Table 3.
Performance of patient-averaged values of individual feature changes to separate RP patients from non-RP patients
| AUC | ||||
|---|---|---|---|---|
| Feature/dose-dependent measurement | Low dose | Medium dose | High dose | Fitted slope |
| First-order features | ||||
| 70% Quantile*,† | 0.72 | 0.77 | 0.77 | 0.77 |
| Median*,† | 0.70 | 0.73 | 0.75 | 0.75 |
| Mean*,† | 0.68 | 0.73 | 0.75 | 0.76 |
| Binned entropy* | 0.68 | 0.74 | 0.75 | 0.68 |
| 30% quantile* | 0.67 | 0.69 | 0.72 | 0.74 |
| Unbinned entropy | 0.66 | 0.69 | 0.71 | 0.69 |
| 5% Quantile | 0.61 | 0.62 | 0.65 | 0.69 |
| Minimum | 0.58 | 0.56 | 0.63 | 0.58 |
| Fractal features | ||||
| Brownian dimension* | 0.66 | 0.72 | 0.78 | 0.78 |
| Box-counting dimension | 0.49 | 0.54 | 0.60 | 0.67 |
| Fine box-counting dimension | 0.49 | 0.49 | 0.52 | 0.54 |
| Laws’ filter features | ||||
| E5L5 entropy* | 0.63 | 0.72 | 0.75 | 0.77 |
| R5L5 entropy* | 0.63 | 0.73 | 0.75 | 0.77 |
| S5L5 entropy* | 0.62 | 0.71 | 0.74 | 0.76 |
| W5L5 entropy* | 0.62 | 0.71 | 0.73 | 0.76 |
| GLCM features | ||||
| Sum average*,† | 0.69 | 0.74 | 0.76 | 0.77 |
| Sum of squares variance*,† | 0.70 | 0.75 | 0.76 | 0.77 |
| Sum entropy | 0.68 | 0.70 | 0.73 | 0.68 |
| Difference entropy | 0.62 | 0.65 | 0.68 | 0.66 |
| Entropy | 0.59 | 0.60 | 0.60 | 0.50 |
| Average AUC across features | 0.64 | 0.68 | 0.71 | 0.71 |
Abbreviations AUC = Area under the receiver operating characteristic curve; E5L5 = edge-level filter; GLCM = gray-level co-occurrence; RP = radiation pneumonitis; R5L5 = ripple-level filter; S5L5 = spot-level filter; W5L5 = wave-level filter.
*
Significant (P<0.0025) relationship between change in feature value (ΔFV) and grade ≥2 RP.
†
Significant (P<0.0025) relationship between DFV and grade ≥3 RP.