Burns Michael J, Rayner Peter J, Green Gary G R, Highton Louise A R, Mewis Ryan E, Duckett Simon B
Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
J Phys Chem B. 2015 Apr 16;119(15):5020-7. doi: 10.1021/acs.jpcb.5b00686. Epub 2015 Apr 6.
Traditional (31)P NMR or MRI measurements suffer from low sensitivity relative to (1)H detection and consequently require longer scan times. We show here that hyperpolarization of (31)P nuclei through reversible interactions with parahydrogen can deliver substantial signal enhancements in a range of regioisomeric phosphonate esters containing a heteroaromatic motif which were synthesized in order to identify the optimum molecular scaffold for polarization transfer. A 3588-fold (31)P signal enhancement (2.34% polarization) was returned for a partially deuterated pyridyl substituted phosphonate ester. This hyperpolarization level is sufficient to allow single scan (31)P MR images of a phantom to be recorded at a 9.4 T observation field in seconds that have signal-to-noise ratios of up to 94.4 when the analyte concentration is 10 mM. In contrast, a 12 h 2048 scan measurement under standard conditions yields a signal-to-noise ratio of just 11.4. (31)P-hyperpolarized images are also reported from a 7 T preclinical scanner.
传统的（31）P核磁共振（NMR）或磁共振成像（MRI）测量相对于（1）H检测而言灵敏度较低，因此需要更长的扫描时间。我们在此表明，通过与仲氢的可逆相互作用对（31）P核进行超极化，可以在一系列含有杂芳基基序的区域异构体膦酸酯中实现显著的信号增强，合成这些膦酸酯是为了确定极化转移的最佳分子支架。对于一种部分氘代的吡啶基取代膦酸酯，（31）P信号增强了3588倍（极化率为2.34%）。当分析物浓度为10 mM时，这种超极化水平足以在9.4 T观测场中在数秒内记录体模的单次扫描（31）P MR图像，其信噪比高达94.4。相比之下，在标准条件下进行12小时2048次扫描测量，得到的信噪比仅为11.4。还报道了来自7 T临床前扫描仪的（31）P超极化图像。
