Acute appendicitis: MR imaging and sonographic correlation.

OBJECTIVE: Acute appendicitis is the most common indication for emergency abdominal surgery. To our knowledge, MR imaging has not been compared with sonography for revealing acute appendicitis. Our aim was to assess and compare the accuracy, advantages, and limitations of MR imaging and sonography in revealing appendicitis.

SUBJECTS AND METHODS: The study included 60 consecutive patients suspected of having appendicitis who underwent abdominal sonography and MR imaging. Fat-suppressed T2-weighted fast spin-echo and gadolinium-enhanced fat-suppressed T1-weighted spin-echo axial and coronal images were obtained. The initial MR imaging and sonographic studies were later correlated with the surgical-pathologic findings, follow-up evaluations, and diagnosis at the time of discharge.

RESULTS: Surgical, histopathologic, and follow-up results revealed that 34 patients had appendicitis. Of the 26 patients without appendicitis, 15 with symptoms of acute appendicitis had no pathologic diagnoses and the remaining 11 had another diagnosis. Comparison of the sensitivity, accuracy, and negative predictive values for MR imaging and sonography was found to be statistically significant (p < .05, chi-square test), indicating that MR imaging was superior to sonography in revealing appendicitis. We found no statistical difference in specificity and positive predictive value for MR imaging and sonography.

CONCLUSION: Despite some disadvantages, we found MR imaging to be superior to sonography in revealing suspected acute appendicitis. MR imaging can be used after suboptimal or nondiagnostic sonography in cases of suspected acute appendicitis.