Is "gallbladder length-to-width ratio" useful in diagnosing biliary atresia?

BACKGROUND: The accurate assessment of gallbladder shape and wall abnormalities by ultrasound (US) in diagnosing biliary atresia (BA) remains a subjective determination. The objective of this study was to examine the reliability of gallbladder length-to-width ratio (LTWR) by US measurement for diagnosis of BA.

METHODS: One hundred infants with conjugated hyperbilirubinemia and unknown cause of jaundice who underwent transabdominal US from February 2009 to February 2017 were enrolled. The gallbladder classification and other detailed US findings were reviewed.

RESULTS: There were statistical differences in gallbladder lumen, classification, length, width and LTWR of gallbladder (all P < 0.05) between BA and non-BA groups. The gallbladder LTWR with a cutoff at 4.1 had the highest sensitivity of 71.7%, while the fibrotic cord thickness had the highest specificity of 95.9%. The combination of portal vein (PV) diameter > 4.4 mm, hepatic artery (HA) diameter > 1.2 mm, and gallbladder LTWR >4.1, provided much higher specificity (98%), odds ratio (11), and positive likelihood ratio (LR+) (10.6).

CONCLUSION: The gallbladder LTWR by US could be a suggestive US parameter for BA screening. The triad of PV diameter, HA diameter, and gallbladder LTWR yielded the highest specificity, odds ratio, and LR+ for diagnosing BA.

LEVEL OF EVIDENCE: Level III study of diagnostic test.