Triangular cord sign in detection of biliary atresia: is it a valuable sign?

Background: Early detection of biliary atresia (BA) has a vital role in prevention of liver cirrhosis in these patients. There are some evidences that triangular cord (TC) sign, i.e., triangular structure located cranial to the portal vein bifurcation on ultrasonographic examination, is suggestive of BA in suspected cases. The aim of this study is to evaluate and compare the sensitivity, specificity, and accuracy of TC sign with other methods of diagnosis such as hepatobiliary scan.

Methods: Fifty-eight infants referred to pediatric gastroenterology ward with diagnosis of infantile cholestasis from March 2004 to March 2008 were evaluated to find the cause of cholestasis. Diagnosis was made by means of history, clinical examination, hepatobiliary scan, and liver biopsy. Ultrasonographic examination was focused on presence of TC sign in patients. If the diagnosis was in favor of BA, patient was sent for direct cholangiography as a gold-standard test for confirmation of the diagnosis. The sensitivity, specificity, and accuracy of the tests were compared with golden standard.

Results: Among 58 infants with infantile cholestasis, BA was diagnosed and confirmed in 10 infants (17.2%). Hepatobiliary scintigraphy had 80% sensitivity, 72.9% specificity, and 74.1% accuracy. TC sign had 70% sensitivity, 95.8% specificity, and 91.3% accuracy.

Conclusion: TC sign is more accurate than hepatobiliary scan and has acceptable sensitivity and specificity for diagnosis of BA.