An Imaging Diagnostic Protocol in Children with Clinically Suspected Acute Appendicitis.

The objective of the present study is to evaluate a new diagnostic strategy using clinical findings followed by ultrasound (US) and, in selected cases, MRI. This study included 166 children presenting signs and symptoms suggesting acute appendicitis. Cases classified as suggesting appendicitis according to clinical exams had to be referred to surgery, whereas the other cases were discharged. Unclear cases were evaluated using US. If the US results were considered inconclusive, patients underwent MRI. Of the 166 patients, 78 (47%) had acute appendicitis and 88 (53%) had other diseases. The strategy under study had a sensitivity of 96 per cent, specificity of 100 per cent, positive predictive value of 100 per cent, negative predictive value of 97 per cent, and accuracy of 98 per cent. Eight patients remained undiagnosed and underwent MRI. After MRI two girls presented normal appendixes and were discharged. One girl had an enlarged appendix on MRI and appendicitis could have been confirmed by surgery. In the other five patients, no other sign of the disease was detected by MRI such as an inflammatory mass, free fluid or an abscess in the right iliac fossa. All of them were discharged after clinical observation. In the vast majority of cases the correct diagnosis was reached by clinical and US examinations. When clinical assessment and US findings were inconclusive, MRI was useful to detect normal and abnormal appendixes and valuable to rule out other abdominal pathologies that mimic appendicitis.