Sonographic diagnosis of biliary atresia in pediatric patients using the "triangular cord" sign versus gallbladder length and contraction

OBJECTIVE: A retrospective review was performed to evaluate the importance of the "triangular cord" sign in comparison with gallbladder length and contraction for the diagnosis of biliary atresia in pediatric patients. MATERIALS AND METHODS: Fifty-five fasting infants with cholestatic jaundice were examined on sonography. The examinations focused on the visualization of the triangular cord sign and assessment of gallbladder length and contraction. The diagnosis of neonatal hepatitis or of other causes of infantile cholestasis was made if symptom resolution occurred during follow-up. RESULTS: A triangular cord sign was found in 27 of 29 infants with biliary atresia and in one of 26 infants with neonatal hepatitis or other causes of infantile cholestasis. The diagnostic accuracy was 95%, sensitivity was 93%, and specificity was 96%. The gallbladder was thought to be abnormal if it was less than 1.5 cm long, was not detectable, or was detectable but had no lumen. The gallbladder was abnormal in 21 of 29 infants with biliary atresia, whereas it was abnormal in eight of 26 infants with neonatal hepatitis or other causes of infantile cholestasis. The diagnostic accuracy was 71%, sensitivity was 72%, and specificity was 69%. The gallbladder was detectable on sonography in 13 infants with biliary atresia and 26 infants with neonatal hepatitis or other causes of infantile cholestasis. Gallbladder contraction was not confirmed in 11 of 13 infants with biliary atresia and seven of 26 infants with neonatal hepatitis or other causes of infantile cholestasis. The diagnostic accuracy was 77%, sensitivity was 85%, and specificity was 73%. CONCLUSION: The triangular cord sign was a more useful sonographic finding for diagnosing biliary atresia than gallbladder length and contraction.