[Diagnostic role of echography in acute appendicitis in children].

Eighty-seven pediatric patients with suspected acute appendicitis underwent high-resolution US with graded abdominal compression. The study was limited to the patients with a questionable clinical diagnosis, accounting for about 40% of the patients examined for acute appendicitis in our Institution. US had 87.3% accuracy, 81.5% sensitivity, and 90% specificity. The main US findings in the positive cases were: visualization of the appendix as a tubular non-compressible structure, with a diameter of 5 mm or more, symmetric/asymmetric wall thickening, possible presence of appendicoliths and variable appearance of the central echogenic layer (preserved, doubled for lumen dilatation, partially/totally lost). The above US findings were grouped in 3 basic patterns: type I (thickened appendix with no structural abnormalities) appeared to be related to non-suppurative and phlegmonous acute appendicitis; type II (detectable appendiceal abnormalities) was observed both in phlegmonous and in suppurative acute appendicitis; type III (pericecal complex mass, frequently with appendicoliths) was found in all cases of periappendiceal abscess. In our experience, the use of US in the diagnosis of acute appendicitis in children allowed a reduction by about 2/3 in the rate of unnecessary laparotomies. Such a finding emerges from the comparison with the results obtained in the 2 years prior to the use of US. The technique also allowed an unquestionable diagnosis of acute appendicitis or periappendiceal abscess to be made in a number of clinically equivocal cases, thus avoiding potentially harmful delays in diagnosis. On the other hand, the incidence of false-negatives on US is not negligible, which calls for a cautious clinical and US evaluation of all equivocal cases following no typical US pattern.