Is colour Doppler sonography a good method to differentiate normal and abnormal appendices in children?

Aim

To determine whether colour Doppler sonograms can be used to differentiate between the normal appendix and acute appendicitis.

Material and methods

This prospective study examined 50 consecutive children with suspected appendicitis using grey-scale and colour Doppler US. Appendicitis was diagnosed when the appendix diameter was greater than 6mm. Blood flow on the appendiceal wall was measured and classified as non-existent (0 pixels), low (1–2), moderate (3–4) or abundant (>4). Likelihood ratios were calculated for each of these levels. The diagnosis of acute appendicitis was confirmed by pathological findings, and ruled out by clinical follow-up or pathological findings.

Results

Of the 50 patients examined, 24 had appendicitis and 26 had a normal appendix. For 25 of the patients with a normal appendix, appendicitis was ruled out by clinical follow-up, and for one patient, by pathological findings. The abnormal appendix was identified in all patients with appendicitis. In the group of 26 patients without appendicitis, the normal appendix was visualized in 23 cases, one of which was false positive (100% sensitivity, 96% specificity). Abnormal appendices showed moderate to abundant flow in 62% of the cases and non-existent or low flow in 38%. Normal appendices had non-existent or low flow in 82% of the cases, but moderate or abundant in 18%. Significant differences were only found when the number of pixels was >4.

Conclusion

Although the vascularity of normal and inflamed appendices may be different, this difference was not a good diagnostic indicator of appendicitis.