CT Findings that Indicate Pediatric Appendicitis: Lessons from Negative Appendectomies

Abstract

Purpose: Abdominal computed tomography (ACT) is widely used to diagnose appendicitis in children. Despite its high sensitivity and specificity, “negative appendectomies” still occur when the patient undergoes surgery but the final pathologic diagnosis does not support appendicitis. The aim of this study is to determine which findings support true appendicitis in patients with unclear findings on preoperative ACT. Methods: We performed a retrospective review of the records of 620 pediatric patients who underwent surgery for acute appendicitis between January 1, 2007 and December 31, 2020. We re-reviewed the scans in 101 patients who were deemed to have unclear preoperative findings on ACT, looking for the following features: periappendiceal fat infiltration, periappendiceal fluid collection, appendiceal wall thickening, appendiceal gas, and right lower quadrant lymphadenopathy. We then compared the presence of these features between patients with true appendicitis and those who underwent negative appendectomy. Results: The presence of an enlarged appendix, with a maximum diameter of more than 8 mm, and the presence of periappendiceal fat infiltration were associated with true appendicitis. Conclusion: If ACT findings are unclear in a patient with suspected acute appendicitis, the presence of an enlarged appendix and periappendiceal fat infiltration should be assessed to differentiate those with true appendicitis.