Benedikt A. Poser1, Cungeng Yang1,
Weiran Deng1, Vijayanand Alagappan2,3,
1University of Hawaii, John A. Burns School of Medicine, Honolulu, HI, United States; 2A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; 3Department of Biomedical Engineering, Tufts University, Medford, MA, United States; 4Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA, United States
Signal loss remains the most obdurate problem in gradient-echo BOLD fMRI. Here we address the issue by merging two highly promising techniques, parallel-transmission z-shimming and multi-echo EPI acquisition. ME-EPI has previously been shown to increase BOLD sensitivity over the entire brain; however it does not actively compensate for through-plane dephasing. This makes multi-channel transmission for the application of local corrective z-shims is highly complementary. The combined method is found to be more effective in reducing susceptibility artifacts than each individual approach; In vivo experiments reveal improved sensitivity in the frontal lobe, demonstrating the methods potential for fMRI application.