3种信号处理方法在磁共振波谱中的应用比较

摘要

Objective To compare the application of three different kinds of signal processing methods: fast Fourier transform ( FFT) , wavelet transform ( WT) and singular value decomposition ( SVD) at magnetic resonance spectroscopy ( MRS). Methods Ten health volunteers were selected and scanned with the point-resolved spectroscopy (PRESS) sequence at frontal regions. The raw data were analyzed with FFT, WT and SVD comparatively. Results Except for the position of creatine (Cr) , the position of choline (Cho) , ratios of N-acetyl aspartate/creatine (NAA/Cr) and choline/creatine (Cho/Cr) had no significant differences between the three analyzing methods (P＞0. 05). But the positions of Cr and Cho were basically consistent with the reference in the results of the three mcthods. Otherwise, the ratios of NAA/Cr and Cho/Cr in the results of the WT were closer with the reference than the other methods. The WT method could distinguish the coupling signals of Glx while the SVD method had limitations and could not analyze them efficicntly. Conclusion The positions of the main metabolites of frontal regions are nicety with the three different mcthods,but comparation with the FFT and the SVD, the WT method shows an advantage for the ratio of NAA/Cr and Cho/Cr in analyzing the metabolites with low concentrations,while the SVD mcthod would be better in analyzing metabolites with high concentrations.%目的 比较傅立叶变换(FFT)、小波变换(WT)和奇异值分解(SVD)这3种信号处理方法在磁共振波谱技术中的应用.方法 使用PRESS序列采集10例健康成年人额叶MRS数据,并利用这3种方法对数据进行后处理,比较其分析结果.结果 (1)3种方法得到的结果中除Cr位置外,Cho位置、NAA/Cr与Cho/Cr相互间无显著性差异(P>0.05).所得结果的Cr、Cho位置与参考文献值基本一致.另外,Cho/Cr、NAA/Cr以WT的结果与文献值最为接近,但WT结果的标准差最大.(2)在对Glx进行分析时,WT能够将各个耦合峰有效地分开,而SVD则存在缺陷,无法对其进行有效的分析.结论 3种处理方法得到的代谢物峰的位置均比较准确.但在分析代谢物的相对含量时,对于较高含量的代谢物,使用SVD的方法结果更准确；若分析含量较低的代谢物信息,宜使用WT.