Three-dimensional spectroscopic imaging with time-varying gradients.
A spectroscopic imaging sequence with a time-varying readout gradient in the slice selection direction is used to image multiple contiguous slices. For a given voxel size, the imaging time and signal-to-noise ratio of the three-dimensional spectroscopic sequence are the same as for a single slice acquisition without the oscillating readout gradient. The data reconstruction employs a gridding algorithm in two dimensions to interpolate the nonuniformly sampled data onto a Cartesian grid, and a fast Fourier transform in four dimensions: three spatial dimensions and the spectral dimension. The method is demonstrated by in vivo imaging of NAA in human brain at 1.5 T with 10 slices of 16 x 16 pixels spectroscopic images acquired in a total scan time of 17 min.
Adalsteinsson
E
E
Department of Electrical Engineering, Stanford University, California, USA.
Irarrazabal
P
P
Spielman
D M
DM
Macovski
A
A
D000465:Algorithms; D001921:Brain / Q000378:metabolism*; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors