MRI of the normal appendix in children: data toward a new reference standard

Area of Science:

• Pediatric Radiology
• Diagnostic Imaging
• Gastrointestinal Imaging

Background:

• Limited literature exists on normal pediatric appendix appearance on MRI.
• MRI offers a radiation-free alternative to CT for diagnosing pediatric appendicitis.

Purpose of the Study:

• To define the MRI characteristics of the normal pediatric appendix.
• Establish a reference standard for pediatric appendix imaging via MRI.

Main Methods:

• Retrospective review of pediatric lumbar spine/pelvis MRI scans (2013).
• Exclusion of scans for appendicitis-related indications.
• Independent radiologist assessment of appendix visualization, diameter, intraluminal content, and surrounding inflammation/fluid.

Main Results:

• Appendix visualized in 55.5% of 346 pediatric patients.
• Median appendix diameter: 5-6 mm (range 2-11 mm).
• Variable intraluminal signals; no inflammation; 3.1% had free fluid.

Conclusions:

• The normal pediatric appendix is visualized on MRI in about half of cases.
• Typical MRI findings include a 5-6 mm diameter, variable intraluminal signals, and absence of inflammation.
• MRI can characterize the normal appendix, aiding in the diagnosis of appendicitis in children.