McLean M A, Woermann F G, Barker G J, Duncan J S
MRI Unit, National Society for Epilepsy, Chalfont St. Peter, Buckinghamshire, UK.
Magn Reson Med. 2000 Sep;44(3):401-11. doi: 10.1002/1522-2594(200009)44:3<401::aid-mrm10>3.0.co;2-w.
Quantitative analysis of (1)H-magnetic resonance spectroscopic imaging (MRSI) data was developed using the user-independent spectral analysis routine LCModel. Tissue segmentation was performed using statistical parametric mapping software (SPM 96), and the results were used to correct for cerebrospinal fluid contamination. A correction was developed for the imperfections in the spectroscopic excitation profile in order to improve the uniformity of metabolite images. After validation in phantoms, these techniques were applied to study differences in metabolite concentrations between gray and white matter in normal volunteers (n = 13). A positive correlation was found between concentration and gray matter content for most metabolites studied. The estimated ratios of metabolite concentration in gray vs. white matter were: N-acetyl aspartate + N-acetyl aspartyl glutamate (NAc) = 1.16+/- 0.11; creatine = 1.7+/-0.3; glutamate + glutamine = 2.4+/-0.5; myo-inositol = 1.6+/-0.3; choline = 0.9+/-0.2. The ratio of NAc/Cr was negatively correlated with gray matter content: gray/white = 0.69 +/-0.08. These methods will be useful in the evaluation of metabolite concentrations in MRSI voxels with mixed tissue composition in patient groups.
使用独立于用户的光谱分析程序LCModel对氢磁共振波谱成像（MRSI）数据进行定量分析。使用统计参数映射软件（SPM 96）进行组织分割，并将结果用于校正脑脊液污染。针对光谱激发轮廓中的缺陷开发了一种校正方法，以提高代谢物图像的均匀性。在体模中验证后，将这些技术应用于研究正常志愿者（n = 13）灰质和白质之间代谢物浓度的差异。在所研究的大多数代谢物中，发现浓度与灰质含量之间存在正相关。灰质与白质中代谢物浓度的估计比值为：N-乙酰天门冬氨酸+ N-乙酰天门冬氨酰谷氨酸（NAc）= 1.16±0.11；肌酸= 1.7±0.3；谷氨酸+谷氨酰胺= 2.4±0.5；肌醇= 1.6±0.3；胆碱= 0.9±0.2。NAc/Cr比值与灰质含量呈负相关：灰质/白质= 0.69±0.08。这些方法将有助于评估患者组中具有混合组织成分的MRSI体素中的代谢物浓度。
