Objective: We aimed to test the hypothesis that slice-by-slice prospective motion correction at 7T using an optical tracking system reduces the rate of false positive activations in an fMRI group study with a paradigm that involves task-correlated motion.
Materials and methods: Brain activation during right leg movement was measured using a block design on 15 volunteers, with and without prospective motion correction. Clearly erroneous activations were compared between both cases, at the individual level. Additionally, conventional group analysis was performed.
Results: The number of falsely activated voxels with T-values higher than 5 was reduced by 48% using prospective motion correction alone, without additional retrospective realignment. In the group analysis, the statistical power was increased - the peak T-value was 26% greater, and the number of voxels in the cluster representing the right leg was increased by a factor of 9.3.
Conclusion: Slice-by-slice prospective motion correction in fMRI studies with task-correlated motion can substantially reduce false positive activations and increase statistical power.
Keywords: False positive activations; Magnetic resonance imaging; Optical motion tracking; Prospective motion correction; fMRI.
© 2013.