Quantitative diffusion-weighted magnetic resonance enterography in ileal Crohn's disease: A systematic analysis of intra and interobserver reproducibility

Table 3 Interobserver agreement and variability of apparent diffusion coefficient and signal ratio measurements between the two readers over two sessions

Group	CD (n = 21)							Normal (n = 23)
	1st session reader 1	1st session reader 2	P-value	2nd session reader 1	2nd session reader 2	P-value		1st session reader 1	1st session reader 2		P-value	2nd session reader 1	2nd session reader 2	P-value
ADC	1.50 ± 0.40	1.52 ± 0.45	0.402	1.54 ± 0.45	1.56 ± 0.47	0.379		2.55 ± 0.53	2.57 ± 0.50		0.815	2.53 ± 0.53	2.64 ± 0.57	0.208
ICC	0.969			0.984				0.641				0.736
CoV	4.71			3.73				11.43				11.07
Bias (%)	-0.72			-0.82				-1.20				-3.98
LoA (%)	-14.29 to 12.85			-12.09 to 10.44				-32.03 to 29.62				-33.93 to 25.96
SR	4.17 ± 1.43	4.21 ± 1.34	0.473	4.20 ± 1.36	4.23 ± 1.42		0.569	1.45 ± 0.54		1.44 ± 0.52	0.760	1.44 ± 0.53	1.45 ± 0.56	0.618
ICC	0.981			0.989				0.950				0.971
CoV	4.53			3.72				8.12				6.27
Bias (%)	-1.85			-0.39				0.43				-0.59
LoA (%)	-17.30 to 13.60			-12.38 to 11.61				-22.17 to 23.04				-19.47 to 18.29

Apparent diffusion coefficient (ADC) and signal ratio parameters are expressed as the mean ± standard deviation, ADC units: ×10^-3 mm²/s. ADC: Apparent diffusion coefficient; SR: Signal ratio; CD: Crohn’s disease; ICC: Intraclass correlation coefficient; CoV: Coefficients of variation; LoA: Bland-Altman analysis with 95% limits of agreement.