡散

Outline of Final Research Achievements

The aim of this study was to establish the theoretical model for the assessment of restricted diffusion using extremely high b-value diffusion-weighted MRI and reveal the sub-cellular water diffusivity distinguishing from extracellular water. We performed diffusion-weighted MRI of the cell block and cellular-components (nucleus, plasma membrane, organelle membrane, chromatin and DNA) and calculated the diffusion coefficients using multi-exponential curve fitting algorithms. As a result, sub-cellular diffusions were divided into three compartments, suggesting the diffusivities of cytosol, plasma/organelle membranes and intra-nuclear structures. Therefore, we have shown the potential of diffusion-weighted MR imaging with extremely high b-values for estimating subcellular water diffusivity, which could provide the useful information for the various biological process in the cell, including intracellular transport, protein-DNA/RNA interactions, cell division and cell death processes.

Free Research Field

歯科放射線学

Academic Significance and Societal Importance of the Research Achievements

本研究を臨床応用し、生体組織や各種疾患・病変の細胞内の水分子の拡散を細胞外のそれと区別して評価し、その特徴や病変ごとの違いなどを明らかにする事ができれば、拡散現象を通して細胞増殖や細胞死、さらには癌化などといった多様な生命現象に伴う核や細胞内小器官の変化を2次元/3次元的に捉える事が可能で、更に病期の診断や治療効果判定に有用なデータを非侵襲的に提供できると考えられ、学術的・社会的意義は大きい。