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Abstract #3432

Scan-To-Scan Unwarping of Residual Distortions in Prospectively Motion Corrected EPI Time Series

Benedikt Andreas Poser1, Kazim Gumus1, Brian Robert Keating1, Brian Armstrong2, Todd P. Kusik2, Julian Maclaren3, Thomas E. Prieto4, Oliver Speck5, Maxim Zaitsev3

1UH-QMC Neuroscience and MR Research Program, University of Hawaii, Honolulu, HI, United States; 2Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, United States; 3Magnetic Resonance Development and Application Center, University Hospital Freiburg, Germany; 4Medical College Wisconsin, United States; 5Dept Biomedical Magnetic Resonance, Otto-von-Guericke-University, Magdeburg, Germany

fMRI data quality critically depends on subject motion. In EPI, its leads to head pose dependent distortions that cannot be corrected by post-hoc image realignment and hamper the detection of task activation. Prospective motion correction approaches have been developed to track head position in real-time and continuously update slice positions during the scan. However, changes in absolute head orientation relative to B0 may alter the field distribution and hence EPI image distortions. To address this concern, we explored a dynamic distortion correction approach. We used IDEA EPI (interleaved dual echo with acceleration EPI) which allows field maps to be extracted from and applied to every fMRI volume, combined with real-time motion correction by means of an retro-grade-reflector (MPT) based tracking system.