Gallbladder ejection fraction declines with age in patients undergoing cholecystectomy for acalculous biliary symptoms but has low accuracy in the prediction of gallbladder pathology.

ABSTRACT

BACKGROUND/AIMS: Hepatobiliary Iminodiacetic Acid (HIDA) scan provides a technique to quantify gallbladder ejection fraction (EF) in patients suffering acalculous biliary colic (ACBC). We wished to evaluate the accuracy of EF in the prediction of gallbladder pathology in patients undergoing cholecystectomy. METHODS: Data were retrieved from a database of patients referred for HIDA scan for ACBC, including EF and the pathological outcome of those undergoing cholecystectomy, and compared to normal values obtained from a review of related studies. Significant associations were demonstrated by chi-square, Mann-Whitney test, and linear regression. The predictive accuracy of different cut-offs of EF was demonstrated by the ROC curve analysis. RESULTS: Of 83 patients referred for HIDA scan for ACBC, 41 underwent cholecystectomy. The median EF of this group (33%) was significantly lower than the composite normal median value from previous studies (56%). Thirty-two patients revealed evidence of gallbladder pathology. The EF declined with age (coefficient = -0.51, 95% CI = -0.99 to -0.33), but the median value did not differ between those with gallbladder pathology (34%) and those with normal gallbladders (29%). CONCLUSION/DISCUSSION: Although an EF cut-off of 35% had the greatest accuracy in the prediction of pathology of those tested (0.56), the poor negative predictive value (23.5%) was a major contributor to its low accuracy. Although patients with ACBC have reduced gallbladder EF compared to the normal population, its quantitative assessment is of limited value in the prediction of gallbladder pathology.