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Reverse retrospective motion correction
Author(s) -
Zahneisen Benjamin,
Keating Brian,
Singh Aditya,
Herbst Michael,
Ernst Thomas
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25830
Subject(s) - imaging phantom , computer science , acceleration , image quality , iterative reconstruction , computer vision , artificial intelligence , undo , artifact (error) , algorithm , image (mathematics) , nuclear medicine , physics , medicine , classical mechanics , operating system
Purpose One potential barrier for using prospective motion correction (PMC) in the clinic is the unpredictable nature of a scan because of the direct interference with the imaging sequence. We demonstrate that a second set of “de‐corrected” images can be reconstructed from a scan with PMC that show how images would have appeared without PMC enabled. Theory and Methods For three‐dimensional scans, the effects of PMC can be undone by performing a retrospective reconstruction based on the inverse of the transformation matrix used for real time gradient feedback. Retrospective reconstruction is performed using a generalized SENSE approach with continuous head motion monitored using a single‐marker optical camera system. Results Reverse retrospective reconstruction is demonstrated for phantom and in vivo scans using an magnetization‐prepared rapid gradient echo (MPRAGE) sequence including parallel and Partial Fourier acceleration. Conclusion Reverse retrospective reconstruction can almost perfectly undo the effects of prospective feedback, and thereby provide a second image data set with the effects of motion correction removed. In case of correct feedback, one can directly compare the quality of the corrected with that of the uncorrected scan. Additionally, because erroneous feedback during PMC may introduce artifacts, it is possible to eliminate artifacts in a corrupted scan by reversing the false gradient updates. Magn Reson Med 75:2341–2349, 2016. © 2015 Wiley Periodicals, Inc.