Comparison between computed tomography and ultrasonography to diagnose acute appendicitis in a Saudi population

Background/Aim: One of the most common emergency department (ED) presentations and pediatric abdominal surgery causes is acute appendicitis. Imaging is crucial to management since clinical evaluation might be erroneous. The aim of this study was to evaluate the accuracy of computed tomography (CT) compared with ultrasonography (US) in the diagnosis of acute appendicitis in a Saudi population. In addition, the study sought to evaluate the improvement of diagnostic accuracy when a complementary CT is added after inconclusive results of US. Methods: Retrospective study involved 225 patients who were referred from the ED and underwent diagnostic US and/or CT for possible acute appendicitis. Of these 225 patients, US was performed for 82, CT for 83, and both US and CT for 60 patients, before surgery. Results: Accuracy of CT (84.33%) was higher than US (56.09%). Specificity and negative predictive value (NPV) of US were higher than CT. In contrast, sensitivity, positive predictive value (PPV), and accuracy were better for CT than US. For patients who underwent both US and CT, receiver operating characteristic (ROC) analysis demonstrated that US sensitivity was 70% and specificity was 63.2% and CT sensitivity was 75.3% and specificity was 80.1%. Conclusion: Although CT is more accurate and sensitive than US for diagnosing acute appendicitis, US can still be used as the primary imaging modality due to its high specificity. In turn, CT may be reserved for the patients who have a clinical diagnosis of acute appendicitis and negative US results. This approach may reduce the radiation exposure to ∼50% of patients presenting with acute appendicitis in the ED