Extrapolation-Based References Improve Motion and Eddy-Current Correction of High B-Value DWI Data: Application in Parkinson’s Disease Dementia
Fig 8
Effect of the registration error on tractography based on high b-value data.
Panel A shows the mean diffusivity map of a patient with atrophy. Panels B–D shows a zoomed in section, delineated in panel A. Point clouds in white represent a coronal cross section of the retrosplenial cingulum obtained from tractography using high b-value HARDI data. The tract points are overlaid on top of a colour FA-volume, which was calculated from data acquired with low b-values. When using data corrected with the conventional method (panel B), the point cloud appears in a region approximately two voxels above the expected region (green voxels). Data corrected with the CHARMED-based extrapolation method resulted in a point cloud slightly below the expected region (panel C). For data processed with the CSF-corrected extrapolation-based motion and eddy-current correction the point cloud corresponds well to the anatomical structure (panel D).