Age-Related Variations in Common Bile Duct Diameter: Implications for Diagnostic Accuracy

Background: Dilation of the common bile duct (CBD) is a frequently observed phenomenon, particularly in the aging population. Several clinical conditions, including choledocholithiasis, strictures, tumors, previous surgeries, and periampullary diverticula, may contribute to CBD enlargement. However, age-related physiological changes may also cause gradual dilation, potentially confounding diagnostic interpretations. Objective: This study aims to assess the variation in CBD diameter among different age groups, in order to establish age-specific reference values and avoid misdiagnosis. Methodology: A descriptive cross-sectional study was conducted at the Department of Diagnostic Radiology, Saidu Group of Teaching Hospital, Swat. Data collection spanned from March 22, 2022, to June 30, 2022. All patients undergoing ultrasonography who met the inclusion criteria were enrolled. Written informed consent was obtained from each participant. CBD diameter was measured using high-resolution ultrasonography. Results: The mean CBD diameter across all patients was 5.3 ± 1.4 mm. Age-stratified analysis revealed progressive enlargement with age: 4.5 mm in patients <30 years, 4.8 mm in those aged 31–40 years, 5.2 mm in the 41–50 years group, 5.4 mm in the 51–60 years group, and 6.6 mm in patients aged ≥61 years. The differences in mean CBD diameter across age groups were statistically significant (p-value = 0.001). Conclusion: The study found a significant age-related increase in CBD diameter. Recognizing this physiological expansion is essential to avoid over-diagnosis of pathological conditions. Age-specific normal ranges for CBD diameter should be considered in clinical practice to improve diagnostic accuracy, especially in elderly patients.