The equivocal appendix at CT: prevalence in a control population.

Area of Science:

• Radiology
• Medical Imaging
• Gastrointestinal Imaging

Background:

• Appendicitis diagnosis relies on imaging, but normal appendix variations can mimic pathology.
• Computed tomography (CT) is a key tool for evaluating abdominal pain and potential appendicitis.

Purpose of the Study:

• To determine the prevalence of equivocal appendix appearances on CT in a control population.
• To establish baseline CT findings for normal appendices to aid in differentiating from appendicitis.

Main Methods:

• Retrospective review of 150 patients undergoing abdominal/pelvic CT for hematuria without acute symptoms.
• Measurement of appendiceal diameter and assessment for isodense appearance or airless/fluid-filled lumen by a single reader.

Main Results:

• 44.6% of normal appendices had a diameter > 6 mm.
• 22.7% of normal appendices were collapsed or isodense.
• 6.6% of normal appendices were isodense with diameter > 6 mm (none > 10 mm).
• 0.67% of normal appendices showed airless fluid in the lumen (diameter < 6 mm).

Conclusions:

• A normal appendix can frequently exceed 6 mm in diameter.
• Isodense appearance with diameter between 6-10 mm occurs in 6.6% of normal individuals.
• Airless fluid in the normal appendix lumen is a rare finding (<1%).