Ultrasonographic Measurement of the Diameter of a Normal Bile Duct, Hepatic Artery and Portal Vein in Infants Younger Than 3 Months

Kim, Sang Yoon; Lee, Young Seok

Abstract

PURPOSE
This study focused on measuring the diameter of the normal bile duct,hepatic artery and portal vein with high resolution US in infants younger than 3 months, and we wanted to determine the relative ratio of these diameters.
MATERIALS AND METHODS
Fifty US examinations were performed on infants younger than 3 months and who did not have any clinical or laboratory abnormality associated with the hepatobiliary system. We measured the diameter of the bile duct, hepatic artery and portal vein at the level of the portal vein bifurcation with using 17-5 MHz US and we determined the relative ratios of these diameters. To evaluate the statistical difference in the diameter of the bile duct, hepatic artery and portal vein, we performed one-way ANOVA and Scheffe's multiple comparison test. To determine the relative ratio of these diameters, the ratio of the bile duct to the hepatic artery was defined as the hepatic artery/bile duct, the ratio of the hepatic artery to the portal vein was defined as the portal vein/hepatic artery and the ratio of the bile duct to the portal vein was defined as the portal vein/bile duct. We calculated the averages +/- standard deviations of this data (minimum ~ maximum).
RESULTS
In all fifty infants, the bile duct, hepatic artery and portal vein were detectable and measurable. The average diameter of a bile duct was 0.85 +/- 0.19 mm (0.56 ~ 1.47 mm), it was 1.33 +/- 0.31 mm (0.90 ~ 2.37 mm) for the hepatic artery and 3.32 +/- 0.68 mm (2.06 ~ 5.08 mm) for the portal vein. The diameter of these structures was significantly different from each other according to one-way ANOVA (p < 0.001). The average diameter of the hepatic artery was significantly larger than that of the bile duct and the average diameter of the portal vein was significantly larger than that of bile duct and hepatic artery on Scheffe's multiple comparison test. The relative ratio of the bile duct to the patic artery was 1.60 +/- 0.41 (0.77 ~ 2.66), that of the hepatic artery to the portal vein was 2.53 +/- 0.69 (1.16 ~ 4.30) and that of the bile duct to the portal vein was 3.93 +/- 1.04 (2.08 ~ 6.60).
CONCLUSIONS
The diameter of the normal bile duct, hepatic artery and portal vein measured in this study and the relative ratios of these structures could be a useful reference for the US evaluation of infants who are suspected of having hepatobiliary disease. Key words : Infant