Optimal echo-time selection for MRSI acquisition

Long acquisition time is one of the major challenges of magnetic resonance spectroscopic imaging (MRSI). Patient discomfort, motion artifacts and cost will increase when the acquisition time lengthens. In order to accelerate the data collecting process, we propose to apply sequential backward selection (SBS) to optimal echo-time selection and then use these selected echo-time values in echo-planar imaging (EPI) acquisition. For multi-echo EPI, our method allows multiple echo-time values to be selected simultaneously. As a result, in each excitation, multiple k-space frames can be acquired and the acquisition time reduces further. Phantom experiments demonstrate the feasibility of the proposed method. We compare the reconstructed spatial and spectral results from this new technique, standard MRSI, equal echo-time selection and random echo-time selection. Comparisons show that the proposed method can achieve similar results to standard MRSI while greatly reducing the data quantity requirements.