High-Resolution Phase Correction in Overdiscrete Spectroscopic Imaging Reconstruction using Piecewise Polynomial Interpolation

A full phase correction at high resolution is incorporated into the overdiscrete reconstruction for ¹H MR Spectroscopic Imaging (MRSI). This allows to correct spectral artifacts generated by phase disturbances and increase SNR in one step, hence improving metabolite detection for fast MRSI acquisitions at short echo times. The phase correction term is approximated as a piecewise polynomial, fitted from a water reference scan that is acquired simultaneously with the metabolite signal. The method was applied to standard phase encoded MRSI and Echo-Planar Spectroscopic Imaging (EPSI) brain scans showing comparable improvements.