Barskiy Danila A, Kovtunov Kirill V, Koptyug Igor V, He Ping, Groome Kirsten A, Best Quinn A, Shi Fan, Goodson Boyd M, Shchepin Roman V, Truong Milton L, Coffey Aaron M, Waddell Kevin W, Chekmenev Eduard Y
Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3 A Institutskaya St. Novosibirsk 630090 (Russia); Novosibirsk State University, 2 Pirogova St. Novosibirsk 630090 (Russia).
Chemphyschem. 2014 Dec 15;15(18):4100-7. doi: 10.1002/cphc.201402607. Epub 2014 Nov 3.
By using 5.75 and 47.5 mT nuclear magnetic resonance (NMR) spectroscopy, up to 10(5)-fold sensitivity enhancement through signal amplification by reversible exchange (SABRE) was enabled, and subsecond temporal resolution was used to monitor an exchange reaction that resulted in the buildup and decay of hyperpolarized species after parahydrogen bubbling. We demonstrated the high-resolution low-field proton magnetic resonance imaging (MRI) of pyridine in a 47.5 mT magnetic field endowed by SABRE. Molecular imaging (i.e. imaging of dilute hyperpolarized substances rather than the bulk medium) was conducted in two regimes: in situ real-time MRI of the reaction mixture (in which pyridine was hyperpolarized), and ex situ MRI (in which hyperpolarization decays) of the liquid hyperpolarized product. Low-field (milli-Tesla range, e.g. 5.75 and 47.5 mT used in this study) parahydrogen-enhanced NMR and MRI, which are free from the limitations of high-field magnetic resonance (including susceptibility-induced gradients of the static magnetic field at phase interfaces), potentially enables new imaging applications as well as differentiation of hyperpolarized chemical species on demand by exploiting spin manipulations with static and alternating magnetic fields.
通过使用5.75和47.5 mT的核磁共振（NMR）光谱，借助可逆交换信号放大（SABRE）实现了高达10⁵倍的灵敏度增强，并利用亚秒级时间分辨率监测了在对氢鼓泡后导致超极化物质积累和衰减的交换反应。我们展示了在由SABRE赋予的47.5 mT磁场中吡啶的高分辨率低场质子磁共振成像（MRI）。分子成像（即对稀超极化物质而非整体介质进行成像）在两种情况下进行：反应混合物（其中吡啶被超极化）的原位实时MRI，以及液体超极化产物的异位MRI（其中超极化衰减）。低场（毫特斯拉范围，例如本研究中使用的5.75和47.5 mT）对氢增强的NMR和MRI不受高场磁共振的限制（包括相界面处静态磁场的磁化率诱导梯度），通过利用静态和交变磁场的自旋操纵，有可能实现新的成像应用以及按需区分超极化化学物质。
