Comparison of Ultrasound and Computed Tomography Scanning Accuracy in Diagnosing Acute Appendicitis at King Abdulaziz University Hospital

Background: Choosing the most effective and accurate preoperative modality is one of the most significant tools in the clinical diagnosis of acute appendicitis (AA) to prevent negative appendectomies, diagnosis confusion, and delayed treatment. This decision making remains challenging to emergency physicians and surgeons which lead this study to determine the sensitivity and specificity of ultrasound (US) and computed tomography (CT) in predicting AA using pathology reports as a reference at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. Methods: This study was conducted retrospectively at the Emergency Department, KAUH in Jeddah, Saudi, Arabia using 351 medical records with a clinical picture of acute appendicitis and no history of trauma. The sensitivity and specificity were calculated for ultrasound and computed tomography imaging. The positive predictive values (PPV) and negative predictive value (NPV) were also evaluated. Results: Out of the total 351 patients included in this study, 83 patients underwent surgical appendectomies and the pathology results revealed that 64 patients were diagnosed with AA while 19 showed a normal appendix. Of the 64 patients, 18 underwent US imaging while 62 underwent CT imaging. Compared to pathology results, US imaging results revealed that 12 out of 14 positive patients (85.7%) and only two out of four negative patients (50.0%) were correctly predicted while two out of 14 positive patients (14.3%) and two out of four negative patients (50.0%) were falsely diagnosed. On the other hand, CT imaging results revealed that 46 out of 49 positive patients (93.9%) and 9 out of 13 negative patients (69.2%) were correctly predicted while only three out of 49 positive patients (6.1%) and only four out of 13 negative patients (30.8%) were incorrectly diagnosed. Conclusion: Having an accuracy of 88.71%, sensitivity of 92.00%, and specificity of 75.00%, CT imaging was found to be more effective and accurate than US imaging which was only 77.78% accurate, 85.71% sensitive, and 50.00% specific. Statistical analyses also revealed that US results have a significant difference with pathology results (P= 0.130) while CT result has no significant difference (P <0.001).