Assessment of human myocardial metabolism by nuclear magnetic resonance spectroscopy using proton excitation

Proton （D11H） nuclear magnetic resonance （NMR） spectroscopy （MRS） was performed on a clinical （1.5-T）magnetic-resonance-imaging system。接收--只有柔性表面线圈被放置在左边的入口处，有一个物体。Voxels在1.5 s的重复时间内保持放松到最低限度，具有刺激的回波采集模式（STEAM）或点解析光谱（PRESS）。我们收集了8个免费的索引日期（FID），用于水信号，而没有水抑制256个水抑制的FID用于生物信号。总产量是根据每百万分之3.0份的N甲基共振率进行了识别和测量，并将水信号作为参考值为4.75 ppm。To measure total myocardial creatine we used the tissue-water signal in the unsuppressedイイD11エD1H MRS spectrum as a concentration reference。生物信号的正常化是由相同的水信号引起的，使其从不同的结果中的体积大小、位置和异质性在接收器-线圈接收中的系统影响。Creatine resonance appeared at 3.06±0.07 ppm by STEAM method and at 3.18±0.07 ppm by PRESS。在一个清晰的间隔七点中，肌红蛋白的总含量为25.7 μmol/g，重量为蒸汽。These Findings Suggest that quantitative human myocardial D11 ye D1H MRS is feasible both by STEAM and by PRESS and that the两种方法yield similar myocardial creatine content values。

Proton (ィイD11ィエD1H) nuclear magnetic resonance (NMR) spectroscopy (MRS) was performed on a clinical (1.5-T) magnetic-resonance-imaging system. A receive-only flexible surface coil was placed over the left ventricle with subjects in the supine position. Voxels were localized to 8 ml with stimulated echo acquisition mode (STEAM) or point-resolved spectroscopy (PRESS) at a repetition time of 1.5 s to keep relaxation distortions to a minimum. We collected 8 free induction decays (FID) for water signal without water suppression before acquiring 256 water-suppressed FID's for creatine signal. Total creatine was identified and measured based on its N-methyl resonance at around 3.0 parts per million (ppm) taking water signal as a reference at 4.75 ppm. To measure total myocardial creatine we used the tissue-water signal in the unsuppressed ィイD11ィエD1H MRS spectrum as a concentration reference. Normalization of creatine signal by the water signal from the same voxel eliminates the systematic effects that result from differences in voxel size, location, and heterogeneity in the receiver-coil reception. Creatine resonance appeared at 3.06±0.07 ppm by STEAM method and at 3.18±0.07 ppm by PRESS. Total myocardial creatine content in a scarred interventricular septum was 25.7 μmol/g wet weight by STEAM. These findings suggest that quantitative human myocardial ィイD11ィエD1H MRS is feasible both by STEAM and by PRESS and that the two methods yield similar myocardial creatine content values.