Neuromelanin MRI using 2D GRE and deep learning: considerations for improving the visualization of substantia nigra and locus coeruleus

An optimized clinically feasible neuromelanin MRI imaging protocol for visualising the SN and LC simultaneously using deep learning reconstruction is presented. For a 2D sequence we set out to optimize the flip-angle for optimal combined SN and LC depiction. We also experimented with combinations of anisotropic and isotropic in-plane resolution, partial vs full echoes and the number of averages. Phantom and in-vivo experiments on three healthy volunteers illustrate that high-resolution imaging combined with deep-learning denoising shows good depiction of the SN and LC with a clinically feasible sequence of 7 minutes.