Computed tomography evaluation of variations in positions and measurements of appendix in patients with non-appendicular symptoms: time to revise the diagnostic criteria for appendicitis.

Abstract

To estimate the frequency distribution of different anatomical positions, and to measure the diameter, wall thickness, and length of appendix in patients with non-appendicular symptoms. This retrospective observational study was conducted among 1,575 patients, who had undergone computed tomography (CT) scan of abdomen for various non-appendicular signs and symptoms. Frequency of distribution of different anatomic locations and measurements of various morphologic parameters were recorded. The most common location of appendix was retrocecal, followed by sub-cecal, post-ileal, and pelvic locations. The mean length of appendix was 66.7 mm (range, 6.3-123 mm), and the diameter was 6.3 mm (range, 2.8-11.3 mm). Diameter of > 6 mm was noted in 48.12% patients. The mean wall thickness was 2.37 mm, ranging 1.2-4.2 mm. The most common intra-luminal content was air-mixed with hypodense or hyperdense material observed in 70.5% of cases. Although an appendix with diameter less than 6 mm may be considered normal, a diameter above 6 mm has an overlap between a normal and inflamed appendix. Therefore, it should be considered in association with clinical and secondary findings to avoid overdiagnosis and unnecessary appendicectomies. We strongly recommend that diameter-based CT criteria to diagnose appendicitis should be revised and standardized.