Buchthal S D, Thoma W J, Taylor J S, Nelson S J, Brown T R
Department of Biochemistry, Gray Freshwater Biological Institute, University of Minnesota, Navarre 55392.
NMR Biomed. 1989 Dec;2(5-6):298-304. doi: 10.1002/nbm.1940020520.
A procedure for obtaining T1 values for phosphorous metabolites in localized regions of human subjects, using a standard 1.5 T MR imager, is described. 31P spectra and T1 values localized to the liver, and to abdominal and calf muscle of healthy volunteers were obtained by means of a multi-slice spectroscopy technique, consisting of a chemical shift imaging (CSI) sequence with a B1-insensitive excitation and one dimension of phase encoding, used in conjunction with a surface coil. An examination consisting of proton imaging, shimming and collection of 31P progressive saturation spectroscopic data for T1 determination required 1 h to perform. Shimming on the signal from the body region detected by the surface coil gave spectra of excellent spectral resolution. Quantification of all peaks in the localized 31P spectra was carried out with the PIQABLE algorithm, and T1 values were calculated for inorganic phosphate (Pi), the phosphodiester region, and the ATP alpha-, beta- and gamma peaks of liver, and for calf muscle Pi, phosphocreatine (PCr), and the three ATP peaks. The precisions of the measurement and of the entire process for obtaining and quantifying localized spectra by one-dimensional CSI were determined, and the accuracy of T1 values obtained by this means was verified. The temporal variation in T1 values obtained in a series of examinations of a single normal subject was also assessed. The consistency of the T1 values obtained in this study with in vivo T1 values obtained by other techniques is a stringent test of accuracy of localized spectra obtained with CSI.
本文描述了一种使用标准1.5T磁共振成像仪获取人体受试者局部区域磷代谢物T1值的方法。通过多切片光谱技术，结合表面线圈，获得了健康志愿者肝脏、腹部肌肉和小腿肌肉的31P光谱及T1值。该技术采用具有B1不敏感激发和一维相位编码的化学位移成像（CSI）序列。进行一次包括质子成像、匀场以及采集用于T1测定的31P逐次饱和光谱数据的检查需要1小时。对表面线圈检测到的身体区域信号进行匀场后，得到了具有出色光谱分辨率的光谱。使用PIQABLE算法对局部31P光谱中的所有峰进行定量，并计算了肝脏无机磷酸盐（Pi）、磷酸二酯区域、ATP的α、β和γ峰以及小腿肌肉Pi、磷酸肌酸（PCr）和三个ATP峰的T1值。确定了通过一维CSI获取和定量局部光谱的测量精度和整个过程的精度，并验证了通过这种方法获得的T1值的准确性。还评估了在对一名正常受试者进行的一系列检查中获得的T1值的时间变化。本研究中获得的T1值与通过其他技术获得的体内T1值的一致性，是对用CSI获得的局部光谱准确性的严格检验。
