Clinical application of extracellular pH mapping as new quantitative biomarker

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K16759
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: The University of Tokushima
• Principal Investigator: MATSUMOTO Yuki 徳島大学, 大学院医歯薬学研究部(医学域), 助教 (70838151)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: MRI / QPM / 造影剤 / 細胞外ｐH / pHe

Outline of Final Research Achievements

We present a new method to evaluate relaxivity (r1) and contrast agent concentration separately in contrast-enhanced lesions using quantitative parameter mapping (QPM). Furthermore, we also aimed to estimate the extracellular pH (pHe) of tumor lesions. We demonstrated that it is possible to evaluate pathophysiological tumor changes due to therapeutic efficacy by measuring r1 in contrast-enhanced lesions. In this study, the primary brain tumor group showed significantly higher r1 values than other brain disease groups. Moreover, mean pHe value showed a trend for tumor malignancy having a lower pHe value and primary brain tumor having a significantly lower pHe than other brain diseases. Our results might suggest that QPM can separately quantify r1 and CA concentration in brain tumors and that pHe brain tumor mapping could serve as a tumor biomarker. In conclusion, our method has potential clinical applications for assessing the treatment effects.

Free Research Field

放射線医学

Academic Significance and Societal Importance of the Research Achievements

脳腫瘍の代謝変化を評価することは，正確な診断において重要である．今日の臨床診断では，MRI装置を用いた造影剤検査が多く用いられる．しかし，これは相対的なMR信号変化であり，脳腫瘍の代謝変化を定量評価することは難しい．この問題を解決するため，研究代表者はquantitative parameter mapping（QPM）技術を用いた細胞外pHマッピングを開発し，脳腫瘍代謝変化の定量マッピングを試みている．細胞外pHを正確に測定すること（細胞外pHマッピング）は，腫瘍の進行度を正確に診断するための重要な手段になりうる.