Normal ultrasonographic dimensions of the gallbladder and common bile duct in neonates

Background: Ultrasound (US) is the first choice of imaging in neonates presenting with persistent jaundice to exclude surgically correctable causes and differentiate obstructive from nonobstructive causes. Previous studies on normal dimensions of gallbladder (GB) and common bile duct (CBD) recruited adults and children spread across a wide age group. Aims: This study aimed to determine GB and CBD normal dimensions in a large homogeneous neonatal population as well as guide decision regarding pre-US fasting in neonates who require GB evaluation. Materials and Methods: Five hundred and twenty-eight healthy newborns were recruited between May 2009 and May 2011. The widest intraluminal anterior-posterior diameters of GB and CBD were measured. Neonatal age in days, sex, birth weight, weight and height, gestational age at delivery, and time interval since last feed recorded. Results: The mean age was 9.56 ± 7.66 days, and 50.6% were males. The mean CBD diameter was 1.16 ± 1.61 mm while the mean GB diameter was 4.42 ± 2.16 mm. GB and CBD were clearly seen and measurable in 297 (55.8%) neonates and 237 (44.38%) neonates, respectively. There was a significant correlation between CBD diameter and GB diameter (P = 0.04) but no correlation with any demographic parameter. GB visualization was not dependent on time interval from last feed. Conclusion: Mean neonatal values for CBD and GB were established, but neonates have a wider range of GB diameters compared with older children, so GB diameter may not be a reliable parameter for neonatal GB pathologies. GB visualization was not dependent on time interval from last feed; hence, a recent feed should not delay emergency scans, especially in ill neonates