Purpose: To develop objective criteria for the ultrasonographic (US) appearance of the triangular cord (TC) sign for the diagnosis of biliary atresia.
Materials and methods: US was performed in 86 infants with jaundice. Biliary atresia (n = 20) was confirmed with hepatoportoenterostomy. Neonatal hepatitis (n = 66) was diagnosed with needle biopsy (n = 5), cholescintigraphy (n = 19), or clinical findings (n = 42). Thickness of the echogenic anterior wall of the right portal vein (EARPV) was measured. The TC sign was defined as thickness of the EARPV of more than 4 mm on a longitudinal scan. Biliary atresia was diagnosed when the TC sign was present. Statistical analyses were performed to compare the thickness of the EARPV between patients with biliary atresia and those with neonatal hepatitis and to test the significance of a 4-mm thickness as the criterion for the TC sign in the differentiation of biliary atresia from neonatal hepatitis (P <.05).
Results: The TC sign was present in 16 (80%) of 20 patients with biliary atresia and in one of 66 patients with neonatal hepatitis. Mean thickness of the EARPV was significantly greater in patients with biliary atresia (5.39 mm) than in patients with neonatal hepatitis (2.17 mm) (P <.05). Use of 4-mm thickness as the criterion for TC sign was statistically significant (P <.05), resulting in a sensitivity of 80%, specificity of 98%, and positive and negative predictive values of 94% for the diagnosis of biliary atresia.
Conclusion: An objective criterion of the TC sign is an EARPV thicker than 4 mm on a longitudinal scan.
Copyright RSNA, 2003