Diagnostic Performance of Magnetic Resonance Imaging in the Detection of Appendicitis in Adults:

Rationale and Objectives

Perform a meta-analysis evaluating the diagnostic performance of magnetic resonance imaging (MRI) for the diagnosis of acute appendicitis.

Materials and Methods

MEDLINE and EMBASE were queried between January 1995 and December 2009. Prospective and retrospective studies were included if they: used MRI as a diagnostic test for appendicitis, used pathology or clinical follow-up as the reference standard, and reported absolute number of true-positive, true-negative, false-positive, and false-negative results, or stated sufficient data to derive these values. Summary sensitivity, summary specificity, positive and negative likelihood ratios (LR+) and (LR-), and diagnostic odds ratio were calculated. Heterogeneity of the results was assessed using Forest plots and the value of inconsistency index (I²).

Results

The inclusion criteria were fulfilled by eight articles with a total of 363 patients (mean age 26.9 ± 7.2 years; 86.2 % female). The appendix was not found in eight patients, with one article not reporting such data. The summary sensitivity was 97% (92%–99% at 95% confidence interval [CI]) and summary specificity was 95% (CI: 94%–99%), with a LR+ of 16.3 (CI: 9.1–29.1) and a LR- of 0.09 (CI: 0.04–0.197). Diagnostic odds ratio was 299.85 (CI: 97.5–921.61). No heterogeneity was found in the sensitivity (I² = 0.0, P = .4589). Minimal heterogeneity was found in the specificity (I² = 21.9%, P = .2553).

Conclusion

MRI appears promising in the evaluation of acute appendicitis, although larger future studies are warranted to confirm the results.

Key Words: Acute appendicitis, meta-analysis