Gallbladder volume and contractility in term and preterm neonates: normal values and clinical applications in ultrasonography.

The aim of this study was to establish the normal values and evaluate associated factors of gallbladder volume and contractility in term and preterm neonates by using ultrasonography. Sonographic measurement of gallbladder volume was performed by using the ellipsoid method in 50 preterm and 46 term infants. We collected data soon after delivery and at 6-h fasting, and at 3-h and 6-h fasting following regular milk feeding. Serial postprandial changes of gallbladder volume and contractility were collected at 15-min intervals for one hour. Gallbladder contraction index (C.I.) was determined as percentage decrement of postprandial size from initial size. Fasting gallbladder volume was larger in term group (p < 0.05). Term neonates more readily showed significant contraction (C.I. > 50%; p < 0.05). In preterm infants significant contraction was clearly observed at postconceptional age > 31 weeks or body weight > 1300 g. The presence of hepatobiliary diseases might be detected by evaluating serial changes of gallbladder volume and contractility under ultrasonography in the neonatal stage.