Sensitivity and resolution improvement for in-vivo magnetic resonance current density imaging (MRCDI) of the human brain

Effective use of transcranial electrical stimulation (TES) in clinical and neuroscience applications requires the exact knowledge of TES currents. MRCDI uses MRI to measure the TES-induced magnetic fields for estimating the underlying current flow distributions. Their accuracy highly depends on the sensitivity and spatial resolution of the MR measurements. Here, we propose an advanced gradient-echo-based MRCDI method utilizing an optimized spoiling, acquisition-weighting, and navigators to achieve a noise sensitivity of 84pT at 2×2×3mm3 resolution for a total scan time of less than five minutes. We test the method's performance by phantom and human in-vivo experiments for two TES injection profiles