Hybrid Three Dimensional (1D‐Hadamard, 2D‐Chemical Shift Imaging) Phosphorus Localized Spectroscopy of Phantom and Human Brain

Abstract

A hybrid of two localized spectroscopy techniques, chemical shift imaging (CSI) and Hadamard spectroscopic imaging (HSI), is used to obtain an array of 16 x 16 x 4 (3 x3 x 3 cm³ voxels) proton-decoupled phosphorus (³¹P) spectra of human brain. For equal spatial resolution, this organ's oblate shape requires fewer axial than coronal or sagittal slices. These different spatial requirements are well suited to 1D, 4^th order, transverse HSI in the axial direction, combined with 2D 16 x 16 CSI in the other two orientations. The reduced localization matrix (16 x 16 x 4 over just the brain versus a cubic-16 x 16 x 16 matrix of equal resolution, over the entire head) may proportionally shorten data acquisition if the voxel size is not signal-to-noise limited. In addition, the use of Hadamard encoding can improve the intervoxel spectral isolation.