| 研究課題/領域番号 |
18F18114
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| 研究機関 | 北海道大学 |
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研究代表者 |
松元 慎吾 北海道大学, 情報科学研究院, 准教授 (90741041)
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| 研究分担者 |
STEWART NEIL 北海道大学, 情報科学研究科, 外国人特別研究員
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| 研究期間 (年度) |
2018-07-25 – 2020-03-31
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| キーワード | MRI / 核偏極 / 代謝 / 分子イメージング |
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| 研究実績の概要 |
Hyperpolarization is a means to obtain ~10000-fold signal enhancement in MRI, enabling visualization of otherwise undetectable biological compounds. Recently-developed side-arm (SA) para-hydrogen induced polarization (PHIP) presents a cost-effective method for producing hyperpolarized 13C for in vivo metabolic MRI. Our research goals are: (i) validate 13C-pyruvate polarized by SA-PHIP as an in vivo metabolic probe in small-animal disease models; (ii) expand the current suite of 13C probes that can be polarized by PHIP for metabolic MRI for cancer and other biological applications, and validate these in vivo; (iii) allow long-term monitoring of metabolism by development of HP 13C probes with extended hyperpolarization lifetime.
We have achieved ~80,000-fold signal enhancement of 13C-allypyruvate and 20,000-fold of pyruvate in MRI by improvement of the procedures of para-hydrogenation and following proton to carbon polarization transfer, which polarization level is high enough to conduct metabolic MRI. We also developed a partial-k space image acquisition for chemical shift imaging and deep learning image reconstruction technique to boost image data acquisition, shortening an image acquisition time to a fifth of default sequence.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Hyperpolarization is a means to obtain ~10000-fold signal enhancement in MRI, enabling visualization of otherwise undetectable biological compounds. Recently-developed side-arm (SA) para-hydrogen induced polarization (PHIP) presents a cost-effective method for producing hyperpolarized 13C for in vivo metabolic MRI. Our research goals are: (i) validate 13C-pyruvate polarized by SA-PHIP as an in vivo metabolic probe in small-animal disease models; (ii) expand the current suite of 13C probes that can be polarized by PHIP for metabolic MRI for cancer and other biological applications, and validate these in vivo; (iii) allow long-term monitoring of metabolism by development of HP 13C probes with extended hyperpolarization lifetime.
By improvement of the procedures of para-hydrogenation and following proton to carbon polarization transfer, we have successfully achieved ~80,000-fold signal enhancement of 13C-allypyruvate and 20,000-fold of pyruvate in MRI compared to the thermal signal at 1.5T using the cost effective PHIP technique, which polarization level is high enough to conduct hyperpolarized 13C metabolic MRI. We also developed a partial-k space image acquisition for chemical shift imaging and deep learning image reconstruction technique to boost image data acquisition, shortening an image acquisition time to a fifth of default sequence.
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| 今後の研究の推進方策 |
The polarization of 13C-pyruvate by a PHIP technique is going to be further improved by optimizing the procedure of hydrolysis of alcohol side-arm, and plan to apply the SA PHIP polarized 13C-pyuvate for metabolic imaging of xenografts of hepatic cancer and squamous cell carcinoma. The image quality will be compared to the images obtained by the standard DNP based hyperpolarization technique. We also expand the developed SA PHIP technique to other useful metabolic probe such as 13C-fumarate for non-invasive necrosis imaging. In parallel, to maximize the information available from 13C-pyruvate metabolic imaging experiments, we will further optimize existing imaging strategies to maximize the temporal resolution of dynamic metabolic imaging, and to develop tailored image acquisition techniques for our desired applications.
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