Boxplots of displacements of the dwell positions from catheter-based registration (a) and from marker-based registration (b). The shifts are shown as absolute vector lengths (abs) and for the three separate directions (L-R, C-C and D-V). For C-C, a positive value indicates a caudal shift; for D-V, a positive value indicates a ventral shift. The dotted horizontal line represents no displacement. The crosses represent outliers.