REDUCED PHASE-ENCODING IN SPECTROSCOPIC IMAGING

The effect of different spatial-encoding (k-space) sampling distributi ons are evaluated for magnetic resonance spectroscopic imaging (MRSI) using Fourier reconstruction. Previously, most MRSI studies have used square or cubic k-space functions, symmetrically distributed. These st udies examine the conventional k-space distribution with spherical dis tribution, and 1/2 k-space acquisition, using computer simulation stud ies of the MRSI acquisition for three spatial dimensions and experimen tal results. Results compare the spatial response function, Gibbs ring ing effects, and signal contamination for different spatial-encoding d istribution functions. Results indicate that spherical encoding, in co mparison with cubic encoding, results in a modest improvement of the r esponse function with approximately equivalent spatial resolution for the same acquisition time. For spin-echo acquired data, reduced acquis ition times can readily be obtained using 1/2 k-space methods, with a concomitant reduction in signal to noise ratio.