High resolution 3D Deuterium Metabolic Imaging of the human brain using bSSFP with concentric ring trajectory readout at 7T

Motivation: Deuterium metabolic imaging (DMI) suffers from inherently low SNR, which can be enhanced using balanced-steady-state-free-precession (bSSFP) pulse design. Higher SNR can be traded for increased spatial resolution using fast concentric ring trajectory (CRT) sampling. Goal(s): To develop and implement a 3D-bSSFP-DMI sequence for whole-brain DMI in humans at 7T. Approach: A bSSFP sequence module was combined with 3D-CRT sampling and metabolic maps of water/glucose/glutamate+glutamine were dynamically acquired in 4 healthy volunteers. Results: A 2-4-fold SNR increase was observed for DMI maps using bSSFP-DMI compared to FID-CRT-DMI, which allowed for increased spatial resolution (0.75ml to 0.36ml), while maintaining sufficient quality. Impact: Improving SNR and consequently spatial resolution of deuterium metabolic imaging (DMI) data is crucial to push DMI towards clinical application. bSSFP-CRT sequences combined with appropriate reconstruction and metabolite separation can facilitate this transition.