Diffusion tensor brain imaging at 0.55T: A feasibility study

Abstract Purpose To investigate the feasibility of diffusion tensor brain imaging at 0.55T with comparisons against 3T. Methods Diffusion tensor imaging data with 2 mm isotropic resolution was acquired on a cohort of five healthy subjects using both 0.55T and 3T scanners. The signal‐to‐noise ratio (SNR) of the 0.55T data was improved using a previous SNR‐enhancing joint reconstruction method that jointly reconstructs the entire set of diffusion weighted images from k‐space using shared‐edge constraints. Quantitative diffusion tensor parameters were estimated and compared across field strengths. We also performed a test–retest assessment of repeatability at each field strength. Results After applying SNR‐enhancing joint reconstruction, the diffusion tensor parameters obtained from 0.55T data were strongly correlated () with those obtained from 3T data. Test–retest analysis showed that SNR‐enhancing reconstruction improved the repeatability of the 0.55T diffusion tensor parameters. Conclusion High‐resolution in vivo diffusion MRI of the human brain is feasible at 0.55T when appropriate noise‐mitigation strategies are applied.