Resting State fMRI Using Multi Echo EPI (ME-EPI): A Study of Echo Time Dependence of Sensitivity

Deqiang Qiu¹, Thomas Christen¹, Jae Mo Park¹, Michael E. Moseley¹, Greg Zaharchuk¹

Resting state fMRI (RS-fMRI) using BOLD has attracted significant interests recently. However, the relative sensitivity of RS-fMRI with respect to echo time has not been characterized. In this study, we developed a multi-echo EPI sequence with parallel imaging to study the effect of echo time on the sensitivity of RS-fMRI. We found that the sensitivity of RS-fMRI increases with echo time up to 58ms and has no significantly changes when increasing echo time further to 78ms. The benefits of reduction of EPI-related distortion using parallel imaging as well as combination of multiple echoes are also discussed.