Comparison of CT Protocols in Diagnosing Acute Appendicitis: A Systematic Review of Diagnostic Performance and Operational Efficiency

BackgroundComputed tomography (CT) is the preferred imaging modality for diagnosing acute appendicitis in adults. However, the optimal contrast protocol remains debated, balancing diagnostic accuracy, operational efficiency, and patient safety.ObjectiveTo systematically compare the diagnostic accuracy and operational efficiency of different CT contrast protocols-oral, intravenous (IV), combined oral + IV, and non-contrast-in adult patients with suspected acute appendicitis.MethodsA comprehensive search of MEDLINE, Embase, Cochrane Library, and Web of Science was conducted from inception to April 2025. Eligible studies compared CT contrast protocols in adults (≥18 years) and reported diagnostic or operational outcomes. Two independent reviewers screened articles, extracted data, and assessed risk of bias using the QUADAS-2 tool. Primary outcomes were sensitivity, specificity, positive predictive value, and negative predictive value; secondary outcomes included time to CT completion and emergency department (ED) length of stay.ResultsSeventeen studies involving 5033 patients met inclusion criteria. Non-contrast CT demonstrated sensitivity of 82.4-90.5% and specificity of 75-100%. Oral contrast-only protocols showed sensitivity of 73.5% and specificity of 80%. Combined oral + IV protocols achieved sensitivity of 89.4-100% and specificity of 54.5-98.5%. IV-only protocols provided sensitivity of 77.8-100% and specificity of 87-100%. Across studies, eliminating oral contrast reduced ED length of stay by 29-91 minutes without compromising diagnostic accuracy.ConclusionsIV-only or non-contrast CT protocols offer comparable diagnostic accuracy to oral contrast approaches while significantly improving workflow efficiency. Protocol selection should consider clinical setting and patient factors, reserving oral contrast for select groups such as oncology patients or those with prior abdominal surgery.