Ultrasonography Versus MRI for Diagnosing Acute Appendicitis During Pregnancy

ABSTRACT

PURPOSE: The purpose of this study is to compare the sensitivity, specificity, positive predictive value, and negative predictive value of ultrasonography versus magnetic resonance imaging (MRI) in evaluation of pregnant patients with clinically suspicious acute appendicitis. METHODS: This study was a retrospective cohort study. A total of 60 pregnant patients who presented to the emergency department with suspected appendicitis and underwent ultrasonography or MRI were included. The official interpretation reports and pathologic reports were extracted and analyzed. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for ultrasonography and MRI for diagnosis of acute appendicitis. We also calculated and compared area under the curve (AUC) of both diagnostic tests with the receiver operating characteristic (ROC) curve analysis. RESULTS: Among 60 patients, 43 (71%) underwent ultrasonography, 37 (61%) underwent MRI, and 20 (33%) underwent both diagnostic tests. Twenty patients were confirmed as pathologically-proven acute appendicitis. The sensitivity, specificity, positive predictive value, and negative predictive value of ultrasonography for diagnosing acute appendicitis were 67%, 77%, 53%, and 86%, while those of MRI were 100% for all parameters. In ROC analysis, the AUC was 0.656, respectively, for ultrasonography, and 1.000 for MRI (p value<0.0001). CONCLUSION: This study suggests that MRI is more accurate than ultrasonography for the diagnosis of acute appendicitis in pregnant women, especially when the appendix is invisible with ultrasonography.