Table 2.
Interobserver agreement of MRI feature classification*
| Feature | N | Agreement Rate | Kappa (UW, Observed) | Kappa (max) |
|---|---|---|---|---|
| Tumor extension beyond pons/BP | 30 | 0.830 | 0.210 | 0.526 |
| Tumor extension (raw) | 30 | 0.330 | NA | NA |
| Tumor margins (well vs ill-defined) | 30 | 0.800 | NA | NA |
| Tumor location (central vs eccentric) | 30 | 0.930 | 0.634 | 0.634 |
| Tumor extent (contained vs exophytic) | 30 | 0.767 | 0.420 | 0.420 |
| Tumor signal (T1/T2) | 30 | 1.000 | 1.000 | 1.000 |
| T2 hypointensity | 30 | 0.533 | 0.110 | 0.237 |
| Diffusion restriction | 18 | 0.778 | 0.517 | 0.753 |
| Heterogeneity (any) | 30 | 1.000 | 1.000 | 1.000 |
| Heterogeneity (raw) | 30 | 0.667 | NA | NA |
| Hemorrhage | 30 | 0.933 | 0.634 | 0.634 |
| Enhancement (yes vs no) | 29 | 0.897 | 0.731 | 0.910 |
| Enhancement pattern | 29 | 0.758 | 0.638 | 0.774 |
| Necrosis | 30 | 0.933 | 0.864 | 1.000 |
| Spectroscopy Cho elevation | 7 | 0.570 | NA | NA |
| Spectroscopy reduced NAA | 7 | 0.860 | NA | NA |
| Spectroscopy lactate | 7 | 0.860 | NA | NA |
| Hydrocephalus | 30 | 0.967 | 0.911 | 0.911 |
| Non-DIPG | 30 | 0.967 | NA | NA |
| Mean (dichotomized) | 0.838 | 0.622 | 0.733 |
*NA: some cell numbers too few for kappa calculation.