Motivation: Downfield magnetic resonance spectroscopic imaging (DF-MRSI) at high magnetic field strengths is expected to have superior signal-to-noise ratios (SNR) and spectral resolution compared to lower field. However, to date there have been no studies systematically comparing DF-MRSI across different field strengths. Goal(s): To quantitatively compare SNR, linewidths, and Cramér-Rao Lower Bounds (CRLB) for amide resonances in the human brain measured at 3 and 7T using (DF-MRSI). Approach: Seven healthy volunteers were scanned at 3T and 7T using closely-matched DF-MRSI protocols. Results: DF-MRSI at 7T showed 86% increased SNR and 57% decreased CRLB values compared to 3T. Water linewidths were narrower at 3T. Impact: Amide mapping using DF-MRSI at 7T showed significantly superior precision compared to 3T, and therefore is the preferred field strength for future research studies of DF metabolites.
Özdemir et al. (Tue,) studied this question.