Abstract #3608

Multi-Echo EPI with Parallel Transmission Z-Shimming for Increased Sensitivity in BOLD fMRI

Benedikt A. Poser¹, Cungeng Yang¹, Weiran Deng¹, Vijayanand Alagappan^2,3, Lawrence L. Wald^2,4, V. Andrew Stenger¹

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.