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

Table 1 Clinical characteristics of included subjects

Characteristic	Value
CD patients (n)	21
Age (yr) (mean ± SD)	43.4 ± 16.1
Gender (males: Females)	11:10
CRP (mg/dL) [median (range)]	21.0 (0.9-94.0)
ESR (mm/h) [median (range)]	19 (7-51)
Days between MRE and endoscopy median [median (range)]	4 (0-7)
Endoscopic findings of terminal ileum (n)
Overt ulcers	12
Aphthoid lesions	5
Erythema or edema conditions	4
Control group (n)	23
Age (yr) (mean ± SD)	46.3 ± 15.4
Gender (males:females)	11:12
Days between MRE and endoscopy [median (range)]	3 (1-7)
Total (n)	44
Age (yr) (mean ± SD)	44.9 ± 15.7
Gender (males:females)	22:22
Days between MRE and endoscopy [median (range)]	4 (0-7)

CD: Crohn’s disease; SD: Standard deviation; CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate; MRE: Magnetic resonance enterography.

Table 2 Intraobserver 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	2nd session reader 1	P-value	1st session reader 2	2nd session reader 2	P-value	1st session reader 1	2nd session reader 1	P-value	1st session reader 2	2nd session reader 2	P-value
ADC	1.50 ± 0.40	1.54 ± 0.45	0.201	1.52 ± 0.45	1.56 ± 0.47	0.125	2.55 ± 0.53	2.53 ± 0.53	0.772	2.57 ± 0.50	2.64 ± 0.57	0.450
ICC	0.952			0.977			0.736			0.711
CoV	6.28			4.71			10.47			10.64
Bias (%)	1.77			1.89			-1.07			-1.71
LoA (%)	-14.10 to 17.65			-10.65 to 14.42			-30.75 to 28.62			-28.30 to 24.86
SR	4.17 ± 1.43	4.20 ± 1.36	0.505	4.21 ± 1.34	4.23 ± 1.42	0.794	1.45 ± 0.54	1.44 ± 0.53	0.697	1.44 ± 0.52	1.45 ± 0.56	0.704
ICC	0.989			0.979			0.974			0.944
CoV	3.51			4.64			5.93			8.69
Bias (%)	1.39			-0.07			-0.58			0.45
LoA (%)	-9.22 to 12.01			-13.81 to 13.67			-19.16 to 17.99			-23.99 to 24.88

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.

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.

Table 4 Diagnostic performance of apparent diffusion coefficient and signal ratio for differentiating inflammatory lesions from normal terminal ileum

	CD (n = 21)	Normal (n = 23)	P-value	Cut-off value	AUROC	Sensitivity (%)	Specificity (%)
First reader
ADC value	1.52 ± 0.42	2.54 ± 0.49	< 0.001a	1.80	0.923	85.7	95.7
SR value	4.19 ± 1.39	1.44 ± 0.53	< 0.001a	2.24	0.981	90.5	95.7
Second reader
ADC value	1.54 ± 0.46	2.61 ± 0.48	< 0.001a	1.81	0.929	85.7	95.7
SR value	4.22 ± 1.37	1.45 ± 0.53	< 0.001a	2.07	0.988	95.2	95.7

^aP < 0.05 was considered statistically significant. Apparent diffusion coefficient (ADC) and signal ratio parameters are expressed as the mean ± SD, ADC units: ×10^-3 mm²/s. ADC: Apparent diffusion coefficient; SR: Signal ratio; CD: Crohn’s disease; AUROC: Areas under receiver operating characteristic curve.