Improved receive coil signal combination for large volume single voxel spectroscopy at ultra-high field

Motivation: Spectroscopic detection of low concentration metabolites (< 1mM) requires either lengthy signal averaging or large volume voxels. The latter can lead to significant variations in B0 across the volume, especially at ultrahigh field. Goal(s): Correct for B0 heterogeneity in large volume SVS when detecting with multi-channel receive coils. Approach: Using a metric for receive signal similarity, apply frequency and phase alignment of individual channel signals, prior to coil combination. Results: The method was applied to 18 in vivo scans of 1H brain spectra at 7 T. Narrower linewidths and increased SNR were observed for water and down-field NAD+ resonances. Impact: This approach provides an automated and robust method to improve spectral resolution and signal-to-noise ratio with large volume single voxel spectroscopy of low concentration metabolites when using multichannel receive arrays.