Image-based method for retrospective correction of physiological motion effects in fMRI: RETROICOR.
Respiration effects and cardiac pulsatility can induce signal modulations in functional MR image time series that increase noise and degrade the statistical significance of activation signals. A simple image-based correction method is described that does not have the limitations of k-space methods that preclude high spatial frequency correction. Low-order Fourier series are fit to the image data based on time of each image acquisition relative to the phase of the cardiac and respiratory cycles, monitored using a photoplethysmograph and pneumatic belt, respectively. The RETROICOR method is demonstrated using resting-state experiments on three subjects and compared with the k-space method. The method is found to perform well for both respiration- and cardiac-induced noise without imposing spatial filtering on the correction. Magn Reson Med 44:162-167, 2000.
Glover
G H
GH
Department of Radiology, Stanford University School of Medicine, Center for Advanced MR Technology at Stanford, Stanford, California, USA. gary@s-word.stanford.edu
Li
T Q
TQ
Ress
D
D
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006321:Heart / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009068:Movement / Q000502:physiology; D012143:Respiratory Physiological Phenomena