Abduljalil A M, Rath D P, Hui Z, Aletras A H, McCartney W C, Robitaille P M
Department of Radiology, Ohio State University Medical Center, Columbus 43210, USA.
Invest Radiol. 1996 Oct;31(10):611-8. doi: 10.1097/00004424-199610000-00002.
A modified Fourier Series Window (FSW) method is introduced that provides a simple, reasonably accurate, solution to spatial localization for layers in nuclear magnetic resonance (NMR) spectroscopy. This method was developed because signal originating from spins immediately adjacent to the coil plane can leak into standard FSW localized spectra obtained from more distal layers.
The B1 profile of the surface coil and a priori sample knowledge were used to generate modified FSW coefficients that largely compensate for contamination from proximal layers. These modified coefficients were used to acquire spatially localized spectra from a three-layered phantom containing inorganic phosphate, phosphocreatine, and pyrophosphate. Spatially localized spectra also were obtained from the open-chest canine myocardium.
The modified Fourier Series Window approach was validated using a quality assurance phantom. This method was then applied to the transmural analysis of 13C-containing metabolites in the in vivo canine myocardium during 3-(13)C sodium pyruvate infusion (n = 10). In vivo NMR spectra were characterized by resonances corresponding to the C2, C3, and C4 carbons of glutamic acid and to endogenous triacyglycerides and surface lipids. A transmural trend in metabolites could be observed under these conditions. This trend, however, was likely to result from the interference of surface lipids in the epicardial layer.
The authors demonstrate that the modified Fourier Series Window method can be applied in situations where signal-to-noise considerations limit the applicability of more sophisticated spatial localization methods. In addition, the authors report a slight gradient in the endogenous triacylglyceride resonance, which is likely to originate from the presence of surface lipids.
引入了一种改进的傅里叶级数窗（FSW）方法，该方法为核磁共振（NMR）波谱中层的空间定位提供了一种简单且相当准确的解决方案。开发此方法是因为源自紧邻线圈平面自旋的信号可能会泄漏到从更远层获得的标准FSW定位波谱中。
利用表面线圈的B1分布和先验样本知识生成改进的FSW系数，该系数在很大程度上补偿了近端层的污染。这些改进的系数用于从包含无机磷酸盐、磷酸肌酸和焦磷酸的三层模型中获取空间定位波谱。还从开胸犬心肌中获得了空间定位波谱。
使用质量保证模型验证了改进的傅里叶级数窗方法。然后将该方法应用于在输注3 -（13）C丙酮酸钠期间对体内犬心肌中含13C代谢物的透壁分析（n = 10）。体内NMR波谱的特征在于与谷氨酸的C2、C3和C4碳以及内源性三酰甘油和表面脂质相对应的共振峰。在这些条件下可观察到代谢物的透壁趋势。然而，这种趋势可能是由于心外膜层中表面脂质的干扰所致。
作者证明，在信噪比考虑限制了更复杂空间定位方法适用性的情况下，改进的傅里叶级数窗方法可以应用。此外，作者报告了内源性三酰甘油共振存在轻微梯度，这可能源于表面脂质的存在。
