title: Real-time correction by optical tracking with integrated geometric distortion correction for reducing motion artifacts in functional MRI.
abstract: Head motion artifacts are a major problem in functional MRI that limit its use in neuroscience research and clinical settings. Real-time scan-plane correction by optical tracking has been shown to correct slice misalignment and nonlinear spin-history artifacts; however, residual artifacts due to dynamic magnetic field nonuniformity may remain in the data. A recently developed correction technique, Phase Labeling for Additional Coordinate Encoding, can correct for absolute geometric distortion using only the complex image data from two echo planar images with slightly shifted k-space trajectories. An approach is presented that integrates Phase Labeling for Additional Coordinate Encoding into a real-time scan-plane update system by optical tracking, applied to a tissue-equivalent phantom undergoing complex motion and an functional MRI finger tapping experiment with overt head motion to induce dynamic field nonuniformity. Experiments suggest that such integrated volume-by-volume corrections are very effective at artifact suppression, with potential to expand functional MRI applications.
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, Canada. djrotenberg@gmail.com
authors.forename: David
authors.initials: D
authors.lastname: Rotenberg
authors.forename: Mark
authors.initials: M
authors.lastname: Chiew
authors.forename: Shawn
authors.initials: S
authors.lastname: Ranieri
authors.forename: Fred
authors.initials: F
authors.lastname: Tam
authors.forename: Rajiv
authors.initials: R
authors.lastname: Chopra
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Graham
mesh_terms: D000328:Adult; D016477:Artifacts; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003199:Computer Systems; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D009038:Motion; D055096:Optical Devices; D010781:Photography / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018511:Systems Integration; D055815:Young Adult