A Study on the Visibility and Radiological Characteristics of a Normal Appendix in Patients Undergoing Non-contrast Computed Tomography at Teaching Hospital Jaffna, Sri Lanka.

Background The appendix is a vermiform structure with a variable position, length, and thickness. Imaging plays a critical role in diagnosing an inflamed appendix, with non-contrast computed tomography (NCCT) being an effective modality when ultrasound is inconclusive. This study evaluates the visibility and anatomical characteristics of a normal appendix using NCCT. Methods This retrospective descriptive study was conducted in the Radiology Unit of Teaching Hospital Jaffna, in Jaffna, Sri Lanka, from September 2023 to February 2024, following approval from the Institutional Ethical Review Committee of the hospital. Two hundred individuals were evaluated (past appendectomy patients were excluded). IBM SPSS Statistics software, version 26 (IBM Corp., Armonk, NY, USA) was used, with significance assessed at P ≤ 0.05.  Results Males were 64.5%. The visibility rate was 89%. The most common positions were retrocecal (27.5%), retroileal (22%), and pelvic (21.5%). The mean length was 7.5 cm, with a base diameter of 6.6 mm, a mid-section of 6.2 mm, and a tip of 5.8 mm. Mean wall thickness was 2.6 mm, fecoliths were found in 15% of cases, and the mean distance of the base from McBurney's point was 3.32 cm. Conclusion NCCT can be used to assess the morphology, position, and presence of fecolith in equivocal cases of suspected appendicitis when ultrasound is inconclusive and contrast is contraindicated. The appendicular diameter and wall thickness can be used as evidence of inflammation. McBurney's point is a reliable anatomical guide during open appendicectomies. The presence of a fecalith itself is not a reliable indicator of appendicitis.