Table 3 Diagnostic value of magnetic resonance colonography on a patient basis.
| <5 mm (group a) | 5–10 mm (group b) | >10 mm (group c) | >5 mm (groups b+c) | All | |
|---|---|---|---|---|---|
| No (C) | 56 | 45 | 20 | 52 | 121 |
| No (MRC) | 3 | 27 | 14 | 33 | 44 |
| Sensitivity (%) | 5.4 | 60.0 | 70.0 | 63.5 | 36.4 |
| Specificity (%) | 95.0 | 97.8 | 100 | 97.9 | 90.2 |
| NPV (%) | 82.3 | 93.6 | 98.0 | 93.1 | 69.4 |
| PPV (%) | 18.8 | 81.8 | 100.0 | 84.6 | 69.8 |
| Accuracy (%) | 79.0 | 92.4 | 98.1 | 92.1 | 69.5 |
| False positive findings of MRC | 13 | 6 | 0 | 6 | 19 |
C, colonoscopy; MRC, magnetic resonance colonography; NPV, negative predictive value; PPV, positive predictive value.
Note: If multiple lesions of different sizes were found in a patient, the patient group was ranked depending on the largest lesion. If MRC showed both false positive and positive findings in a patient, the patient group was ranked according to the positive findings.