Diagnostic performance of contrast-enhanced MR for acute appendicitis and alternative causes of abdominal pain in children

Abstract

Objective: Unenhanced MRI has emerged as a useful tool for diagnosing pediatric acute appendicitis. The use of contrast-enhanced MRI for diagnosing pediatric appendicitis has not been documented. The purpose of this study is to examine the diagnostic performance of contrast-enhanced MRI for acute appendicitis and alternative entities in the pediatric population presenting with acute abdominal pain.

Materials and methods: A retrospective review was conducted of 364 consecutive pediatric patients undergoing contrast-enhanced MRI for the evaluation of possible appendicitis at a single institution between November 2012 and September 2013.

Results: There were 132 cases of pathologically confirmed appendicitis out of 364 pediatric patients (36.3%) included in the study. Overall sensitivity and specificity were 96.2% (95% CI [91.4-98.4%]) and 95.7% (95% CI [92.3-97.6%]), respectively. Positive predictive value and negative predictive value were 92.7% (95% CI [86.6-96.3%]) and 97.8% (95% CI [94.7-99.1%]), respectively. The appendix was visualized in 243 cases (66.8%). Imaging confirmed alternative diagnoses in 75 patients, including most commonly colitis, enteritis or terminal ileitis (n = 25, 6.9%), adnexal cysts (n = 25, 6.9%) and mesenteric adenitis (n = 7, 1.9%).

Conclusion: Contrast-enhanced MRI is capable of accurately diagnosing acute appendicitis while detecting many alternative entities of abdominal pain, and it allows good visualization of the appendix. Further evaluation is needed to determine whether contrast-enhanced MRI provides an advantage over non-enhanced MRI for imaging evaluation of acute abdominal pain in the pediatric population.