Table 2.
Test–retest reliability of the three measurement methods among the four observers.
| Level | Measurement method | Observer 1 ICC(95% CI) |
Observer 2 ICC(95% CI) |
Observer 3 ICC(95% CI) |
Observer 4 ICC(95% CI) |
|---|---|---|---|---|---|
| C1/2 | Mean ROI | 0.460 (0.149–0.688) | 0.558 (0.275–0.752) | 0.986 (0.973–0.993) | 0.995 (0.990–0.997) |
| Manual ROI | 0.541 (0.253–0.741) | 0.524 (0.230–0.730) | 0.969 (0.940–0.985) | 0.997 (0.9932–0.998) | |
| Sagittal ROI | 0.810 (0.653–0.901) | 0.684 (0.453–0.828) | 0.889 (0.790–0.943) | 0.645 (0.396–0.805) | |
| C2/3 | Mean ROI | 0.892 (0.794–0.944) | 0.919 (0.845–0.959) | 0.977 (0.955–0.987) | 0.992 (0.985–0.996) |
| Manual ROI | 0.798 (0.632–0.894) | 0.888 (0.788–0.943) | 0.944 (0.891–0.972) | 0.993 (0.986–0.996) | |
| Sagittal ROI | 0.646 (0.398–0.806) | 0.816 (0.663–0.904) | 0.926 (0.856–0.962) | 0.973 (0.948–0.987) | |
| C3/4 | Mean ROI | 0.948 (0.898–0.974) | 0.843 (0.709–0.919) | 0.991 (0.982–0.996) | 0.992 (0.983–0.996) |
| Manual ROI | 0.914 (0.834–0.956) | 0.868 (0.753–0.932) | 0.989 (0.978–0.995) | 0.984 (0.968–0.992) | |
| Sagittal ROI | 0.891 (0.794–0.944) | 0.942 (0.886–0.970) | 0.913 (0.834–0.956) | 0.965 (0.931–0.982) | |
| C4/5 | Mean ROI | 0.910 (0.828–0.954) | 0.959 (0.920–0.979) | 0.945 (0.894–0.972) | 0.994 (0.989–0.997) |
| Manual ROI | 0.923 (0.851–0.961) | 0.917 (0.840–0.957) | 0.984 (0.968–0.992) | 0.990 (0.980–0.995) | |
| Sagittal ROI | 0.797 (0.631–0.893) | 0.808 (0.650–0.899) | 0.865 (0.746–0.930) | 0.974 (0.949–0.987) | |
| C5/6 | Mean ROI | 0.635 (0.383–0.800) | 0.807 (0.647–0.899) | 0.964 (0.930–0.982) | 0.980 (0.961–0.990) |
| Manual ROI | 0.888 (0.788–0.943) | 0.783 (0.607–0.885) | 0.981 (0.963–0.991) | 0.994 (0.988–0.997) | |
| Sagittal ROI | 0.659 (0.418–0.814) | 0.840 (0.703–0.917) | 0.934 (0.872–0.966) | 0.887 (0.785–0.942) | |
| C6/7 | Mean ROI | 0.582 (0.308–0.767) | 0.813 (0.657–0.902) | 0.946 (0.895–0.973) | 0.990 (0.980–0.995) |
| Manual ROI | 0.660 (0.418–0.814) | 0.683 (0.452–0.828) | 0.966 (0.932–0.983) | 0.992 (0.984–0.996) | |
| Sagittal ROI | 0.518 (0.223–0.727) | 0.813 (0.658–0.902) | 0.924 (0.854–0.961) | 0.977 (0.955–0.989) | |
| C7/T1 | Mean ROI | 0.834 (0.692–0.913) | 0.735 (0.532–0.858) | 0.980 (0.961–0.990) | 0.995 (0.989–0.997) |
| Manual ROI | 0.814 (0.659–0.903) | 0.711 (0.494–0.844) | 0.972 (0.944–0.986) | 0.983 (0.966–0.992) | |
| Sagittal ROI | 0.798 (0.632–0.894) | 0.815 (0.661–0.903) | 0.919 (0.844–0.959) | 0.924 (0.854–0.961) |
Two elective medical university students (observers 1 and 2), one third-year radiology resident (observer 3), and one neuro-radiologist with 2 years of experience in diffusion tensor imaging (observer 4).
FA, fractional anisotropy, ICC, intraclass correlation coefficient, CI, confidence interval, ROI, region of interest.