Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118, Kiel, Germany.
Western University, 1151 Richmond St, London, ON, N6A 3K7, Canada.
Nat Commun. 2023 Aug 8;14(1):4774. doi: 10.1038/s41467-023-40539-9.
Nuclear spin hyperpolarization is a quantum effect that enhances the nuclear magnetic resonance signal by several orders of magnitude and has enabled real-time metabolic imaging in humans. However, the translation of hyperpolarization technology into routine use in laboratories and medical centers is hampered by the lack of portable, cost-effective polarizers that are not commercially available. Here, we present a portable, automated polarizer based on parahydrogen-induced hyperpolarization (PHIP) at an intermediate magnetic field of 0.5 T (achieved by permanent magnets). With a footprint of 1 m, we demonstrate semi-continuous, fully automated H hyperpolarization of ethyl acetate-d6 and ethyl pyruvate-d6 to P = 14.4% and 16.2%, respectively, and a C polarization of 1-C-ethyl pyruvate-d6 of P = 7%. The duty cycle for preparing a dose is no more than 1 min. To reveal the full potential of H hyperpolarization in an inhomogeneous magnetic field, we convert the anti-phase PHIP signals into in-phase peaks, thereby increasing the SNR by a factor of 5. Using a spin-echo approach allowed us to observe the evolution of spin order distribution in real time while conserving the expensive reagents for reaction monitoring, imaging and potential in vivo usage. This compact polarizer will allow us to pursue the translation of hyperpolarized MRI towards in vivo applications further.
核自旋极化是一种量子效应，可以将核磁共振信号增强几个数量级，从而实现人类实时代谢成像。然而，将极化技术转化为实验室和医疗中心的常规使用，受到缺乏便携式、具有成本效益且非商业可用的极化器的阻碍。在这里，我们提出了一种基于中间磁场（通过永磁体实现的 0.5T）下的 Para 氢诱导极化（PHIP）的便携式自动极化器。我们的极化器占地面积为 1 平方米，演示了乙酸乙酯-d6 和乙基丙酮酸-d6 的半连续、全自动 H 极化，分别达到 P=14.4%和 16.2%，1-C-乙基丙酮酸-d6 的 C 极化达到 P=7%。制备剂量的工作周期不超过 1 分钟。为了揭示非均匀磁场中 H 极化的全部潜力，我们将反相信号 PHIP 转换为同相信号峰，从而将 SNR 提高了 5 倍。使用自旋回波方法，我们可以在实时观察自旋有序分布的同时，节省昂贵的试剂用于反应监测、成像和潜在的体内应用。这种紧凑型极化器将使我们能够进一步推进超极化 MRI 在体内应用的转化。
