Fig. 6.

Example of false-positive activation due to signal leakage between simultaneously excited slices. The top image shows the suspected false-positive activation from an MB 6 scan of Volunteer 2 with Slice-GRAPPA (SG) reconstruction, originating from the voxel at the blue cross and aliasing into voxels at the yellow arrows. The horizontal dashed yellow lines indicate the six slices that were simultaneously excited and acquired with the blue cross slice. The yellow crosses indicate the alias locations due to the combined CAIPI shift of FOV/3 and in-plane GRAPPA 2. The bottom row of images shows the MB 1, MB 2, and MB 4 results from the same volunteer. No activation is seen within a 3 × 3 × 3 voxel ROI around the suspected false-positive locations from the MB 6 scan (yellow boxes). These three regions of activation from the MB 6 scan were therefore deemed to be false-positive activations.