COMPARISON OF K-SPACE SAMPLING SCHEMES FOR MULTIDIMENSIONAL MR SPECTROSCOPIC IMAGING

For clinical P-31 MR spectroscopic imaging (MRSI) studies, where signa l averaging is necessary, some improvement of sensitivity and spatial response function may be achieved by acquiring data over a spherical k -space volume and varying the number of averages acquired in proportio n to the desired spatial filter, Eight different k-space sampling sche mes are compared through simulations that provide graphs of the spatia l response functions (SRF), and tabulations of voxel volumes, relative signal-to-noise ratios (SNR), and relative data collection efficienci es (SNR per unit volume over the same time). All schemes were based on practical experiments, each of which could be implemented in the same length of time, The results show that in comparison with cubic k-spac e sampling with the same number of signal averages at each point, sphe rical and acquisition-weighted k-space sampling can be used to achieve reduced Gibbs ringing along the principal axes directions, and thus r educed contamination from adjacent tissue in these directions, without degradation of voxel volume or SNR.