Motion Correction for DWI with Segmented EPI: Comparison Between an Iterative Parameter Space Searching Technique and Conventional Navigator Echo Correction

J. D. Winter, N. Gelman, R. T. Thompson Lawson Health Research Institute, London, Ontario, Canada, Medical Biophysics, University of Western Ontario, London, Ontario, Canada Introduction: Multi-segment diffusion-weighted imaging (DWI) techniques are inherently sensitive to patient movement because of inter segment phase differences generated by motion occurring during the large diffusion gradients. Navigator echo correction techniques attempt to measure these phase differences for each segment with projections or low-resolution images and use this phase information to correct the images. An alternative approach is to use an iterative parameter space search to determine the optimal phase difference parameters for each segment. (These parameters are the 0 order phase, 1 order phases along the x and y directions). Previously the performance of this technique was qualitatively assessed based on its application on moderately (b = 350 mm/s) diffusion-weighted images acquired from a single subject using two and four segment interleaved segmented EPI. The objective of the present work was to provide a quantitative assessment of the performance of this method in comparison to the 1D navigator echo motion correction method. The comparison is carried out using DWI (b = 600 mm/s) from 8 adults and 5 neonates.