Prospective acquisition correction for head motion with image-based tracking for real-time fMRI

In functional magnetic resonance imaging (fMRI) head motion can corrupt the signal changes induced by brain activation. This paper describes a novel t echnique called Prospective Acquisition CorrEction (PACE) for reducing moti on-induced effects on magnetization history. Full three-dimensional rigid b ody estimation of head movement is obtained by image-based motion detection to a high level of accuracy. Adjustment of slice position and orientation, as well as regridding of residual volume to volume motion, is performed in real-time during data acquisition. Phantom experiments demonstrate a high level of consistency (translation < 40 mu m; rotation < 0.05 degrees) for d etected motion parameters. In vivo experiments were carried out and they sh owed a significant decrease of variance between successively acquired datas ets compared to retrospective correction algorithms. (C) 2000 Wiley-Liss, I nc.