Visualization of the normal appendix with MR enterography in children.

Background: Magnetic resonance (MR) imaging may provide a radiation-sparing alternative to CT in diagnosing appendicitis in children in whom US is equivocal. However, comparability with CT in the detection of the appendix remains to be established.

Objective: To determine the detection rate of the normal appendix in children on oral and IV contrast-enhanced MRI.

Methods: MR imaging of 58 patients who had previously undergone MR enterography was retrospectively reviewed. Detection rate, body mass index, age and gender were recorded.

Results: The normal appendix was detected in 28 cases (48%), with greatest detection rate on the axial fast imaging employing steady-state acquisition (FIESTA) sequence. Children in whom the appendix was detected had significantly higher BMI compared to children in whom the appendix was not seen. Neither age nor gender demonstrated a significant association with detection rate.

Conclusion: The detection rate of the normal appendix in children on oral and IV contrast-enhanced MRI was 48%, which is comparable to detection rates on CT, as well as to previously reported detection rates on MR imaging with neither oral nor IV contrast agents. These findings may serve to guide the development of MRI protocols for pediatric appendicitis.