Correction of time-dependent phase fluctuations in diffusion-weighted MRS at high b-values with external phantom reference

Motivation: Diffusion-weighted MRS (dMRS) generates field fluctuations that distort spectral line shapes. Traditional water reference scans can be noisy at high b-values and fail to correct the spectra. Goal(s): This study aims to (1) map field fluctuations, (2) develop a stable phantom reference, (3) validate it against water scans in high-b-value acquisitions, and (4) extract diffusion properties. Approach: Spatial field fluctuations were mapped with a high-viscosity silicone oil phantom, and its performance in phase correction was compared to water reference scans in simulations and invivo. Results: The phantom reference was used to successfully correct invivo dMRS data up to a b-value of 37 ms/μm². Impact: This research can help improve dMRS data quality at high b-values by correcting signal distortions with a phantom reference scan. This reduces scanning time in human studies and makes dMRS more practical for clinical use.