Table 3.
Sensitivity, specificity, positive (PPV) and negative (NPV) predictive value of conventional bowel US and contrast enhanced bowel US in detecting one or more small bowel strictures as identified at barium x ray
| TP | TN | FP | FN | Sensitivity (95% CI) | Specificity (95% CI) | PPV | NPV | |
| Conventional bowel US | ||||||||
| At least one small bowel stricture* | 20 | 70 | 5 | 7 | 74.0% (72.1–75.8) | 93.3% (90.9–95.6) | 80.0% | 90.9% |
| Multiple strictures (two or more) | 5 | 86 | 5 | 4 | 55.5% (54.1–56.8) | 95.5% (93.1–97.8) | 50.0% | 95.5% |
| Contrast enhanced US | ||||||||
| At least one small bowel stricture* | 24 | 73 | 2 | 3 | 88.8% (86.5–91.0) | 97.3% (94.8–99.7) | 92.3% | 96.0% |
| Multiple strictures (two or more) | 7 | 89 | 2 | 2 | 77.7% (75.7–79.6) | 97.8% (95.3–100) | 77.7% | 97.8% |
TP, true positive; TN, true negative; FP, false positive; FN, false negative.
*In this analysis a result was considered to be truly positive when at least one stricture, identified at US, was matched to a lesion seen at small bowel enteroclysis. In other words, each patient was classified simply as a carrier of small bowel stenosis if at least one of these lesions was revealed at x ray.