Wall thickness and outer diameter of the normal appendix in adults using 64 slices multidetector CT

Abstract

Objective: Determine wall thickness and outer diameter of the normal appendix in adults using 64 slices multidetector CT Material and Method: A retrospective review of 538 patients (190 men, 348 women; mean age, 56.5 years + 15.2 SD) who were sent for abdomino-pelvic CT without clinical suspicion of acute appendicitis was conducted. Two radiologists blinded to the presented patient's history of appendectomy interpreted CT images regarding the visualization of the appendix, location, luminal contents and presence of appendicoliths. The maximum outer diameter and two walls thickness of the visualized appendices were measured. Results: The sensitivity, specificity, positive and negative predictive value, and accuracy for visualization of the appendix were 90.8%, 100%, 100%, 76.5% and 92.9% for reader 1 and 97.3%, 97.6%, 99.3%, 91.7% and 97.4% for reader 2. The mean maximum outer diameter of the appendix was 6.6 mm + 1.5 (range, 3.4-14.0 mm). The mean two walls thickness of the appendix was 4.4 mm + 1.0 (range, 1.6-8.0 mm). Conclusion: The normal appendix is frequently identified at 64 slices MDCT. Contrast to maximum outer diameter, normal two walls thickness of the appendix is infrequently exceeding the threshold of 6 mm.