Comparison of Imaging Strategies with Conditional Contrast-enhanced CT and Unenhanced MR Imaging in Patients Suspected of Having Appendicitis: A Multicenter Diagnostic Performance Study

Purpose: To compare the diagnostic performance of imaging strategies with magnetic resonance (MR) imaging and computed tomographic (CT) imaging in adult patients suspected of having appendicitis. Materials and Methods: Institutional review board approval was obtained prior to study initiation, and patients gave written informed consent. In a multicenter diagnostic performance study, adults suspected of having appendicitis were prospectively identified in the emergency department. Consenting patients underwent ultrasonography (US) and subsequent contrast-enhanced CT if US imaging yielded negative or inconclusive results. Additionally, all patients underwent unenhanced MR imaging, with the Results: Between March and September 2010, 229 US, 115 CT, and 223 MR examinations were performed in 230 patients (median age, 35 years; 40% men). Appendicitis was the final diagnosis in 118 cases. Conditional and immediate MR imaging had sensitivity and specificity comparable to that of conditional CT, which resulted in 3% (three of 118; 95% confidence interval [CI]: 1%, 7%) missed appendicitis, and 8% (10 of 125; 95% CI: 4%, 14%) false-positives. Conditional MR missed appendicitis in 2% (two o Conclusion: The accuracy of conditional or immediate MR imaging was similar to that of conditional CT in patients suspected of having appendicitis, which implied that strategies with MR imaging may replace conditional CT for appendicitis detection. (C) RSNA, 201