Table 3.

The effect of variability in SimCT slice thickness reconstruction on the performance of registration algorithms.

Registration Method	Metric	STR < 3 mm†		STR ≥ 3 mm‡		p-value
		Mean	SD	Mean	SD
Rigid	95%HD (mm)	15.7	12.4	14.4	11.5	0.25
	DSC	0.24	0.22	0.27	0.22	0.006*
Atlas-based	95%HD (mm)	7.2	10.6	7.7	11.2	<0.0001* §
	DSC	0.64	0.15	0.65	0.14	0.74
B-spline	95%HD (mm)	10.8	10.1	10.5	11.2	0.02*
	DSC	0.41	0.22	0.47	0.20	<0.0001*§
Demons	95%HD (mm)	14.3	12.2	13	11.6	0.17
	DSC	0.33	0.25	0.38	0.24	0.0019*§
Optical Flow	95%HD (mm)	16.1	13.2	14.3	11.1	0.14
	DSC	0.28	0.22	0.31	0.22	0.0034*§

^†n = 10 patients,

^‡n = 10 patients,

^*significant p<0.05 for Wilcoxon rank test,

^§significant p<0.005 after Bonferroni correction (α = 0.05/10 “pairwise comparison of 5 DIR algorithms”).

Abbreviations: STR=slice thickness reconstruction, DSC=Dice similarity coefficient, 95%HD=95%Hausdorff distance.