Frontal Cortex fMRI at 7T: Escaping Flat Minimum Traps in Higher-Order B0 Shimming Algorithms

unprocessed functional images (volunteer 2), acquired with a FM shim (a,b) and with an ST shim (c,d). The comparison especially of the sagital images (a,c) demonstrates the ability of the ST shim, to restore signal in the FC area. Figure 1: EPIs of three different slices of a volunteer’s brain (volunteer 1) acquired with a FM and a ST shim, and an anatomical reference image (first column). The green arrows indicate the restored signal of the eyes and the brain structure between them Figure 2: B0 maps of three different slices of a volunteer’s brain (volunteer 1) with no shim, a FM shim and an ST shim. The images are overlaid with the ROI (white) and the ROLI (black) that have been used for the calculation of the ST shim.