Table 2. Intra-observer and inter-observer variability.

		Small nodules		Large nodules
		p-value	pc-value	p-value	pc-value
FBP	Observer 1–1 vs observer 1–2	0.068	0.98	0.317	0.99
	Observer 1–1 vs observer 2	0.075	0.98	0.317	0.99
	Observer 1–2 vs observer 2	0.854	1.00	0.317	1.00
iDose4 L2	Observer 1–1 vs observer 1–2	0.655	1.00	0.655	1.00
	Observer 1–1 vs observer 2	0.465	1.00	0.317	1.00
	Observer 1–2 vs observer 2	0.593	1.00	0.285	1.00
iDose4 L4	Observer 1–1 vs observer 1–2	0.080	0.99	1.000	1.00
	Observer 1–1 vs observer 2	0.109	1.00	0.180	1.00
	Observer 1–2 vs observer 2	0.285	1.00	0.180	1.00
iDose4 L6	Observer 1–1 vs observer 1–2	0.500	0.99	0.317	1.00
	Observer 1–1 vs observer 2	0.463	0.99	0.317	1.00
	Observer 1–2 vs observer 2	0.893	1.00	1.000	1.00

P-values and concordance correlation coefficients (p_c-values) of measured pulmonary nodule volumes using filtered back projection (FBP) and iterative reconstruction (iDose⁴ level 2, 4 and 6) by two observers.

p-value Based on Wilcoxon signed ranks test; p_c-value Concordance correlation coefficient; FBP Filtered back projection; L2 Level 2; L4 Level 4; L6 Level 6; Observer 1–1 First measurement by first observer; Observer 1–2 Second measurement by first observer; Observer 2 Measurement by second observer.