Quantitative Elastography for Cervical Stiffness Assessment during Pregnancy

Table 2

Reliability of tissue strain measurement.

	ICC consistency	ICC agreement	MD	SD	D/M of TS
Reliability of strain calculation
Intraobserver (Ff^1/Ff^1)	0.97 (0.95/0.98)	0.97 (0.95/0.98)	−0.005 (−0.015/0.006)	0.047	7% (5–8%)
Interobserver (Ff^1/Sf^1)	0.98 (0.97/0.99)	0.98 (0.97/0.99)	−0.007 (−0.017/0.002)	0.041	5% (4–6%)
Interobserver (Fs^1/Ss^1)	0.99 (0.99/1.00)	0.99 (0.99/1.00)	−0.001 (−0.007/0.004)	0.023	3% (3-4%)
Interobserver (Ff^1/Sf^1; and Fs^1/Ss^1)	0.99 (0.98/0.99)	0.99 (0.98/0.99)	−0.004 (−0.010/0.001)	0.033	4% (3–5%)
Reliability of raw data acquirement
Interobserver (Ff^1/Fs^1)	0.89 (0.84/0.93)	0.89 (0.82/0.93)	−0.029 (−0.050/−0.007)	0.092	12% (9–15%)
Interobserver (Sf^1/Ss^1)	0.91 (0.86/0.94)	0.91 (0.85/0.94)	−0.020 (−0.040/0.000)	0.084	10% (8–13%)
Interobserver (Ff^1/Fs^1; and Sf^1/Ss^1)	0.90 (0.86/0.93)	0.89 (0.85/0.92)	−0.024 (−0.038/−0.009)	0.089	11% (10–13%)
Reliability of raw data acquirement and strain calculation
Intraobserver (Ff^1/Ff^2)	0.93 (0.89/0.96)	0.93 (0.90/0.96)	0.002 (−0.015/0.019)	0.072	10% (8–13%)
Interobserver (Ff^1/Ss^1)	0.90 (0.85/0.94)	0.89 (0.82/0.93)	−0.029 (−0.050/−0.008)	0.088	12% (9–14%)
Interobserver; (Ff^1Ff^2/Ss^1—average of 2; raw data)	0.93 (0.89/0.96)	0.93 (0.89/0.96)	0.001 (−0.016/0.018)	0.072	10% (8–13%)

Reproducibility of tissue strain measurement, including raw data acquirement and tissue strain (TS) calculation. In brackets the 95% confidence interval is reported. MD: mean of differences; SD: standard deviation of MD; D/M of TS (= percentage difference): difference between TS values/mean of TS values (mean value and CI95).