Optimization of Echo Time in Direct Detection of Neuronal Currents with MRI

Qingfei Luo¹, Jia-Hong Gao¹

To detect the weak neuronal current MRI (ncMRI) signal, the imaging parameters (e.g., echo time) need to be optimized to achieve the maximum detection sensitivity. In this study, by theoretical modeling, we estimated the optimal echo time (TE) in a typical in-vivo ncMRI experiment using gradient-echo EPI pulse sequence. The results show that the optimal TE for detecting ncMRI magnitude/phase signal is 92/56ms in human brain at 3T. Also, the difference of optimal TE between magnitude and phase signals suggests that a dual-echo pulse sequence should be used to achieve the highest sensitivity to both signals in a MRI scan.