- Diagnosis of the position of left liver bile duct stones: sensitivity: Se = 96.49%, specificity: Sp = 88.88%, accuracy: Acc = 94.04%, positive predictive value: PPV = 94.82%, negative predictive value: NPV = 92.30% - Diagnosis of the number of main bile duct stones: sensitivity: Se = 77.77%, specificity: Sp = 98.66%, accuracy: Acc = 96.42%, positive predictive value: PPV = 87.50%, negative predictive value: NPV = 97.36%.