Computed tomography scan usage when US results are non-diagnostic for suspected acute appendicitis in children

This retrospective study was aimed to determine the factors suggesting the need for computed tomography (CT) scanning when ultrasound (US) imaging results are negative or non-diagnostic in children suspicious for acute appendicitis in the emergency department. Patients less than 18 years old who underwent abdominal ultrasound and CT to rule out acute appendicitis were enrolled. Patients were classified into 2 groups: the false-negative group, in which patients had negative or non-diagnostic results on the initial US and a final diagnosis of acute appendicitis on the following abdominal CT, and the true-negative group, in which patients had negative or non-diagnostic US results and were negative on abdominal CT. Logistic regression and propensity score matching with the predicting factors were performed. The presence of vomiting (odds ratio (OR), 7.78; 95% confidence interval (CI), 1.92–41.04) and poor oral intake (OR, 4.67; 95% CI, 1.21–21.15) with a high white blood cell (WBC) count (OR 1.26; 95% CI, 1.09–2.37), segmented neutrophil ratio (OR, 1.09; 95% CI, 1.03–1.16), and C-reactive protein (CRP) (OR, 1.49; 95% CI, 1.09–2.37) were suggestive of the false-negative group. The propensity-matched population also showed significant associations with vomiting (OR, 7.86; 95% CI, 1.65–37.40) and poor oral intake (OR, 5.50; 95% CI, 1.28–23.69) with an elevated WBC count (OR, 1.27; 95% CI, 1.08–1.50), segmented neutrophil ratio (OR, 1.09; 95% CI, 1.03–1.16), and CRP (OR, 1.51; 95% CI, 1.03–2.22). A CT scan should be considered in children with suspected acute appendicitis if they have vomiting, high CRP, and high WBC count, despite negative or non-diagnostic US results.