Tae Kim1, Yoojin Lee1, Tiejun Zhao2, Hoby Hetherington1, and Jullie Pan1
1University of Pittsburgh, Pittsburgh, PA, United States, 2Siemens Medical Solution USA, INC, Pittsburgh, PA, United States
High
degree/order shimming was applied to improve field homogeneity thereby reducing
susceptibility-induced distortion in high resolution gradient-echo EPI using a
shim insert coil at 7T. Use of the shim insert improved the overall homogeneity
across the entire brain by 30% in comparison to conventional 1st&2nd
degree/order shimming. The susceptibility-induced displacement improved by more
than 2cm and the number of activated pixels increased by 150% with higher
degree shimming in regions such as the anterior temporal and frontal lobes. Our
study demonstrates that the use of higher order/degree shims improves GE-EPI
BOLD signal at high field.