HYBRID 3-DIMENSIONAL (1D-HADAMARD, 2D-CHEMICAL SHIFT IMAGING) PHOSPHORUS LOCALIZED SPECTROSCOPY OF PHANTOM AND HUMAN BRAIN

A hybrid of two localized spectroscopy techniques, chemical shift imag ing (CSI) and Hadamard spectroscopic imaging (HSI), is used to obtain an array of 16 x 16 x 4 (3 x 3 x 3 cm(3) voxels) proton-decoupled phos phorus (P-31) spectra of human brain. For equal spatial resolution, th is 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 matri x (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 spec tral isolation.