Decoupled automated rotational and translational registration for functional MRI time series data: the DART registration algorithm.
A rapid, in-plane image registration algorithm that accurately estimates and corrects for rotational and translational motion is described. This automated, one-pass method achieves its computational efficiency by decoupling the estimation of rotation and translation, allowing the application of rapid cross-correlation and cross-spectrum techniques for the determination of displacement parameters. k-space regridding and modulation techniques are used for image correction as alternatives to linear interpolation. The performance of this method was analyzed with simulations and echo-planar image data from both phantoms and human subjects. The processing time for image registration on a Hewlett-Packard 735/125 is 7.5 s for a 128 x 128 pixel image and 1.7 s for a 64 x 64 pixel image. Imaging phantom data demonstrate the accuracy of the method (mean rotational error, -0.09 degrees; standard deviation = 0.17 degrees; range, -0.44 degrees to +0.31 degrees; mean translational error = -0.035 pixels; standard deviation = 0.054 pixels; range, -0.16 to +0.06 pixels). Registered human functional imaging data demonstrate a significant reduction in motion artifacts such as linear trends in pixel time series and activation artifacts due to stimulus-correlated motion. The advantages of this technique are its noniterative one-pass nature, the reduction in image degradation as compared to previous methods, and the speed of computation.
Maas
L C
LC
Brain Imaging Center, McLean Hospital, Belmont, Massachusetts 02178, USA.
Frederick
B D
BD
Renshaw
P F
PF
D000328:Adult; D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D017352:Echo-Planar Imaging / Q000379:methods*; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted