Performance of specific X-ray imaging signs for the diagnosis of intestinal perforation
| Variable | Sensitivity (%) | Specificity (%) | Accuracy (%） |
| Lucency over the liver shadow | 64.60 | 100 | 93.31 |
| Falciform ligament sign | 45.13 | 100 | 89.63 |
| Football sign | 37.17 | 100 | 88.13 |
| Rigler sign | 30.97 | 100 | 86.96 |
| Triangle sign | 15.93 | 100 | 18.81 |
| More than one of the above signs | 86.73 | 100 | 97.49 |