OBJECTIVE. Acute appendicitis is the most common indication for emerge
ncy abdominal surgery. To our knowledge, MR imaging has not been compa
red with sonography for revealing acute appendicitis. Our aim was to a
ssess and compare the accuracy, advantages, and limitations of MR imag
ing and sonography in revealing appendicitis. SUBJECTS AND METHODS. Th
e study included 60 consecutive patients suspected of having appendici
tis who underwent abdominal sonography and MR imaging. Fat-suppressed
T2-weighted fast spin-echo and gadolinium-enhanced fat-suppressed T1-w
eighted spin-echo axial and coronal images were obtained. The initial
MR imaging and sonographic studies were later correlated with the surg
ical-pathologic findings, follow-up evaluations, and diagnosis at the
time of discharge. RESULTS. Surgical, histopathologic, and follow-up r
esults revealed that 34 patients had appendicitis. Of the 26 patients
without appendicitis, 15 with symptoms of acute appendicitis had no pa
thologic diagnoses and the remaining 11 had another diagnosis. Compari
son of the sensitivity, accuracy, and negative predictive values for M
R imaging and sonography was found to be statistically significant (p
<.05, chi-square test), indicating that MR imaging was superior to son
ography in revealing appendicitis. We found no statistical difference
in specificity and positive predictive value for MR imaging and sonogr
aphy. CONCLUSION. Despite some disadvantages, we found MR imaging to b
e superior to sonography in revealing suspected acute appendicitis. MR
imaging can be used after suboptimal or nondiagnostic sonography in c
ases of suspected acute appendicitis.