High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
NMR Biomed. 2014 Apr;27(4):478-85. doi: 10.1002/nbm.3084. Epub 2014 Feb 24.
Phosphorus ((31) P) MRS is a powerful tool for the non-invasive investigation of human liver metabolism. Four in vivo (31) P localization approaches (single voxel image selected in vivo spectroscopy (3D-ISIS), slab selective 1D-ISIS, 2D chemical shift imaging (CSI), and 3D-CSI) with different voxel volumes and acquisition times were demonstrated in nine healthy volunteers. Localization techniques provided comparable signal-to-noise ratios normalized for voxel volume and acquisition time differences, Cramer-Rao lower bounds (8.7 ± 3.3%1D-ISIS , 7.6 ± 2.5%3D-ISIS , 8.6 ± 4.2%2D-CSI , 10.3 ± 2.7%3D-CSI ), and linewidths (50 ± 24 Hz1D-ISIS , 34 ± 10 Hz3D-ISIS , 33 ± 10 Hz2D-CSI , 34 ± 11 Hz3D-CSI ). Longitudinal (T1 ) relaxation times of human liver metabolites at 7 T were assessed by 1D-ISIS inversion recovery in the same volunteers (n = 9). T1 relaxation times of hepatic (31) P metabolites at 7 T were the following: phosphorylethanolamine - 4.41 ± 1.55 s; phosphorylcholine - 3.74 ± 1.31 s; inorganic phosphate - 0.70 ± 0.33 s; glycerol 3-phosphorylethanolamine - 6.19 ± 0.91 s; glycerol 3-phosphorylcholine - 5.94 ± 0.73 s; γ-adenosine triphosphate (ATP) - 0.50 ± 0.08 s; α-ATP - 0.46 ± 0.07 s; β-ATP - 0.56 ± 0.07 s. The improved spectral resolution at 7 T enabled separation of resonances in the phosphomonoester and phosphodiester spectral region as well as nicotinamide adenine dinucleotide and uridine diphosphoglucose signals. An additional resonance at 2.06 ppm previously assigned to phosphoenolpyruvate or phosphatidylcholine is also detectable. These are the first (31) P metabolite relaxation time measurements at 7 T in human liver, and they will help in the exploration of new, exciting questions in metabolic research with 7 T MR.
磷 ((31) P) MRS 是一种强大的工具，可用于非侵入性研究人体肝脏代谢。本研究在 9 名健康志愿者中展示了 4 种体内 (31) P 定位方法（在体单容积成像选择波谱（3D-ISIS）、薄片选择 1D-ISIS、2D 化学位移成像（CSI）和 3D-CSI），具有不同的体素体积和采集时间。定位技术提供了可比的信噪比，归一化了体素体积和采集时间差异、克拉默-劳下限（8.7±3.3%1D-ISIS，7.6±2.5%3D-ISIS，8.6±4.2%2D-CSI，10.3±2.7%3D-CSI）和线宽（50±24 Hz1D-ISIS，34±10 Hz3D-ISIS，33±10 Hz2D-CSI，34±11 Hz3D-CSI）。在同一志愿者中（n=9），通过 1D-ISIS 反转恢复评估了人肝代谢物在 7T 下的纵向（T1）弛豫时间。在 7T 下，肝 (31) P 代谢物的 T1 弛豫时间如下：磷乙醇胺 - 4.41±1.55s；磷酸胆碱 - 3.74±1.31s；无机磷 - 0.70±0.33s；甘油 3-磷酸乙醇胺 - 6.19±0.91s；甘油 3-磷酸胆碱 - 5.94±0.73s；γ-三磷酸腺苷（ATP） - 0.50±0.08s；α-ATP - 0.46±0.07s；β-ATP - 0.56±0.07s。在 7T 下，光谱分辨率的提高使得磷单酯和磷酯谱区的共振以及烟酰胺腺嘌呤二核苷酸和尿苷二磷酸葡萄糖信号得以分离。以前被分配给磷酸烯醇丙酮酸或磷脂酰胆碱的 2.06ppm 处的附加共振也可检测到。这些是在人类肝脏中进行的首次 7T 下 (31) P 代谢物弛豫时间测量，它们将有助于探索代谢研究中具有 7T MR 的新的令人兴奋的问题。
