In vivo diffusion-weighted imaging on a point-of-care 46mT Halbach MRI scanner

Motivation: Low-field MRIs for point-of-care (POC) applications are emerging, especially for low- and middle-income countries and intensive care and emergency units. Diffusion-weighted imaging (DWI) is crucial for clinical practice, requiring robust DWI protocols on POC scanners. Goal(s): Our goal was to implement a robust DWI sequence on our 46mT Halbach-based POC scanner. Approach: Due to B0 inhomogeneities and gradient constraints, we opted for a 3D turbo-spin echo sequence with a DW spin echo pre-module. We tested the sequence using a quantitative phantom and in vivo. Results: We obtained clean diffusion maps in phantom and in vivo, although diffusion coefficients are currently still slightly overestimated. Impact: We implemented a DWI sequence on a 46mT MRI and acquired data in healthy brains. We evaluated the feasibility of acquiring under-sampled data to fasten acquisition and to use b-values similar to the ones used in clinical practice.