Optimizing US examination to detect the normal and abnormal appendix in children

Background: US detection of a normal appendix can safely rule out appendicitis. However, there is a wide range of accuracy in detection of a normal appendix. Objective: To optimize US examination to detect the normal and the abnormal appendix according to the potential positions of the appendix. Materials and methods: This prospective study included 107 children who underwent gray-scale US scanning. Noncompressive and compressive graded sonography was performed to detect normal and abnormal appendices according to their potential positions. The maximum transverse diameter of the appendices was measured. Results: Of the 107 children examined, 56 had a histologic diagnosis of acute appendicitis. Sonography had a sensitivity of 100% and specificity of 98% for the diagnosis of appendicitis. A normal appendix was visualized in 44 (86.2%) of the 51 patients without acute appendicitis, and of these 44, 43 were true-negative and 1 was false-positive. Normal and abnormal appendices, respectively, were positioned as follows: 54.4% and 39.3% were mid-pelvic; 27.2% and 28.6% were retrocecal; 11.4% and 17.8% were deep pelvic; and 6.8% and 14.3% were abdominal. Conclusion: US scanning according to the potential positions of the appendix was useful in the detection of normal appendices in children suspected of having appendicitis.