Freeman Ray, Kupče Ēriks
Jesus College, Cambridge University, Cambridge, UK.
Top Curr Chem. 2012;316:1-20. doi: 10.1007/128_2010_103.
The Achilles heel of conventional multidimensional NMR spectroscopy is the long duration of the measurements, set by the Nyquist sampling condition and the resolution requirements in the evolution dimensions. Projection-reconstruction solves this problem by radial sampling of the evolution-domain signals, relying on Bracewell's Fourier transform slice/projection theorem to generate a set of projections at different inclinations. Reconstruction is implemented by one of three possible deterministic back-projection schemes (additive, lowest-value, or algebraic), or by a statistical model-fitting program. For simplicity the treatment focuses principally on the three-dimensional case, and then extends the analysis to four dimensions. The concept of hyperdimensional spectroscopy is described for dealing with even higher dimensions.
传统多维核磁共振波谱的致命弱点在于测量时间长，这是由奈奎斯特采样条件和演化维度中的分辨率要求所决定的。投影重建通过对演化域信号进行径向采样来解决这个问题，它依靠布雷克韦尔傅里叶变换切片/投影定理生成一组不同倾角的投影。重建可通过三种可能的确定性反投影方案（加法、最小值或代数）之一来实现，也可通过统计模型拟合程序来实现。为简单起见，论述主要集中在三维情况，然后将分析扩展到四维。文中还描述了用于处理更高维度的超维波谱概念。
