Development and external validation of a dual-energy CT-biochemical score for the detection of radiolucent common bile duct stones

PURPOSE: ) mapping for detecting radiolucent common bile duct (CBD) stones and to develop and externally validate a simple, combined imaging-biochemical score. MATERIALS AND METHODS: map positivity, conjugated bilirubin or gamma-glutamyl transferase serum levels, which was then validated in an external validation cohort. RESULTS: map positivity (odds ratio [OR], 18.69; 95% CI: 4.22-82.68; P < 0.001) and conjugated bilirubin ≥ 50 µmol/L and/or γ-glutamyl transferase > 500 IU/L (OR, 20.67; 95% CI: 3.39-126.09; P = 0.001) were two variables that were independently associated with CBD stones. These two variables were combined into the ZBG score, with 1 point assigned to each item. The resulting ZBG score (range: 0-2) showed an area under the curve of 0.870 (95% CI: 0.801-0.939) in the derivation cohort and 0.877 (95% CI: 0.791-0.963) in the validation cohort for the diagnosis of radiolucent CBD stones. CONCLUSION: mapping and routine cholestatic biomarkers provides accurate risk stratification for radiolucent CBD stones.